Magnetisable brilliant pigments.

p0001The present invention relates to novel magnetizable luster pigments based on coated, platelet-shaped, nonferromagnetic, metallic substrates having<ul><li>A) a first, ferromagnetic layer comprising γ-Fe₂O₃, and optionally</li><li>B1) a further, nonferromagnetic, metallic oxide-containing layer and / or</li><li>B2) an outer, passivating, phosphate-, chromate and / or vanadate-containing layer.</li></ul>

p0002Moreover, the invention relates to mixtures of these pigments and with a ferromagnetic, γ-Fe₂O₃ containing layer and if desired an additional metal oxide layer and / or an outer, passivating, phosphate-, chromate- and / or vanadate-containing layer occupied silicatic platelets which have already been in a first layer can be coated with metal oxide.

p0003Furthermore, the invention relates to the preparation of these pigments and pigment mixtures and to their use for coloring paints, printing inks, plastics, glasses, ceramic products and decorative cosmetic preparations.

p0004Luster or effect pigments are increasingly used in many fields of technology, for example in automotive coatings, decorative coatings, plastics pigmentation, paints, printing inks, especially security printing inks, and cosmetics.

p0005Their optical effect is based on the directed reflection of light at predominantly sheetlike, mutually parallel-oriented, metallic or strongly refractive pigment particles. Depending on the composition of the pigment platelets, interference, reflection and absorption phenomena create angle-dependent color and lightness.

p0006Condition for specular reflection is the alignment of the platelet-shaped pigments in the application medium. In paints and printing inks, this alignment is usually done by flow processes within the binder during application. Shrinking processes that occur, for example during drying of thin paint films, improving the uniform alignment of the pigment platelets additionally.

p0007However, special optical effects can be achieved by different pigment orientations in different areas of the application medium. For example, in the coloring of plastics injection molding to observe flowlines that are visualized by differently oriented pigment flakes.

p0008Interesting three-dimensional optical effects arising for example when using magnetizable pigment flakes by exposure to magnetic fields during or after application in the still liquid application medium. Magnetizable luster pigments are therefore for a number of applications such as security printing, as magnetically readable code, or for artistic and decorative purposes are of particular interest.

p0009As magnetizable luster pigments, such pigments are suitable in principle, in which platelet-shaped, ferromagnetic substrate such as iron or nickel, which can be uncoated or coated with metal oxide, are present or where a non-ferromagnetic, platelet-shaped substrate is coated with magnetizable layers.

p0010In the DE-A-23 13 331 and 39 38 055 magnetizable glossy pigments are called on the basis of coated magnetite mica. From US-A-3536520 and JP-A-161 055/1982 are nickel coated mica known.

p0011Magnetizable luster pigments with platelet, non-ferromagnetic, metallic substrate are described only in the older, non-prepublished DE-A-42 17 511th Here, however, the metal substrate, particularly aluminum, first coated with a first, non-magnetizable metal oxide layer, and only then followed by the magnetizable layer of magnetite, iron, cobalt or nickel, and if desired a further oxidic cover layer.

p0012The magnetizable luster pigments based on coated mica the low coverage is due to the transparent substrate material disadvantage. Whilst additional magnetite, nickel or cobalt layers increase the opacity of these pigments, however, can be metal-like luster and color strength with increasing thickness of the ferromagnetic layer to.

p0013When using ferromagnetic substrates, such as nickel or iron flakes for the preparation of magnetizable luster pigments, there is the problem of lack of availability, so that an economical manufacture is made more difficult. In addition, the processing of these pigments is complicated by their high specific gravity.

p0014The invention was therefore the object of providing new magnetizable luster pigments without the disadvantages mentioned and with advantageous application properties.

p0015Accordingly, the above-defined magnetizable luster pigments and their mixtures were magnetized coated silicatic platelets found.

