Polycrystalline diamond with surface depleted of catalyzing material

Polycrystalline diamond with catalytic material to reduce the surface

Technical field

The invention relates to a superhard polycrystalline material element that can be used for wear resistance, cutting, wire drawing, and other applications that require engineering superhard surfaces. The present invention particularly relates to polycrystalline diamond and polycrystalline diamond-like diamond (collectively referred to as PCD) elements with greatly improved wear resistance and their preparation methods.

Background technique

For ease of description, it is known that polycrystalline diamond and polycrystalline diamond-like elements are referred to as PCD elements. The PCD element is made of a carbon matrix material with a particularly short interatomic distance between adjacent atoms. A polycrystalline diamond-like material, called carbon nitride (CN), is disclosed in US5776615. Another more common form of PCD will be described in more detail below. Generally, PCD components are made of a mixed material, processed under high temperature and high pressure into a polycrystalline matrix of internally bonded superhard carbon-based crystals. A common feature of PCD elements is the use of catalytic materials during their formation. When in use, their residues often have a certain restrictive effect on the maximum usable operating temperature of the elements.

A well-known man-made PCD element is a two-layer or multi-layer PCD element in which a facing table of polycrystalline diamond is integrally bonded to a matrix of a low-hardness material such as tungsten carbide of. The PCD element can be a circular or semicircular sheet, or can be made into other shapes suitable for applications, such as hollow molds, heat sinks, friction bearings, valve surfaces, pressure cones, machine tool spindles, and the like. This type of PCD components can be used in almost all applications that require hard wear and corrosion resistance. The substrate of the PCD element can be brazed to a support, which is often composed of bonded tungsten carbide. For PCD's used as cutting elements, this is a commonly used structure, for example, a fixed cutting edge or cone that is housed in the drill socket or fixed to a column of a machine tool used for machining. Drill bit. These PCD components are often referred to as PDC's.

Another form of PCD element is a single PCD element without an integral matrix, in which a polycrystalline diamond plane is fixed to a tool or a wear-resistant surface by a mechanical method or a bonding method. These PCD elements are different from the above-mentioned elements because diamond particles are present in the entire element. These PCD elements can be mechanically fixed in place, they can be embedded in a larger PCD element with a matrix, or, as an alternative, they can be made of a metal layer, and they can be made of a metal layer. Soldering or welding together. A large number of these PCD elements can be made from a single PCD, for example, as shown in US4481016 and US4525179, all of their published contents can be incorporated herein by reference.

PCD elements are often made by sintering diamond powder with a suitable binder-catalytic material in a high-pressure, high-temperature press forging machine. A specific method for forming this kind of polycrystalline diamond is disclosed in US3141746, and the entire disclosure of it can be incorporated herein by reference. In a common method of preparing PCD components, diamond powder is coated on the surface of a prefabricated cobalt-bonded tungsten carbide substrate. This part is then subjected to a very high temperature and pressure treatment in a press forging machine. In this process, cobalt migrates from the matrix into the diamond layer and acts as a binder-catalytic material, so that the diamond particles are bonded to each other through the diamond-diamond bond, thereby also making the diamond layer adhere to each other. Knot onto the substrate.

A complete PCD element has at least one matrix of diamond crystals bonded to each other, which has many gaps containing the above-mentioned binder-catalytic material. The diamond crystal contains a first continuous diamond matrix, and the gap forms a second continuous gap matrix containing the binder-catalytic material. Moreover, there must be a relatively small amount of areas where the diamond-diamond growth has already encapsulated part of the binder-catalytic material.

In a common form, the diamond element accounts for 85%-95% of the volume, and the binder-catalytic material accounts for another 5-15%. This type of element is prone to thermal degradation, because the gap between the cobalt binder-catalytic material and the diamond matrix begins to have different thermal expansions at a temperature of about 400°C. When sufficient expansion is achieved, the diamond-diamond bond may break, causing cracks and fragments.

In polycrystalline diamond, the presence of the binder-catalytic material in the interstitial areas of the diamond crystals bonded to the diamond matrix can cause another form of thermal degradation. Due to the presence of the binder-catalytic material, the diamond will begin to graphitize when the temperature rises, and the operating temperature is typically limited to about 750°C.

Although cobalt is the most commonly used binder-catalytic material, any group VIII element including cobalt, nickel, iron, and their alloys can be used.

In order to reduce thermal degradation, polycrystalline diamond elements called "thermally stable" have been produced as prefabricated PCD elements for cutting and/or wear-resistant elements. As described in US4224380, all the contents disclosed can be combined Enter this article. In a thermally stable PCD element, the cobalt or other binder-catalytic material in conventional polycrystalline diamond is leached from the continuous interstitial matrix after formation. Although this can increase the high temperature resistance of the diamond to about 1200°C, this leaching method also removes the bonded carbide matrix. Moreover, because there is no integral substrate or other bondable surface, it becomes very difficult to install such materials during operation and use.

