DE2057143A1 - Jewelry - Google Patents

Description

E-. I. DU POWT DE NEMOURS AND COMPANY 10th and Market Streets, Wilmington, Delaware 19 898, V.St.A,

Jewelry

The invention "relates to jewelry that is 20 to 100 percent by volume of heat-resistant nitrides, 0 to 70 percent by volume of heat-resistant oxides, borides or carbides and consist of 0 to 50 percent by volume of metal.

Some similar materials that have good hardness and strength, are described in U.S. Patents 3,409,416, 3,409,417, 3,409,418, and 3,409,419. It has now been found that the substances according to the invention when they become jewelry are deformed, have unusually advantageous properties. Refractory carbides are already in the making has been used by watch cases, as described in the United States patent 3 242 664 is described. Refractory carbides, however, have some disadvantages for making jewelry. Most heat-resistant carbides have moderate electrical conductivity, limited resistance against the corrosion by acids, as it is caused e.g. by Sohweiss, and a very high diet, ao that the out

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: * ^T \ n manufactured jewelry is quite heavy. It has now been found that decisive advantages are achieved if considerable amounts of special nitrides are added to the materials for such jewelry. Due to the presence of a nitride of titanium, zirconium, hafnium, niobium or vanadium, the acid corrosion resistance is increased and the density is reduced, so that the jewelry made from such materials is resistant to corrosion by perspiration and is specifically light. The nitrides also give the jewelry a distinct and unusual golden color that looks quite pleasing. Furthermore, the products according to the invention are unusually scratch-resistant. They can therefore be worn for a long time without getting scratched or tarnishing. The products according to the invention are also very strong and tough and therefore very durable compared to many natural and artificial stones and precious stones that are used for jewelry. Finally, the products according to the invention are quite heat-resistant and therefore do not melt or decompose at the temperatures at which the conventional metals or alloys melt.

The invention relates to jewelry made of a hard, polished mass, 20 to 100 percent by volume of a nitride of titanium, zirconium, hafnium, niobium, vanadium or mixtures thereof, to 0 to 70 percent by volume from a boride or Carbide of titanium, zirconium, niobium, tantalum, tungsten, molybdenum, hafnium, vanadium or chromium, aluminum nitride, aluminum oxide, Zirconium oxide, silicon dioxide, titanium dioxide, magnesium oxide, magnesium aluminate, oxides of the rare earth metals or mixtures these substances and 0 to 50 percent by volume of chromium, molybdenum, tungsten, iron, cobalt, nickel, titanium, zirconium, Niobium, tantalum, hafnium or mixtures thereof, a density of less than 9 g / cm, a porosity of less than 5 $, an average grain size of less than 10 μ, a ver

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ratio of Liditreflexionszeugens at 555 τημ to that at 450 κμ between 1.1: 1 and 1.6: 1 and resistance against corrosion by sweat.

Such jewelry is scratch resistant, strong, tough and very durable and have a pronounced golden color.

The products according to the invention consist of dense, fine-grained pests containing a heat-resistant nitride or a mixture of heat-resistant nitrides, namely nitrides of titanium, zirconium, hafnium, niobium and / or vanadium, in amounts of 20 to 100 percent by volume, an electrically non-conductive Component, namely silicon dioxide, titanium dioxide, magnesium oxide, aluminum nitride, aluminum oxide, zirconium oxide, magnesium aluminate and / or oxides of the rare earth metals, - in amounts of 0 to 70 percent by volume, an electrically conductive component, namely borides and / or carbides of titanium, zirconium, Niobium, tantalum, tungsten, vanadium, chromium., Molybdenum and / or hafnium, in amounts from 0 to 70 percent by volume, and chromium, molybdenum, ¹ % by volume, iron, cobalt, nickel, titanium, zirconium, niobium, tantalum and / or hafnium contained in amounts from 0 to 50 percent by volume. These pest substances are labeled

■ 2

due to a density of less than 9 g / cm, a low porosity, a small mean grain size, a polished surface resistant to acid corrosion such as that caused by human Sweat is caused, is resistant, and a light reflection compound at 555 ΐημ, which is 1.1 to 1.6 times as large iat v / ie the light reflection ratio at 450 ΐημ.