p0016In addition, a process for the preparation of these pigments has been found which is characterized in that the metallic substrate in a fluidized bed<ul><li>a1) initially occupied by gas phase decomposition of iron carbonyl in the presence of steam and / or oxygen at a substantially containing magnetite layer and this layer is then converted by heating the pigment in an oxidizing atmosphere into a ferromagnetic, γ-Fe₂O₃ containing layer or</li><li>a2) initially occupied by gas phase decomposition of iron carbonyl in the presence of oxygen and / or steam with a substantially α-Fe₂O₃ containing layer, this layer by heating in a reducing atmosphere in an iron (II) containing layer and the reduced layer then by heating in transferred to an oxidizing atmosphere into a ferromagnetic, γ-Fe₂O₃ containing layer and if desired</li><li>b1) subsequently by gas phase decomposition of volatile metal compounds in the presence of oxygen and / or water vapor with a further layer of non-ferromagnetic metal oxide, and / or </li><li>b2) by gas phase decomposition of vaporizable phosphorus, chromium and / or vanadium compounds in the presence of steam with an additional, passivating, phosphate-, chromate and / or vanadate-containing layer.</li></ul>

p0017Furthermore, a process for preparing the luster pigment mixtures has been found which is characterized in that the metallic substrate and the uncoated or already metal oxide-coated silicatic platelets together in a fluidized bed by gas phase decomposition according to step a1) or a2), and optionally b1) and / or b2) assigned to the desired layers.

p0018Finally, a method for coloring paints, printing inks, plastics, glasses, ceramic products and decorative cosmetic preparations has been found which is characterized in that this luster pigments or luster pigment mixtures of the invention used.

p0019Moreover, a special embodiment of this method has been found which is characterized by exposing the luster pigments during or after application in the still liquid application medium to a magnetic field.

p0020For the pigments of the invention all non-ferromagnetic, metallic effect pigments known for metals and alloys are suitable as the substrate in a plate form. Examples besides copper and its alloys such as brass and bronzes include in particular aluminum and its alloys such as aluminum bronze.

p0021Preferably aluminum flakes which are producible in a simple manner by stamping out of aluminum foil or by known atomization and grinding techniques.

p0022The size of the substrate is not critical per se and can be adapted to the respective application. As a rule, the particles have mean largest diameters from about 1 to 200 microns, particularly about 5 to 100 microns, and thicknesses of about 0.1 to 5 .mu.m, in particular by about 0.5 microns.

p0023Commercially available products are used. However, the surface of the aluminum should be substantially free of fats or other means. These substances can be removed by oxidative treatment in part, by solvent treatment or better, as described in the older, not previously published DE-A-42 23 384.

p0024The magnetizable luster pigments of the invention, the substrate having a ferromagnetic layer (A) containing γ-Fe₂O₃ (maghemite) is occupied. The layer (A) can be advantageously applied by gas phase decomposition of iron carbonyl in the presence of steam and / or oxygen essentially to magnetite and its subsequent oxidation to γ-Fe₂O₃ to the substrate. In this smooth, homogeneous and the substrate evenly enveloping layers are obtained.

p0025An alternative preparation route is to first apply by oxidative gaseous phase decomposition of iron carbonyl a layer consisting essentially of α-Fe₂O₃ layer to convert these by heating in a reducing atmosphere containing a iron (II) layer, and the reduced layer to the layer (A) to oxidize.

p0026The thickness of the layer (A) is not critical per se and is generally 1 to 500 nm, preferably 5 to 200 nm.

p0027Due to the inherent color of red γ-Fe₂O₃ pigments of the invention are particularly useful for the red to yellow color range of interest. Golden hues are already at a layer thickness (A) of generally 10 to 40 nm was obtained (corresponding to a Maghemitgehalt of about 15 to 20 wt .-%), brilliant reds arise primarily with layer thicknesses (A) of usually 80 to 130 nm (Maghemitgehalt of about 45 to 55 wt .-%, based on the coated pigment).

p0028Since the production in particular of red pigments due to the high flammability of the reaction mixture by inserting the thermite reaction is problematic, it is advantageous to coat mixtures of aluminum flakes, and silicate flakes, whereby ignition can be effectively avoided (s. Also DE-A- 42 09 242).

p0029Suitable silicatic substrates for this particular light-colored or white micas, and flakes of preferably wet-ground muscovite are particularly preferred. Of course, other natural micas such as phlogopite and biotite, artificial mica, talc and glass flakes are suitable.