The methods used to produce such "thermally stable" PCD components usually produce relatively low diamond densities, with levels of about 80% or less. This low diamond density can ensure a thorough leaching process, but the final finished part is usually relatively weak in terms of impact strength.

In an alternative form of thermally stable polycrystalline diamond, silicon is used as the catalytic material. The method of using a silicon catalytic material to make polycrystalline diamond is very similar to the above method. The difference is that the synthesis temperature and pressure are different. Most of the silicon reacts to form silicon carbide, and it is not an effective Catalytic material. Its heat resistance has been improved to a certain extent, but thermal degradation will still occur. This is because there are still some residual silicon, which is usually evenly distributed in the gaps of the gap matrix. Moreover, for such PCD components, there is also a problem of difficulty in installation, because there is no surface that can be bonded.

Recently, another type of PCD can be used, in which, when sintering the diamond powder, carbonate powders such as Mg, Ca, Sr and Ba are used as the binder-catalytic material. This type of PCD usually has higher wear resistance and hardness than previous types of PCD components. However, the material is difficult to produce on an industrial scale because it requires very high pressure for sintering compared to the case of conventional and thermally stable polycrystalline diamond. As a result, the polycrystalline diamond body prepared by this method is smaller than the conventional polycrystalline diamond element. Moreover, thermal degradation may still occur due to residual binder-catalytic material remaining in the gap. Moreover, because there is no integral substrate or other bondable surface, it is difficult to install this material on the work surface.

Efforts to combine thermally stable PCD's with mounting systems to apply their improved temperature stability have not achieved the expected success due to their low impact strength. For example, US4726718, US5199832, US5025684, US5238074, and US5009963 disclose a variety of methods for installing multilayer PCD components, and all of their disclosures can be incorporated herein. Although most of these designs have achieved commercial success, the designs are not particularly effective in combining high wear and/or abrasion resistance while maintaining the level of toughness obtainable in non-thermally stable PCD.

Other types of diamond or diamond-like coatings for surfaces are disclosed in US4976324, US5213248, US5337844, US5379853, US5496638, US5523121, US5624068, and all of their disclosures can be incorporated herein. Similar coatings are also disclosed in GB2268768, PCT96/34131, and EPC500253, 787820, and 860515 for high-load tool surfaces. In these publications, diamond and/or diamond-like carbon coatings are applied to surfaces for wear and/or corrosion resistance.

In most of the above applications, physical vapor deposition (PVD) and/or chemical vapor deposition (CVD) methods are used to coat the diamond or diamond-like coating. PVD and CVD diamond coating methods are well known. For example, they are disclosed in US5439492, US4707384, US4645977, US4504519, and US4486286, and they can be incorporated herein.

The PVD and/or CVD method using diamond or diamond-like coating to coat the surface, for example, can also be used to provide a set of tightly compacted epitaxially oriented diamond crystals or other superhard crystals on a surface. Although these materials have a very high diamond density, because they are tightly compacted, there is no large number of diamond-diamond bonds between adjacent crystals, making them very fragile as a whole. When high shear is applied When the load is shedding, they are easily broken. As a result, although these coatings have a very high diamond density, they tend to have poor mechanical properties, making them very poor when used in high-load applications such as cutting elements, bearing devices, wear-resistant components, and molds. The impact strength and wear resistance.

People have also tried to improve the toughness and wear resistance of these diamond or diamond-like coatings by coating them on a tungsten carbide substrate and then processing them in a high-pressure and high-temperature environment, as described in US5264283, US5496638, and US5624068. All their disclosures are incorporated into this article. Although this type of processing can improve the wear resistance of the diamond layer, the abrupt change between the high-density diamond layer and the matrix makes the diamond layer difficult to Large-scale fractures easily occur at the interface. This will translate into very poor toughness and impact properties when in use.

When PCD elements made of cobalt or other Group VIII metal binder-catalytic materials are placed close to each other as the bearing material, it has been found that the coefficient of friction tends to increase during use. As described in EP617207, it has been found that removing the cobalt-rich friction film (which is easy to form during use) from the surface of the PCD bearing element will temporarily alleviate this problem. Obviously, when two PCD elements lie against each other as a bearing, part of the cobalt migrates from the PCD surface to the load area of the bearing during operation, causing increased friction. It is currently believed that the source of this cobalt may be a residual by-product of the processing of the bearing element, because acid wipe repair cannot effectively remove the cobalt to any significant depth below the surface.

Because the cobalt is only removed from the surface of the PCD, there is no effective change in the temperature when thermal degradation occurs in these bearing elements. Therefore, the harmful effect of the binder-catalytic material is still maintained, and the thermal degradation of the diamond layer due to the presence of the catalytic material still occurs.