The products according to the invention are dense pesticides consisting essentially of heat-resistant nitrides TiN, ZrN, HfN, NbN, VN or mixtures thereof, optionally AlN, Al ₂ O ₃ , ZrO ₂ , Al ₂ O ₅ -MgQ, SiO ₂ , TiO ₂ , MgO, rare earth metal oxides or mixtures of these substances, optionally borides or carbides of Ti, Zr, Nb, Ta, W, Mo, V, Cr, Hf or mixtures thereof and optionally Cr, Mo, V /, Pe, Co, Ni , Ti,

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Zr, Nb, Ta, Hf or mixtures of these metals exist.

a) nitrides

The essential heat-resistant nitrides which are suitable for the purposes of the invention are titanium nitride, zirconium nitride, hafnium nitride, niobium nitride, vanadium nitride and mixtures thereof. These nitrides are used in amounts of 20 to 100 percent by volume. Since the corrosion resistance increases, the color becomes deeper and the specific gravity decreases as the content of nitrides increases, the nitrides are preferably used in amounts of at least 30 percent by volume, more preferably in amounts of at least 4-0 percent by volume and in particular in amounts of at least 50 percent by volume. Since it is expedient if at least some metal is present as a binder, the nitrides are preferably used in amounts of not more than 99 percent by volume, and in order to enable the presence not only of metal but also of other constituents, the content of nitrides is more preferably not more than 80 percent by volume and especially not more than 75 percent by volume. For this reason, it is also preferred that the products, if their nitride content exceeds 90 i <> , contain at least 1 ^c /> metal. Of the nitrides, titanium nitride is particularly preferred for the purposes of the invention, and the next preferred nitride is zirconium nitride.

The mean particle size of the nitrides should be less than 5 μ and preferably less than 2 μ. If the particles ■ of the starting material are significantly larger than 5 μ, the starting material can be pre-ground in order to reduce the particle size to an acceptable value. By grinding the various constituents of the preferred masses together in the mill, as is done in order to achieve a high degree of homogeneity, a certain degree of comminution of the nitrides and of the other starting materials is achieved.

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The nitrides to be used according to the invention can according to "any known processes, e.g. by nitriding the corresponding finely ground hydrides or Metals themselves according to US Pat. No. 3 4-09 416 or by reaction in a molten salt bath according to US Pat. No. 3,409,419 · The latter process is preferred because it contains nitride particles with an average particle size of less than 1 μ arise.

The nitrides can also be produced by reducing the corresponding metal oxides with carbon in the presence of nitrogen, as described in the literature. Known methods for producing the for the purposes of the invention essential nitrides are in Chapter VIII, entitled "Nitrides", of the work "High temperature Technology" by John M. Blocher jr., published by John Wiley & Sons, New York, 1956.

Typical commercially available nitrides suitable for the purposes of the invention are the TiN and ZrN powders with grain sizes below 44μ, available from Materials for Industry, Inc., Ambler, Pa., V.St.Α., as well as the TiN, ZrN and HfN powders with grain sizes below 44 μ and the NbN and VN powders with grain sizes below 149 μ »available from Consolidated Astronautics, Inc., Long Island City, New York, V.St.A.

b) Electrically non-conductive components

The electrically non-conductive components that can be used according to the invention are aluminum nitride, aluminum oxide, zirconium oxide, Silicon dioxide, titanium dioxide, magnesium oxide, magnesium aluminate (AIpO ^ MgO), the rare earth metal oxides and mixtures these substances. These ingredients are in 'amounts of 0 to 70 percent by volume applied. Preferred amounts of these constituents are 0 to 50 percent by volume, in particular 0 up to 35 percent by volume, and aluminum nitride is preferably used or alumina.