p0030The used next silicatic substrate may already in a first layer with metal oxides such as chromium, tin, zinc, aluminum, silicon oxide, bismuth oxychloride, preferably iron (III) oxide and zirconium dioxide, titanium dioxide is particularly preferably. These pigments are generally known and also under the names Iriodin® (Merck, Darmstadt), Flonac® (Kemira Oy, Pori) or Mearlin® (Mearlin Corp., New York) in the trade.

p0031The composition of the luster pigment mixtures according to the invention of magnetizable, metallic luster pigments (I) and magnetizable silicate luster pigments (II) is in itself not critical, but depends on the desired color properties of the pigment mixture. Further, each of the two components should be contained at least 5 wt .-%, on the one hand, the opacity, but on the other hand, to ensure the safety.

p0032Advantageous magnetizable red pigments with metallic luster and good hiding power resulting for instance in the allocation of an aluminum / muscovite mixture with an aluminum content of 5 to 50 wt .-% with usually 20 to 55 wt .-% maghemite, based on the substrate.

p0033To protect the layer (A) to environmental influences luster pigments of the invention with a second, non-ferromagnetic, metal-containing layer can be assigned. Particularly suitable for this purpose are colorless metal oxides such as silica, zirconia, titania and alumina, conceivable, however, are also colored metal oxides such as α-Fe₂O₃.

p0034The thickness of layer (B1) is not critical and is generally 1 to 500 nm, preferably 5 to 200 nm.

p0035To increase the stability of the luster pigments of the invention in aqueous systems, occupied on a layer (A) and optionally also with a layer (B1) pigments can by Gasphasenpassivierung an additional, phosphate-, chromate and / or vanadate-containing layer (B2 ) are applied, wherein a phosphate-containing coating is preferred. This passivation is particularly recommended for aluminum pigments that are to be used in aqueous systems, for example, water-based paints.

p0036In the method for producing the magnetizable luster pigments of the invention, the individual coatings are made in the gas phase in each case by decomposition of suitable starting compounds in the presence of about occupying substrate. Depending on the type of coating different starting compounds and reaction conditions are required.

p0037The coating can be advantageously carried out in a heatable fluidized bed reactor, as described for example in EP-A-45 581. The substrate (the metal flakes or their mixtures with silicatic platelets) are initially fluidized with a fluidizing gas and heated 70 to 350 ° C generally to the required for the decomposition of the respective metal compound temperature. The vaporized metal compounds and optionally required for the decomposition gases are then introduced via separate nozzles. This is expediently carried out using an inert carrier gas such as argon, especially nitrogen, which is routed via appropriate, the reactor upstream evaporator templates with the respective metal compound or the water or the reaction gas (air or oxygen) is mixed.

p0038In order to obtain the substrate uniformly and completely enveloping, homogeneous layers, the gas amount of the metal compound is generally not more than 5 vol .-%, should preferably amount to no more than 2 vol .-% of the total amount of gas in the reactor. This applies to both step a) and for step b) of the process according to the invention.

p0039The availability of the substrate particles with ferromagnetic, γ-Fe₂O₃ containing layer (A) can be done in various ways.

p0040In the variant a1) a layer consisting essentially of magnetite layer is first by selective oxidation of iron carbonyl, in particular iron pentacarbonyl, is applied, which is subsequently converted by oxidation in the layer (A).

p0041The oxidation of the iron carbonyl can be carried out by steam and / or oxygen.

p0042Preferably, the reaction with water vapor is usually at 170 to 350 ° C, preferably 180 to 250 ° C, which can be described by the following reaction equation:         3Fe (CO) ₅ + 4H₂O → Fe₃O₄ + 4H₂ + 15CO The molar ratio of water to carbonyl iron should be at least the stoichiometric ratio of 1.33: match. 1 Since the magnetite formed is not attacked under the coating conditions of water vapor, the water vapor content in the fluidized gas is not critical. It is therefore generally 10 to 100 times the stoichiometric amount of water required a.

p0043The oxidation of the iron carbonyl can also be made directly with oxygen or air. Here, however, oxygen and carbonyl must as accurately as possible in a stoichiometric ratio (about 1.33: 1) are introduced into the reaction chamber to avoid further oxidation to α-Fe₂O₃. Suitable reaction temperatures are here usually 170-350 ° C.