Brief description of the invention The present invention provides a hyperpolycrystalline diamond or diamond-like carbon element, which has greatly improved heat-resistant degradation performance without loss of impact strength. For ease of description, they are collectively referred to as PCD elements. These elements are made of a binder-catalytic material in high temperature and high pressure processing. The PCD element has a large number of partially bonded diamond or diamond-like crystals, which form at least one continuous diamond matrix, and the gaps between the diamond crystals, which form at least one continuous containing a catalytic material Interstitial matrix. The element has a working surface and a main body, wherein the part of the interstitial matrix in the main body adjacent to the working surface is substantially free of the catalytic material, and the remaining interstitial matrix contains the catalytic material .

The part of the working surface on the main body of the PCD element may be post-processed so that the gaps in the superhard crystals are substantially free of catalytic materials. The working surface substantially free of the catalytic material will not be affected by thermal degradation encountered in other areas of the working surface, so that the performance of resistance to thermal degradation can be improved. In the cutting element, the treated working surface may be a part of the facing surface of the main body, a part of the peripheral surface of the main body, or a part of all these surfaces.

In another embodiment, the catalytic material is cobalt or other iron group metals, and the method of reducing the catalytic material is to remove from the gap near the surface of a PCD element in an acid etching process. It leaches. It is expected that the method of removing the catalytic material from the surface can also be carried out by electric discharge, or other electronic or electroplating methods, or by evaporation.

In another embodiment, the catalytic material is then removed from the working surface of a PCD element by chemically bonding it with other materials, so that it no longer acts as a catalytic material. In this method, a material may be left in the gaps among the diamond crystals, but the material no longer acts as a catalytic material-effectively removing or reducing the catalytic material.

In yet another embodiment, the catalyst material can be removed by converting it into a substance that no longer acts as a catalyst material. This can be achieved through a crystal structure change, chemical "processing", heat treatment, or other treatment methods. This method can be applied to non-metallic or non-reactive catalytic materials. Moreover, a material may remain in the gaps among the superhard material crystals, but the material no longer acts as a catalytic material-effectively removing or reducing the catalytic material.

An element is disclosed that contains a large number of partially bonded diamond crystals, a catalytic material, an interstitial matrix, and a main body with a working surface. The interstitial matrix in the main body adjacent to the working surface is substantially free of the catalytic material, while the remaining interstitial matrix contains the catalytic material.

Similarly, a PCD element is disclosed, which has a catalytic material, an interstitial matrix, and a main body with a working surface. The interstitial matrix in the main body adjacent to the working surface is substantially free of the catalytic material, while the remaining interstitial matrix contains the catalytic material.

Also, a PCD element is disclosed, which has a large number of superhard crystals, a catalytic material, and a main body with a working surface. In this element, most of the crystals in the main body with a depth of at least 0.1 mm from the working surface have a surface that is substantially free of the catalytic material, and the remaining crystals are related to the catalytic material. The material is in contact.

Moreover, a PCD element is disclosed, which has a main body with a working surface. A catalytic material is contained in the first volume of the main body far from the working surface, and the catalytic material is contained in the second volume of the main body adjacent to the working surface.

Also, an element is disclosed that has a large number of partially bonded diamond crystals, a catalytic material, and a body with a working surface. The volume of the body adjacent to the working surface has a diamond density significantly higher than other places in the body, and the volume is substantially free of the catalytic material.

Also, a PCD element is disclosed, which has a main body with a working surface. The volume of the body adjacent to the working surface has a diamond density significantly higher than other places in the body, and the volume is substantially free of a catalytic material.

In addition, a prefabricated cutting element is disclosed. The element has a veneer surface of a superhard polycrystalline material with a large number of partially bonded superhard crystals, a large number of gap regions existing between the superhard crystals, and a catalytic material. The facing surface has a cut surface and a main body. The gap area in at least a part of the cut surface is substantially free of the catalytic material, while the remaining gap area contains the catalytic material.

The PCD of the present invention can be used for wear resistance, cutting, wire drawing, and other superhard polycrystalline material components that require engineering superhard surface applications. The specific application is to be used as a cutting element in a rotary drill bit of a fixed cutting edge type or a cone type, as a hollow mold, a heat sink, a friction bearing, a valve surface, a pressure cone, a machine tool spindle, etc. The PCD element of the present invention can be used to process worn wood products, ferrous and non-ferrous materials, and very hard or corrosive engineering materials such as stone and asphalt.

Brief Description of the Drawings Fig. 1A is a typical PCD element of the present invention.

Figure 1B is a typical PCD of the present invention used as a cutting element.

Fig. 2 is a side view of a fixed cutting edge rotary drill using a PCD element according to the present invention.

Figure 3 is a perspective view of a roller cone rotary drill bit using a PCD element according to the present invention.