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The average particle size of these constituents should generally be be less than about 5 μ and in particular less than about 2 μ. As indicated above, the preferred oxide is alumina, and the particle size thereof is preferably less than. 2 μ, in particular less than 0.5 μ.

If the particles of the starting material are significantly larger than 5 μ, they can be pre-ground to reduce them to an acceptable Great to shred. When all components are married together, how it is done to a high degree of homogeneity: To achieve this, of course, there is also a certain comminution of the constituents.

The electrically non-conductive constituents suitable for the purposes of the invention can be in any desired form, provided that they are only finely divided. So the aluminum oxide ζ.Β. be in the form of γ-, Vfc- or α-alumina or mixtures thereof, α-alumina is preferred because it has a lower specific surface area than γ- or γ-alumina and generally also contains less adsorbed water.

These oxides can be prepared by known processes or can be obtained commercially. A suitable commercial alumina is "Alcoa Superground Alumina XA-16" with a

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specific surface of about 13 m / g. Suitable commercially available Forms of other oxides are in the form of powders using

Grain sizes below 44μ available from Materials for Industry, Inc.

The aluminum nitride can be produced by the same processes necessary for the production of the essential nitrides

de have been described. A suitable, commercially available aluminum nitride is one from Materials for Industry, Inc. obtainable powder with grain sizes below 44μ.

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c) carbides and borides

The electrically conductive borides and carbides according to the invention can be used are the carbides and borides of • titanium, tungsten, molybdenum, tantalum, zirconium, vanadium, chromium, Hafnium, niobium and mixtures thereof. These carbides and borides can be used in the materials according to the invention in Men --- Gen from 0 to 70 percent by volume. Preferred levels on these compounds are 0 to 45 percent by volume. The carbides of titanium, zirconium or tantalum or titanium diboride are preferably used, and this is particularly preferred Titanium carbide. ■

The carbides and borides suitable for the purposes of the invention should have an average particle size of less than 5 μ and preferably have less than 2 μ. If the starting material has particle sizes of significantly more than 5 μ, it can be pre-ground to reduce the particle size to 5 μ or less. When all components are married together As mentioned above, there is also a certain amount of comminution.

Suitable carbides and borides can be prepared according to known methods manufactured or obtained commercially. Typical suitable commercially available carbides and borides can be used as powders with grain sizes below 44 μ from Materials for Industry, Inc. or from Pirma Cerao Inc.

d) metals

The metals which can be used in the materials according to the invention are molybdenum, tungsten, chromium, iron, nickel, cobalt, titanium, zirconium, niobium, tantalum, hafnium and mixtures thereof.

These metals are in the materials according to the invention in Contains quantities from 0 to 50 percent by volume. Preferably included the materials at least 1 percent by volume, in stronger preferably at least 5 percent by volume and preferably

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not more than 20 percent by volume, in particular not more than 15 percent by volume metal, because in this area an optimum the chipping resistance when cutting and grinding the Pieces as well as the ease of polishing and corrosion resistance occurs.

Of the heat-resistant metals, molybdenum is preferred or tungsten or mixtures thereof with ferrous metals are used. Of the iron metals, nickel is preferred. Particularly the joint use of molybdenum or tungsten with nickel is preferred.

As already mentioned, the materials according to the invention have relatively high metal contents, namely up to 50 volume percent metal. An increase in the metal content however, should go hand in hand with a corresponding increase in the boride, carbide or oxide content in order to ensure corrosion resistance of the materials. It is believed that molybdenum is in the lattice of carbides, such as titanium carbide, diffused into it, so that little or no free metallic molybdenum remains, if enough Carbide is present, whereby the high corrosion resistance is maintained.

The metals suitable for the purposes of the invention should have mean particle sizes of less than 5 μ and preferably of less than 2μ. If the starting powder has particle sizes of significantly more than 5 μ, it can be pre-ground to reduce the particles to 5 μ or less «when all components are ground together of course, as already mentioned, some crushing also takes place.