p0044After completion of assignment with the magnetite layer is cooled the reactor expediently first to room temperature and then the fluidizing gases for passivating pyrophoric any existing shares in the applied layer to some air.

p0045The subsequent oxidation of the magnetite to γ-Fe₂O₃ can be both in fluidized bed reactor than in another heated apparatus, for example a batch furnace perform. In both cases, the oxidation easy to use air. Of course, other oxygen / inert gas mixtures are suitable.

p0046The pigment is thereby heated expediently slowly to the desired oxidation temperature. The heating rate depends of the iron oxide content of the pigment from, especially at high levels (about 35 to 55 wt .-%) should be a small heating rate can be selected. Typical heating rates are about 10 to 100 ° C / h.

p0047The oxidation temperature is generally 100 to 600 ° C, preferably 180 to 400 ° C. and more preferably 200 to 350 ° C.

p0048The oxidation is usually completed in 8 to 24 h, while thick layers require the longer oxidation times.

p0049With increasing oxidation temperature and oxidation time, the layer formed (A) in addition to γ-Fe₂O₃, increasingly, α-Fe₂O₃. But also pigments with a lower proportion of the layer (A) of γ-Fe₂O₃ are still magnetically aligned.

p0050In the variant a2) for the application of the ferromagnetic layer (A) is first prepared by oxidation of iron carbonyl, especially iron pentacarbonyl, one applied essentially of α-Fe₂O₃ existing layer, which is then converted by reduction into an iron (II) -containing layer. This layer is subsequently converted by oxidation into γ-Fe₂O₃ containing layer (A).

p0051The oxidation of the iron carbonyl is advantageously as described in EP-A-33 457, by oxygen or air or other oxygen / inert gas mixtures, in which water vapor on or may be absent. In contrast to the targeted production of magnetite Fe₃O₄ is no problem of a possible oxidation.

p0052The layer obtained, essentially consisting of α-Fe₂O₃ is then by heating in a reducing atmosphere, that is advantageously in the presence of eg carbon monoxide or especially hydrogen, as well as mixtures thereof, to the iron (II) -containing layer, as essential components iron (II) oxide, containing magnetite and iron, is converted.

p0053Cheap reduction temperatures are generally from 200 to 600 ° C, preferably 200 to 400 ° C.

p0054The heating rate is usually about 10 to 50 ° C / h. The reduction is usually completed in 8 to 24 h.

p0055As described in the production of the magnetite layer, the reactor is then expediently first cooled to room temperature, then the fluidizing gases for passivating pyrophoric any existing shares in the reduced layer is admixed with some air.

p0056The subsequent oxidation of the iron (II) containing layer to the layer (A) can be carried out similarly to the procedure described in variant a1).

p0057If after the ferromagnetic layer (A) or a metal oxide layer (B1) and / or a passivating layer (B2) is applied, so the product when carrying out the oxidation in fluidized bed reactor need not be isolated as an intermediate, but the further layer can advantageously directly subsequently by lowering the temperature and replacement of the fluidizing gas are performed in the same reactor. If the oxidation carried out in a chamber furnace, so the product is of course until re-transferred to a fluidized bed reactor.

p0058For the deposition of a further layer (B1) of non-ferromagnetic metal oxides are used as volatile metal compounds preferably have the carbonyls, the alcoholates, both aromatic and phenolates and Benzylalkoholate and aliphatic, in particular C₁-C₄-alkoxides, such as n-, iso- and tert butoxides, ethoxides and methoxides preferably and particularly preferably n- and iso-propoxides and the halides used.

p0059Examples of preferred metal compounds are titanium, zirconium tetra-n- and isopropoxide, Siliciumtetraethanolat and Aluminiumclorid and iron pentacarbonyl.

p0060The hydrolysis of the alkoxides with water vapor is preferably carried out in the absence of oxygen. At least the stoichiometrically required to form the desired oxide amount of steam to be supplied, but you can also work with a slight excess. With this assignment is preferably an inert gas such as nitrogen as the fluidizing gas. Suitable hydrolysis temperatures are generally from 100 to 350 ° C, preferably 150 to 250 ° C.