Fig. 4 is a perspective view of an insert used in a machine tool using the PCD element of the present invention.

Figure 5 is a perspective view of a dome-shaped PCD element used in a roller cone bit and a fixed cutting edge bit.

Fig. 6 is a photomicrograph of the surface of a PCD element in the prior art to illustrate the binder-catalytic material in the gap region.

FIG. 7 is a photomicrograph of the PCD element of the present invention to illustrate the first part with a catalytic material in the gap area and the second part without the catalytic material in the gap area.

FIG. 8 is a schematic diagram of a microstructure of a PCD element in the prior art, which is used to illustrate the crystal orientation of bonded diamond crystals and individual crystals with gap regions.

FIG. 9 is a schematic diagram of the microstructure of the PCD element of the present invention as shown in FIG. 7, which is used to indicate the depth of the area without catalytic material relative to the surface of the PCD element.

Fig. 10 is a curve of relative wear index of various embodiments of the PCD element of the present invention.

FIG. 11A is a front view of a packaged PCD embodiment of the PCD component of the present invention.

11B is a cross-sectional view of another packaged PCD embodiment of the PCD element of the present invention.

11C is a cross-sectional view of another packaged PCD embodiment of the PCD element of the present invention.

Fig. 12A is a perspective view of the CVD/PVD coated surface of another embodiment of the PCD element of the present invention.

Fig. 12B is an enlarged perspective view of the crystal structure of the embodiment of the PCD element of the present invention shown in Fig. 12A.

Fig. 13 is a cross-sectional view of a drawing die with the PCD element of the present invention.

Fig. 14 is a perspective view of a heat sink with the PCD element of the present invention.

Figure 15 is a perspective view of a bearing with the PCD element of the present invention.

16A and 16B are front views of a fitting part of a valve with a PCD element according to the present invention.

Figure 17A is a side view of a pressure cone with the PCD element of the present invention.

Fig. 17B is a partial cross-sectional view of a punch having the PCD element of the present invention.

Figure 18 is a perspective view of a measuring device with the PCD element of the present invention.

Detailed description and preferred embodiments of the invention The polycrystalline diamond or diamond-like carbon material (PCD) element 2 of the present invention is shown in FIG. 1A. The PCD element 2 has a large number of partially bonded superhard diamond or diamond-like crystals 60, (as shown in FIGS. 7 and 9) a catalytic material 64, and a kind of gap 62 formed in the crystal 60 The interstitial matrix 68. The element 2 also has one or more working surfaces 4, and the diamond crystal 60 and the gap 62 form the volume of the main body 8 of the PCD element 2.

The working surface 4 is any part of the PCD main body 8, which can be in contact with the object to be processed during operation. In this specification, when discussing the working surface 4, it should be understood that it is applicable to any part of the main body 8, which may be exposed and/or used as a working surface. Moreover, any part of all working surfaces 4, within and itself, is a working surface.

In the manufacturing process, under the conditions of high temperature and high pressure, the gap 62 in the crystal 60 is filled with the catalytic material 64 to form a bond in the crystal 60. In the next step of the manufacturing process, part of the catalytic material 64 is selectively reduced from part of the gap 62. As a result, the first volume of the main body 8 of the PCD element 2 far from the working surface 4 contains the catalytic material 64, and the second volume of the main body 8 adjacent to the working surface 4 is substantially free of The catalytic material 64. The gap 62 substantially free of the catalytic material 64 is indicated by the mark 66.

Therefore, the interstitial matrix 68 adjacent to at least a part of the main body 8 of the working surface 4 is substantially free of the catalytic material 64, while the remaining interstitial matrix 68 contains the catalytic material 64. The PCD element 2 can be bonded to a base 6 of a low-hardness material, usually bonded tungsten carbide, but the use of the base 6 is not necessary.

Since the main body adjacent to the working surface 4 is substantially free of the catalytic material 64, the harmful effects of the binder-catalytic material 64 are basically reduced, so the presence of the catalytic material 64 causes The thermal degradation of the working surface 4 can be effectively eliminated. As a result, a new type of PCD element 2 is obtained, which has enhanced thermal performance similar to the so-called thermally stable PCD element, while maintaining the toughness, manufacturing convenience, and bonding ability of the conventional PDC element. This can be translated into higher wear resistance in cutting applications, higher heat transfer capacity in heat sink applications, higher load capacity in bearing applications, lower surface deformation performance in valve applications, and advantageous It is used in a large number of other applications including hollow molds, pressure cones, machine tool spindles and wear components. The specific application details of the new PCD element 2 will be discussed in more detail later in this specification.