Metal powder of the required grain size and the required Degrees of purity are commercially available or can be made in a known manner. A suitable manufacturer

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The solution method is the reduction of the corresponding metal oxides with hydrogen at low temperatures or reduction of iron, cobalt or nickel carbonate with hydrogen Temperatures of about 600 to 1200 ° 0. Such manufacturing processes should be carried out at the lowest possible temperatures in order to sinter and agglomerate the metal to suppress if possible.

In the manufacture of molybdenum and tungsten from their oxides it is best to use a two-stage reduction because some of these oxides are relatively volatile » The first reduction stage is below the melting point of the oxide, e.g. at 600 ° C. Then it closes the second reduction stage at 900 C, for example which the reduction will be completed.

The metals produced by the methods described above can be ground in an inert medium to their specific To enlarge the surface, and then they can be cleaned with e.g. hydrochloric acid »For grinding the metal it is preferable to use grinding media made of the same metal, that is to be ground, or from the components that are to be mixed with the metal, or from a very wear-resistant one Substance so as not to introduce impurities through abrasion of the grinding media.

Typical suitable and commercially available metals are fine Woifram powder from General Electric, Detroit, Michigan, V.St.A., with a specific surface area of 2 m / g as determined by nitrogen ado option, as well as fine nickel powder available from International Nickel Co. a given nitrogen adsorption specific surface ¹ -flat of 0.5 m / g ·

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e) Preference e η

Those used to manufacture the materials according to the invention Components should preferably be very pure. It is particularly desirable to remove impurities such as oxygen, that can adversely affect the dense hates.

On the other hand, ■ small amounts of many impurities that do not significantly "impair the properties of the products" are permitted. "For example, the metal may contain small amounts of other metals; however, it should not contain any low-melting metals such as lead. Other carbides may be present. Even small amounts of oxygen, such as those contained in titanium carbide, in which a few percent of titanium oxycarbide have formed due to the action of air. Once the powdery components have been ground together, however, may be permitted and are in an extremely reactive state, oxidation, especially of metals, easily takes place and should be avoided.

The preparation of intimate mixtures of the nitrides with the borides, carbides, oxides or metals, if any, are added in the form of a powder Patent US 3,409,416 can be carried out according to the.

The intimate powder mixtures of carbides and oxides and optionally The metal are processed into a dense solid material by sintering or hot pressing, as in the U.S. Patents 5,409,416 and 3,415,392 and U.S. Patent Application Serial No. 846 525 of July 31, 1969.

The dense masses - which essentially consist of nitrides and optionally containing oxides, carbides, borides and metals, can without the use of any other substances

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be deformed into jewelry. The dense masses can do better Also attached to a base made of metal, wood, plastic or textile "or as a setting for precious stones, Semi-precious stones or minerals are used. The so obtained Jewelery can be used for ceremonial purposes or serve both purposes at the same time.

Jewelery is so well known and its sizes, shapes, combinations of components and uses are so diverse that that it is impossible and unnecessary to enumerate all kinds of jewelry for which the masses believed in the invention Can be used · The following abbreviated list is just a few examples of suitable applications give. The materials according to the invention can stand alone or together with any structural fabrics or Clothing fabrics, such as metal, wood, glass, minerals, plastics, ohioh, paper, leather, precious stones, shells or synthetic organic or inorganic substances. Combinations can, for example, by brazing, soldering, gluing, Putty, edging, dowelling and sewing are made. In this way, jewelry can be like make the following:

Watch cases, hinge, cufflinks, tie pins, earrings, Collars, needles, buttons, clips, decorative hangers, snap buttons, cigarette cases, bracelets, metal decorations, Monograms, victory trophies, medals, piace openers, shoehorns, hairpins, hair accessories, shoe buckles, belt buckles, Pill boxes, powder compacts, buttons for clothes or skirts, talismans for bracelets, identification badges, Badge, paperweight.