p0061In particular for use in aqueous systems, it is advisable to passivation of a layer (A) and optionally also a layer (B1) coated pigments by applying an additional, phosphate-, chromate- and / or vanadate-containing layer (B2), said phosphate-containing layers (B2) are particularly preferred.

p0062The passivation may be as described in the older, not previously published DE-A-42 36 332, advantageously be carried out by gas phase decomposition of vaporizable phosphorus, chromium and / or vanadium compounds in the presence of water vapor.

p0063Very good water resistance arising in the hydrolytic decomposition of the vaporized phosphorus-containing compounds, in particular derived from the oxo acids of phosphorus.

p0064Among these, the tri and di (C₁-C₄-alkyl) esters of phosphoric acid and the tri- and di- (C₁-C₂-alkyl) esters of phosphorous acid are particularly preferred. Examples include the esters (RO) ₃PO (R = methyl, ethyl, propyl, iso-propyl, butyl or iso-butyl), and (RO) ₂PO (OH) (R = methyl, ethyl) and (RO) ₃P and ( RO) ₂P (OH) (R = methyl, ethyl) mentioned.

p0065Also very suitable are the phosphorus oxyhalides POX₃ with X = identical or different halogens. Preferred examples are here: POCl₃, POBrCl₂, POBr₂Cl and POBr₃.

p0066Furthermore, also vaporizable Oxychloride of other metals, particularly chromyl (CrO₂Cl₂) and also Vanadiumoxidchlorid (VOCl₃) are.

p0067When Gasphasenpassivierung, the usual procedure so that it fluidizes the substrate with an inert gas such as nitrogen and a portion of the fluidizing gas through a reactor upstream evaporator template with the corresponding phosphorus, chromium and / or vanadium compounds and another part of the fluidized gas over a-fed with water vaporizer vessel with steam loads.

p0068Here, the gas amount of the phosphorus, chromium and / or vanadium compound usually should not be more than 3 vol .-%, preferably 0.001 to 0.5 vol .-% of the total amount of gas be in the reactor.

p0069The amount of the added water vapor depends on the concentration of the passivating species and should be at least the stoichiometrically required amount correspond; preference is given to 10 to 100 times the molar amount of water vapor.

p0070In general, the passivation at 100 to 350 ° C is carried out. In a phosphating from phosphorus oxychloride, for example, the reaction temperature is preferably 130 to 220 ° C.

p0071As usual, covered with a passivating layer pigments can be removed from the reactor after cooling.

p0072Using the method, the new luster pigments and luster pigment mixtures can be prepared in a simple and reproducible manner again. The pigments obtained are characterized by high quality of the coating, ie homogeneous, uniform and the substrate film-like enveloping layers of.

p0073The magnetizable luster pigments and luster pigment mixtures of the invention are advantageously useful for many purposes such as for coloring paints, printing inks, plastics, glasses, ceramic products and decorative cosmetic preparations. They show high gloss, attractive colors, and good coverage and are due to its ferromagnetic properties for special applications such as the generation of three-dimensional optical effects by the application of magnetic fields during or after application while still fluid application medium suitable. For example, the safety and Security printing may be mentioned; Holograms on credit card can be for example replaced with cheaper, equally effective, aligned by magnetic luster pigments.

Examples

Preparation of magnetizable luster pigments and luster pigment mixtures according to the invention

p0074The coatings of the substrate particles described in the examples were each in an externally heatable fluidized bed reactor made of glass with a diameter of 8 cm and a height of 80 cm with glass frit bottom and top hinged, with a nitrogen jet abreinigenden filter stockings and two laterally inserted above the frit bottom nozzle performed for gas introduction.

p0075To evaluate the magnetic properties of the pigments obtained were the saturation magnetization M_s [NTm³ / g], the remanence M_r [NTm³ / g] and the coercive force H_c [KA / m] measured with a vibrating sample magnetometer.