Referring now to the photomicrograph of the prior art PCD element in FIG. 6 and the schematic diagram of the microstructure of the prior art PCD element in FIG. 8, it is well known that the diamond or diamond-like crystal 60 has a disordered crystal phase orientation, such as The parallel lines of the cleavage plane of each crystal 60 are shown. It can be seen that the adjacent crystal 60 is combined with the intercellular space 62 therein. Since the cleavage plane is oriented in a different direction from the adjacent crystal 60, there is basically no direct path for diamond crushing. This structure allows the PCD material to work well in an overload environment where there is usually a high impact load.

In the process of combining the crystal 60 with a high-temperature and high-pressure press, the intercellular spaces 62 of the crystal 60 are filled with a binder-catalytic material 64. It is this catalytic material 64 that enables the formation of bonds between adjacent diamond crystals 60 in the press at relatively low pressure and temperature.

The prior art PCD element has at least one continuous matrix of mutually bonded crystals 60, which has a number of gaps 62 containing a binder-catalytic material 64, usually cobalt or other group VIII elements. The crystal 60 contains a first diamond continuous matrix, and the gap 62 forms a second gap 62 continuous matrix called the gap matrix 68, which contains the binder-catalytic material. In addition, there needs to be a smaller amount of area where the diamond-diamond growth has already encapsulated part of the binder-catalytic material. These islands are not part of the continuous gap matrix 68 of the binder-catalytic material 64.

See Figures 7 and 9, which are schematic cross-sectional views of the PCD element 2 of the present invention. The PCD element 2 can be made in the same manner as the prior art PCD element described above. In a preferred embodiment, after the pre-cleaning operation or at any time after the manufacturing method, the working surfaces 4, 70, 72 of the PCD element 2 can be partially removed from the adjacent main body. The binder-catalytic material method is used for processing. As a result, the gap 62 between the diamond crystals 60 adjacent to the working surface is substantially free of the catalytic material 64, which is indicated by the mark 66. The portions of the working surfaces 4, 70, 72 that do not contain the catalytic material 64 are not susceptible to thermal degradation encountered in other areas of the PCD, thereby obtaining improved thermal performance.

There are many methods for removing or reducing the catalytic material 64 from the gap 62. In one method, the catalytic material 64 is cobalt or other iron group materials, and the method of removing the catalytic material 64 is from close to the working surfaces 4, 70, 72 of the PCD element 2 in an acid etching process. It is leached in the gap 62 to a depth greater than about 0.2 mm. The method of removing the catalytic material 64 from the proximity of the surface can be achieved by electric discharge, or other electronic or electroplating methods or evaporation methods.

In another method for reducing the catalytic material 64 from the gap 62, the catalytic material 64 may be reduced by chemically combining it with another material, such as alloying, so that it does not It then acts as a catalytic material. In this method, a material may still remain in the interstices of the diamond crystals 60, but the material no longer acts as a catalytic material 64-it is effectively removed.

In yet another method for reducing the catalytic material 64 from the gap 62, the catalytic material 64 is removed by converting it into a material that no longer acts as a catalytic material. This method can be achieved through crystal structure changes, crystal phase changes, mechanical "processing", heat treatment, or other methods. This method can be applied to non-metallic or non-reactive catalytic materials. Moreover, a material can still remain in the gaps 62 of the diamond crystals, but the material no longer acts as a catalytic material 64-effectively removing the catalytic material.

Once the catalytic material 64 adjacent to the working surfaces 4, 70, 72 has become ineffective, the PCD element 2 of the present invention is no longer susceptible to the thermal degradation that often occurs in prior art PCD elements. As mentioned above, there are two known modes of thermal degradation caused by the catalytic material 64. The first thermal degradation mode starts at a temperature as low as about 400° C., and it is due to the different thermal expansion between the catalytic material 64 in the gap 62 and the crystal 60. When fully expanded, the diamond-diamond bond will break, and cracks and fragments will form.

The second thermal degradation mode starts at about 750°C. This mode is caused by the catalytic ability of the binder-catalytic material 64 to contact the crystal 60 and graphitize the crystal 60 at approximately 750°C. When the crystals 60 undergo graphitization, they undergo a large increase in volume, thereby breaking with the main body 4 and no longer bonding. Even a coating of several micrometers of the catalytic material 64 on the surface of the diamond crystal 60 can cause this thermal degradation mode.

Therefore, those skilled in the art should be able to understand that in order to obtain the maximum benefit, the catalytic material 64 must be removed from the gap 62 in the diamond crystal 60 and the surface of the diamond crystal 60. If the catalytic material 64 is removed from both the surface of the diamond crystal 60 and the gap 62, the thermal degradation start temperature of the diamond crystal 60 in this region will reach 1200°C.