Process for making such jewelry and for cutting and deforming the diohten masses according to the invention and to polish, are known to the person skilled in the art and in detail described in the following examples.

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The materials according to the invention are characterized by their reflection ratio for different wavelengths of the visible light, their corrosion resistance to the action of sweat, their high mechanical strength, their exceptional toughness and hardness, density, low porosity, small grain size and homogeneity of the mutual mixing of the components.

The mechanical strength and hardness are determined according to the known methods for determining the transverse breaking strength and the Rockwell A hardness.

Methods for determining the porosity, the grain size and the homogeneous nature of solid substances are described in US Pat. No. 3 4-09 * 416. The compositions according to the invention are characterized by a porosity of less than 5 ° and an average grain size "Of-less than 10 μ. The compositions according to the invention preferably have a porosity of less than 1 $ and an average grain size of less than 2 μ.

The toughness is only determined qualitatively by placing the finished product freely on a hardwood floor from a height of 2.13 m drops. The products according to the invention do not break or split off.

The actual density of the masses according to the invention can be determined P by known methods, the simplest being by a previously measured sample is weighed in air and under water. The water should be boiled before weighing the sample to expel dissolved air. The density is then calculated from the equation

Weight in air χ specific weight

Density = ^{of water}

Weight in air - weight in water

The theoretical density of the masses can be calculated on the basis of the

can be calculated that the volume of a given area

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weight amount of the mass equal to the sum of the volumes of the components which in turn is calculated from the weight of the individual components divided by their density will *

The solids according to the invention have a density of less than 9 g / cm, and since their porosity is generally less than 1 fo , their actual density is usually higher than 99 # of their theoretical density.

One of the characteristic properties that fabrics have so3.1en, so that they are suitable for jewelry that is worn in constant contact with the skin, such as rings, Bracelets and watch cases, is their corrosion resistance to the secretions of human skin. It is * e.g. known that even stainless steel watch cases completely corrode on the arm of normal wearers in hot climates can-. To assess this property, one makes a corrosion test in a "liquid of the middle" Composition of human sweat use. A solution is prepared, the composition of which is based on the information in the work "Normal Values in Clinical Medicine" by F.W. Sunderman and F. Boerner (Verlag W-.B. Saunders Co., Philadelphia and London, 1949) on page 488 corresponds to the mean composition of human sweat. the The composition is as follows

Water '99.02

Sodium chloride 0.7

Lactic acid Ο ', 1

Acetic acid 0.00 ^ 6

Propionic acid 0.0062

Caprylic acid and caproic acid 0.0046

Citric acid. 0.004

Ascorbic acid 0.004

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Urea 'or uric acid, the' as 'traces' in the middle Composition of human sweat are given, are not added to the corrosion test solution. The corrosion test solution is placed in a beaker at a constant bath temperature of 40 ° C and with the help of glass stirrers mildly touched.

The cuts used for the corrosion samples have a size of 20.57 mm χ 12.7 mm x 2.54 mm. You will be like 3These can be cut with resin bonded diamond cutting wheels without further grinding or polishing for the test is used, with the exception of a possible adaptation of the cuts to the standard size.

The neat test samples are accurately weighed and measured and then immersed in boiling dimethylformamide for 4 minutes to remove the . To remove impurities from the surface. After the out + take from the dimethylformamide, the sections are washed with water and acetone, dried in a vacuum oven and immediately transferred to the corrosion test solution.

Samples are taken from the corrosion test liquid at measured time intervals removed, rinsed with distilled water and acetone, dried in a vacuum oven and then weighed again. Then they are cleaned again in boiling dimethylformamide, rinsed with water and acetone, dried and fc again placed in the corrosion test liquid. The weight loss per unit of surface area of the sample is calculated for calculated the given time periods. The surfaces of some samples are checked before the start of the test and at certain time intervals examined by optical photomicrograph during the test to observe the extent of the etch.