example 1

p0076200 g of a commercial, finely divided aluminum pigment (BET surface area 4.5 m² / g, average particle diameter 20 microns) were in the fluidized bed reactor under fluidization with a total of 800 l / h of nitrogen heated to 190 ° C. In this half of the nitrogen via a was heated to 60 ° C warmed template with water and the other half on a held to room temperature template directed with iron pentacarbonyl. 60.7 g of iron pentacarbonyl were within about 8 hours so fed.

p0077During subsequent cooling of the reactor to the fluidized gas for passivating pyrophoric shares of magnetite layer formed was admixed with a little air.

p0078The resulting strong metallic luster displayed pigment had an iron content of 5.5 wt .-%.

p0079For conversion of magnetite in a γ-Fe₂O₃ layer containing the pigment was then heated to a ceramic insert in a box furnace within 2.5 h at 250 ° C and held for 12 hours at this temperature.

p0080After cooling, a very shiny, brass-colored pigment whose magnetic properties are shown in Table 1, (Sample 1).

p0081A further sample of the magnetitbeschichteten pigment was heated to 400 ° C within 4 hours and heated at this temperature for 15 h.

p0082Here, a very shiny, gold-colored pigment was obtained (sample 2), whose magnetic properties are also shown in Table 1 below. <tables id="tabl0001" num="0001"><table frame="all"><title>Table 1</title><tgroup cols="6" colsep="1" rowsep="1"><colspec colnum="1" colname="col1" colwidth="26.25mm" /><colspec colnum="2" colname="col2" colwidth="26.25mm" /><colspec colnum="3" colname="col3" colwidth="26.25mm" /><colspec colnum="4" colname="col4" colwidth="26.25mm" /><colspec colnum="5" colname="col5" colwidth="26.25mm" /><colspec colnum="6" colname="col6" colwidth="26.25mm" /><thead valign="top"><row><entry namest="col1" nameend="col1" /><entry namest="col2" nameend="col2" align="center">Temp. [° C]</entry><entry namest="col3" nameend="col3" align="center">hue</entry><entry namest="col4" nameend="col4" align="center">M_s[NTm³ / g]</entry><entry namest="col5" nameend="col5" align="center">M_r[NTm³ / g]</entry><entry namest="col6" nameend="col6" align="center">H_c[came]</entry></row></thead><tbody valign="top"><row><entry namest="col1" nameend="col1" align="left">before Ox.</entry><entry namest="col2" nameend="col2" align="center">-</entry><entry namest="col3" nameend="col3" align="left">silver</entry><entry namest="col4" nameend="col4" align="char" char=",">3.5</entry><entry namest="col5" nameend="col5" align="char" char=",">0.3</entry><entry namest="col6" nameend="col6" align="char" char=",">8.5</entry></row><row><entry namest="col1" nameend="col1" align="left">sample 1</entry><entry namest="col2" nameend="col2" align="center">250</entry><entry namest="col3" nameend="col3" align="left">Brass</entry><entry namest="col4" nameend="col4" align="char" char=",">4.4</entry><entry namest="col5" nameend="col5" align="char" char=",">0.1</entry><entry namest="col6" nameend="col6" align="char" char=",">1.4</entry></row><row><entry namest="col1" nameend="col1" align="left">sample 2</entry><entry namest="col2" nameend="col2" align="center">400</entry><entry namest="col3" nameend="col3" align="left">gold</entry><entry namest="col4" nameend="col4" align="char" char=",">3.1</entry><entry namest="col5" nameend="col5" align="char" char=",">0.1</entry><entry namest="col6" nameend="col6" align="char" char=",">0.8</entry></row></tbody></tgroup></table></tables>

p0083In the application in varnish, the pigment flakes of all samples oriented by the action of a magnetic field in the still wet paint film along the field lines. In dried paint resulted in this way three-dimensional structures.

example 2

p0084A mixture of 100 g of commercially available, finely divided aluminum pigment (BET surface area 4.5 m² / g, average particle diameter 20 microns) and 100 g of TiO₂-coated mica pigment (Irodin® 9103 Sterling Silver WR, Merck) was in the fluidized bed reactor under fluidization with a total of 800 l / h of nitrogen heated to 190 ° C. In this half of the nitrogen via a was heated to 60 ° C warmed template with water and the other half on a held to room temperature template directed with iron carbonyl. 110 g carbonyl iron were within about 16 hours so fed.