However, this dual degradation model provides some unexpected benefits. For example, in many applications, it is desirable to design the wear rate of the working surface. In the present invention, this can be achieved by, for example, changing the treatment method in the area where the maximum wear resistance is required, and the catalytic material can be reduced from the gap 62 and the surface of the diamond crystal 60. In areas where lower abrasion resistance is required, such as in an automatic sharpening tool, these areas should be treated to reduce the catalytic material 64 from the gap 62, but, if not all, may be allowed to partially The diamond crystal 60 still remains in contact with the catalytic material.

It should be clearly seen that the removal from the surface of the diamond crystal 60 is more difficult than the removal of the catalytic material 64 from the gap 62. For this reason, according to the method of reducing the catalytic material adopted to effectively reduce thermal degradation, the depth of the catalytic material 64 is reduced from the working surface 4, and the method for reducing the catalytic material 64 can be reduced according to the method used to reduce the catalytic material 64. And change.

In some applications, it is sufficient to improve the thermal threshold above 400°C but below 750°C. Therefore, a method of reducing the catalytic material 64 with a lower strength is acceptable. As a result, it can be understood that there are a large number of combinations of catalytic material 64 reduction methods that can be applied to obtain the level of catalytic material 64 reduction required for a specific application.

In the present invention, when the term "substantially free" refers to the gap 62, the gap matrix 68, or the volume of the catalytic material 64 in the main body 8, it should be understood that most (if not all) If it is, adjacent to the surface of the diamond crystal 60, there is still a coating of the catalytic material 64. Similarly, when the term "substantially free refers to the catalytic material 64 on the surface of the diamond crystal 60, the catalytic material 64 still exists in the adjacent gap 62.

Since the catalytic material 64 is removed or reduced, the two main mechanisms of thermal degradation will not exist. However, it has been found that the depth to which the catalytic material 64 must be removed should be sufficient to allow the combined crystal 60 to be able to take away the heat generated by the thermal event to be lower than the crystal 60 (where the catalytic material is present) 64) Degradation temperature.

In a series of laboratory tests, heat was input to a PCD element 2 configured as a cutting element 10. Since this test is designed as a standard abrasion test for these cutting elements, it provides an appropriately contrasted cutting element 10 with various depths of the catalytic material 64 removed. In these tests, careful care is required to ensure that the reduction method removes the catalytic material 64 from the gap 62 and from the surface of the diamond crystal 60. The test is designed such that heat that can be repeatedly input is applied to the cutting edge of the PCD cutting element 10 for a known period of time.

Once the test is over, the abrasion index is calculated. The higher the abrasion index, the better the wear resistance. Due to the nature of the test, it is conceivable that an increased abrasion index value indicates that the working surfaces 70, 72 of the cutting element 10 have increased thermal degradation performance.

It can be seen from the curve A in the graph of FIG. 10 that when the reduction depth of the catalytic material 64 reaches 0.1 mm, the wear index of the cutting element 10 results in a significant increase. Therefore, for the type of heat input commonly used in the cutting element 10, when the catalytic material 64 is removed from the gap 62 and from the surface of the diamond crystal 60, the depth of 0.1 mm is the distance from the working surface 4, 70. , 72 critical reduction depth.

In other tests, when the cutting element 10 is made by a more economical method for removing the catalytic material 64, it is considered that the relationship of the relative reduction depth of the wear is as shown in the curve "B" in FIG. 10. The method of reducing the catalytic material 64 used in these cutting elements is not as effective as the method of curve "A" for removing the catalytic material 64 from the surface of the diamond crystal 60. Therefore, it is not effective until most of the catalytic material 64 is removed from the gap 62 to a depth of about 0.2 mm, where the wear rate increases to the level of the curve "A".

It can be considered that in some favorable places, the thermal degradation related to the wear rate as shown in the curve "C" of FIG. 10 can be designed into the PCD element 2. For example, it is desirable to make the edges of the curved cutting element 10 away from the center of contact wear faster than the center point. This will tend to maintain the curved shape of the cutting element instead of making it a flat surface.

Improved resistance to thermal degradation can improve the wear rate, because diamond is an extremely good heat conductor. If a frictional event on the working surface 4, 70, 72 causes a sudden large heat input, the bonded diamond crystal will conduct the heat in all directions away from the event. This will allow a very high temperature gradient in the material, possibly 1000°C/mm or higher. Such a steep gradient will enable the working surfaces 4, 70, 72 to reach 950°C, but will not cause significant thermal degradation (if the distance from the heat source is just 0.2mm deep, the gap 62 and adjacent to the working surface When the surface of the diamond crystal 60 is substantially free of the catalytic material 64).

It should be clear that the temperature gradient will vary according to the size of the crystal 60 and the amount of bonding between the crystals. However, in the field test of the cutting element 10 for earth-boring bits, substantially all the catalytic material 64 is removed from the gap 62 to a distance D of about 0.2-0.3 mm from a working surface 4, 70, 72, Significant improvement can be obtained in grinding, the penetration rate is increased by 40%, and the wear resistance is increased by 40%. The improvement in the wear resistance indicates that the wear of the diamond crystal 60 is greatly reduced due to the thermal degradation caused by the catalytic material 64. The increased penetration rate is believed to be attributable to the ability of the cutting element to retain the "abrasive tool" for a longer period of time due to increased wear resistance.

There are other possible PCD element configurations that can benefit from the reduction or removal of the catalytic material 64 as described above. As shown in FIGS. 11A, 11B, and 11C, another embodiment of the present invention is a composite PCD element 102. The PCD element 102 has a main body 108 with a Group VIII binder-catalytic material as a second prefabricated PCD element 110 embedded therein. The embedded PCD element 110 may be flush with the working surface 104 of the packaged PCD element 120, as shown in FIG. 11A, or it may be entirely embedded in the packaged PCD element 120, as shown in FIG. 11B. This embedded PCD element 110 is made in a method that uses powdered carbonate of Mg, Ca, Sr and Ba as the binder-catalytic material, and it is made into a composite PCD element , As described in co-assigned pending U.S. Patent Application No. 09/390074, which is incorporated herein by reference.

In this embodiment, since the embedded prefabricated PCD element 110 is formed under a higher pressure, the diamond density can be made higher than the density of the packaged PCD element 120. In this configuration, since the embedded PCD element 110 has a catalytic material with a higher active temperature, for example, they can be advantageously used to reduce the catalytic material in only the working surface of the packaged PCD element 120 . Moreover, the embedded PCD element 110 can be placed in the packaged PCD element 120 to take full advantage of the higher impact resistance of the embedded PCD element 110 and the improved wear resistance of the packaged element 120.

As shown in FIGS. 9, 11A, 11B, and 11C, the element 102 has a large number of partially bonded diamond crystals 60, a catalytic material 64 and a main body 108 with a working surface 104. The volume 112 of the main body adjacent to the working surface 104 has a diamond density significantly higher than other places 114 in the main body 108, and the volume 112 is substantially free of the catalytic material 64.

A plurality of embedded PCD elements 110 may be arranged in the composite element 100, as shown in FIG. 11C, they are arranged in such a way that the best impact performance and improved wear performance can be obtained.

It is desirable to reduce the catalytic material embedded in the PCD element 110 and the catalytic material in the encapsulated PDC element 120. This combination will provide a component that has the highest possible impact strength and the highest possible wear resistance that can be obtained in commercial diamond components.

In FIGS. 12A and 12B, a PCD element 202 according to another embodiment of the present invention is shown. In this embodiment, the PCD element 202 is first manufactured according to the prior art method. After a surface has been made, a CVD or PVD method is used to provide a series of closely packed epitaxially oriented diamond crystals 260 which are deposited on a future working surface 204 on a portion 210 of the PCD element 202. The component is then subjected to high pressure and high temperature treatment, so that the deposited diamond crystal 260 and the diamond crystal in the original PCD form a diamond-diamond bond with each other. This diamond-diamond bond may be due to the presence of the catalytic material 64 immersed from the surface of the original PCD element 202.

After being cleaned, a portion of the working surface 204 is processed to reduce the catalytic material 64 from the CVD or PVD deposited layer. The final product is a PCD element that has a part of the working surface 204 whose volume 214 has a diamond density greater than the density of the other surfaces 280 of the PCD element 202. This high diamond density area 214 then reduces the catalytic material 64. The other surface parts of the PCD element 202 can also reduce the binder catalytic material.

Generally, the elements 102, 202 shown in FIGS. 11A, 11B, 11C, 12A, and 12B can be labeled as PCD elements 102, 202, and they have a main body 108, 208 with a working surface 104, 204. The density of diamonds adjacent to the working surfaces 104 and 204 is significantly higher than the density of other places in the main body 108 and 208, and is substantially free of the catalytic material 64.

A particularly useful application of the PCD element 2 of the present invention is the cutting elements 10, 50, 52 as shown in FIGS. 1B, 4, and 5. The working surface of the PCD cutting element 10, 50, 52 may be a vertex working surface 70 and/or a peripheral working surface 72. The PCD cutting element 10 shown in FIG. 1B is such an element, which can be typically used in a fixed cutting edge type rotary drill bit 12, or in a gauge drill bit of other types of drilling tools. The PCD cutting element 50 shown in FIG. 5 can be formed into a dome shape 39. This type of PCD cutting element has an extension base 51 for inserting into a socket in the main body of a roller cone bit 38 or two rotary drill bits 12, 38, which will be described in detail below .

The PCD cutting element 52 shown in FIG. 4 is suitable for use in a machining method. Although the configuration of the cutting element 52 shown in FIG. 4 is rectangular, those skilled in the art should understand that such elements can be triangular, quadrilateral, or many other types suitable for processing highly abrasive products that are difficult to process with conventional tools. shape.