p0085During subsequent cooling of the reactor to the fluidized gas for passivating pyrophoric shares of magnetite layer formed was admixed with a little air.

p0086The thus produced metallic luster pigment had an iron content of 9 wt .-%, was darker from Example 1 compared to magnetitbeschichteten pigment and showed a weak Braunton (magnetic values ​​in Table 2 against oxidation).

p0087Several samples of the magnetitbeschichteten pigment mixture were heated in a box furnace with a heating rate of 50 ° C / h to a temperature between 250 and 400 ° C and heat-treated at the respective temperatures for 15 h.

p0088Table 2 gives an overview of the results of these experiments. <tables id="tabl0002" num="0002"><table frame="all"><title>Table 2</title><tgroup cols="6" colsep="1" rowsep="1"><colspec colnum="1" colname="col1" colwidth="26.25mm" /><colspec colnum="2" colname="col2" colwidth="26.25mm" /><colspec colnum="3" colname="col3" colwidth="26.25mm" /><colspec colnum="4" colname="col4" colwidth="26.25mm" /><colspec colnum="5" colname="col5" colwidth="26.25mm" /><colspec colnum="6" colname="col6" colwidth="26.25mm" /><thead valign="top"><row><entry namest="col1" nameend="col1" /><entry namest="col2" nameend="col2" align="center">Temp. [° C]</entry><entry namest="col3" nameend="col3" align="left">hue</entry><entry namest="col4" nameend="col4" align="center">M_s[NTm³ / g]</entry><entry namest="col5" nameend="col5" align="center">M_r[NTm³ / g]</entry><entry namest="col6" nameend="col6" align="center">H_c[came]</entry></row></thead><tbody valign="top"><row><entry namest="col1" nameend="col1" align="left">before Ox.</entry><entry namest="col2" nameend="col2" align="center">-</entry><entry namest="col3" nameend="col3" align="left">dark</entry><entry namest="col4" nameend="col4" align="char" char=",">17.9</entry><entry namest="col5" nameend="col5" align="char" char=",">4.3</entry><entry namest="col6" nameend="col6" align="char" char=",">39.1</entry></row><row><entry namest="col1" nameend="col1" align="left">sample 1</entry><entry namest="col2" nameend="col2" align="center">250</entry><entry namest="col3" nameend="col3" align="left">green gold</entry><entry namest="col4" nameend="col4" align="char" char=",">15.2</entry><entry namest="col5" nameend="col5" align="char" char=",">3.5</entry><entry namest="col6" nameend="col6" align="char" char=",">25.4</entry></row><row><entry namest="col1" nameend="col1" align="left">sample 2</entry><entry namest="col2" nameend="col2" align="center">300</entry><entry namest="col3" nameend="col3" align="left">gold</entry><entry namest="col4" nameend="col4" align="char" char=",">14.5</entry><entry namest="col5" nameend="col5" align="char" char=",">3.4</entry><entry namest="col6" nameend="col6" align="char" char=",">25.0</entry></row><row><entry namest="col1" nameend="col1" align="left">sample 3</entry><entry namest="col2" nameend="col2" align="center">350</entry><entry namest="col3" nameend="col3" align="left">gold</entry><entry namest="col4" nameend="col4" align="char" char=",">13.5</entry><entry namest="col5" nameend="col5" align="char" char=",">3.0</entry><entry namest="col6" nameend="col6" align="char" char=",">24.9</entry></row><row><entry namest="col1" nameend="col1" align="left">sample 4</entry><entry namest="col2" nameend="col2" align="center">400</entry><entry namest="col3" nameend="col3" align="left">rotgold</entry><entry namest="col4" nameend="col4" align="char" char=",">3.6</entry><entry namest="col5" nameend="col5" align="char" char=",">0.2</entry><entry namest="col6" nameend="col6" align="char" char=",">21.3</entry></row></tbody></tgroup></table></tables>

p0089In the application in varnish, the pigment flakes of all samples oriented by the action of a magnetic field in the still wet paint film along the field lines. In dried paint resulted in this way three-dimensional structures.