The PCD cutting element 10 may be a prefabricated cutting element 10 with a fixed cutting edge and rotating drill bit 12 (as shown in FIG. 2). The bit body 14 of the drill bit is formed by a large number of scrapers 16, which generally extend outward from the longitudinal axis 18 of the center of rotation of the drill bit. Spaced side by side along the front face 20 of each blade is a large number of PCD cutting elements 10 according to the present invention.

Typically, the PCD cutting element 10 has a body in the form of a small circular piece, which has a thin front facing surface 30 of the diamond or diamond-like carbon (PCD) material, which is bonded to a high-pressure high-temperature press. A low-hardness material such as bonded tungsten carbide substrate 32. The cutting element 10 is prefabricated and then usually bonded to a substantially cylindrical support 34. The support can also be formed of bonded tungsten carbide, or, as an alternative, it can be directly connected to The scraper. The PCD cutting element 10 has working surfaces 70 and 72.

The cylindrical support 34 is received in a correspondingly shaped socket or groove of the scraper 16. The support 34 is usually installed in the socket by welding or hot pressing. In operation, the fixed cutting edge bit 12 rotates and applies weight. This will force the cutting element 10 into the ground to be drilled, thereby achieving cutting and/or drilling.

The PCD cutting element 10 can also be applied to the gauge region 36 of the drill bit 12 to provide a metering reaming effect and protect the drill bit 12 from excessive wear in the gauge region 36. In order to space these cutting elements 10 as close as possible, it is ideal to cut these elements into a shape such as the rectangular shape shown, and they will be easier to install in the metering area 36.

In the second embodiment, the cutting element 50 (as shown in FIG. 5) of the present invention is located on the roller cone bit 38 as shown in FIG. The roller cone bit 38 typically has one or more truncated rolling cone cutters 40, 41, 42 which are arranged on a support shaft on the strut 44 of the bit body 46. The cutting element 50 may be installed as a large number of one or more of the cutting inserts arranged in rows on the rolling knives 40, 41, 42, or, alternatively, the The PCD cutting element 50 may be arranged along the strut 44 of the drill bit 38. The PCD cutting element 50 has a main body in the form of a veneer surface 35 of diamond or diamond-like material bonded to a low-hardness base 37. In this embodiment of the invention, the facing surface 35 is in the form of a dome surface 39 and has working surfaces 70 and 72. Therefore, there are often multiple transition layers between the facing surface 35 and the base 37 to help more uniformly disperse the stress generated during the manufacturing process, which are well known to those skilled in the art.

In operation, the roller cone bit 38 rotates and applies weight. This will force the insert cutter 50 in the row of rolling cone cutters 40, 41, 42 into the ground, and when the drill bit 36 rotates, the rolling cutters 40, 41 , 42 rotates, so as to achieve the role of drilling.

In another embodiment, the PCD cutting element 52 of the present invention is a triangular, rectangular, or other shape material suitable for inserting blank cutters in machining operations. In this embodiment, the cutting element 52 has a main body, which is in the form of a veneer surface 54 of diamond or diamond-like material bonded to a low-hardness matrix 56 having working surfaces 70 and 72 . Typically, the cutting element 52 will then be cut into a large number of smaller pieces, which are then attached to an insert 58 (which is installed in a tool holder of a machine tool). The cutting element 52 can be connected to the insert by brazing, bonding, welding or clamping. In a high temperature and high pressure manufacturing method, it is also feasible to finally make the cutting element 52 into the shape of the insert.

As shown in Figures 13-18, the PCD element 2, 102, 202 of the present invention can also be used in other applications, such as a hollow mold, for example, used as a drawing die. In Figure 13, a PCD element 302 of the present invention is used Of 300. It is also feasible to use the excellent heat transfer performance and electrical insulation performance of the PCD elements 2, 102, 202 as the heat sink 310 with the PCD element 312 of the present invention.

Other applications include a friction bearing 320 with a PCD bearing element 322, as shown in Fig. 15, and fittings for valves 340, 344 having a surface 342 of the PCD element 342 of the present invention, as shown in Figs. 16A and 16B. In addition, the indenter 360 used for scribing, durometer, surface roughing, etc. may also have the PCD element 362 of the present invention as shown in FIG. 17A. The punch 370 may also have one or two dies 372 and 374 made of the PCD material of the present invention, as shown in FIG. 17B. Moreover, the machine tool spindle 382 and other types of wear components used in the measuring device 380, as shown in FIG. 18, can also be made of the PCD components of the present invention. It should be understood that almost every application of polycrystalline diamond will benefit from the PCD element with reduced catalytic material of the present invention.

Although the present invention has been described with reference to the drawings, it should be understood that within the scope and spirit of the present invention, in addition to those already given or suggested herein, other and additional improvements can also be made.