The dense masses according to the invention are characterized duroh a weight loss of less than 5 mg / cm after 10 days of immersion in the synthetic

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»!» ■ "'Ni .;. _: ^ T ■■ ιι ■;: | _.: | Ι ■! _L; | lιH.ι.; || l _Π l |:! ||| _fl ll ||| l |! ||| ₁ ιι _: |, ,,. ■. "■;, ■■ _Τ ιρ ,, || ρ _;;

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see white solution "at 4-0 ° C. This corrosion resistance ' against perspiration is higher than that of 'tungsten carbide bound with cobalt, -which is currently used in the manufacture of 'scratch-resistant watch' case is used.

The attractive appearance of the materials according to the invention is one of the most important properties to use for Jewelry,

The materials according to the invention have a golden appearance due to the lack of blue wavelengths in the reflected spectrum of visible light (about 400 to 700 ΐημ). C The golden color of the masses according to the invention ranges from golden yellow to golden bronze. The color of these masses is identified by determining the ratio of their light reflectivity at 555 ΐπμ to that at 450 ΐπμ. To the extent that the yellow or gold-colored component in the composition of matter increases, so does the ratio IR / IE., _{_ O.} IRccc. is the percentage intensity of the reflected light with a wavelength of 555 ιημ, and IR450 ^ ^{s <t is} the percentage intensity of the reflected light with a wavelength of 450 ΐημ. ;

The determination of the light reflectivity of the materials According to the invention, it is expedient to use the following Method:

A Bausch & Lomb spectrophotometer (Spectronic 505) with a . Integrating sphere accessory.

The spectrum registered with the spectrophotometer is through Directed illuminating radiation and diffuse viewing from the integrating sphere with a trap for the reflective one Get reflection.

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In ^Palle: diffuse reflection, the integrating sphere collects all diffusely reflected light (not the direct specular reflection) from the surface of the sample · disposed at an opening in the side of the ball ·. The integration sphere is a hollow metal sphere with a multiple of 2.5 cm in diameter, which is painted white on the inside. The illumination of the sample is set at an angle to the vertical line in such a way that the specularly reflected light is captured in a light trap and therefore does not contribute to the spectrophotometer reading.

The samples for the determination of the light reflectivity consist of circular samples with a diameter of 38.1 mm and from rectangular specimens 38.1 mm 30.16 mm, which are hot-pressed, have a flat surface and are arranged on Bakelite supports of * 50.8 mm in diameter, which cursing with the samples. This sample size is large enough to ensure that the surface is in the area of the light beam of the device is located, and that the samples fit tightly enough into the opening to prevent light losses impede.

The surface of the sample is flat, ground and polished. Polishing is done first with the help of resin-bonded Diamond grinding discs Ur. 400 and no. 1000 ("Vespel") of 20 cm in diameter, "which runs at speeds of 1175 resp. 550 rpm, revolve. The surface is post-treated by polishing with diamond paste (grain size 6 μ) under Use of luminous oil as a lubricant and with the help of a rotating, soaked with diamond dust (grain size 1 μ) Cloth disc using water as a lubricant.

Bs is important that all measurements are performed on samples that have been polished under normal conditions, since the degree of optical smoothness of a surface determines the extent to which incident light in all directions re-

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is inflected. A diffuse light reflective surface tends to be to reflect evenly in all directions. Rough or porous surfaces therefore reflect in all directions. The smoother the surface, the more directed is the reflection.

The measurements obtained with the device ■ give the percentage light transmission as a function of the wavelength. The masses according to the invention are characterized by smooth Light reflection curves without maxima, but with "an increasing reflectivity from the blue area of the visible Spectrum, and by a ratio of the percentage reflection at 555 ΐπμ to that at 450 ιιιμ between 1.1: 1 and 1.6: 1.

The jewelry according to the invention can be used purely for ornamental purposes Or used for both practical and decorative purposes at the same time. These jewelry materials have an unusually pleasing metallic sheen, which due to the presence of the nitrides has an unusual golden tone having. Although the unusual appearance is due to the presence of the nitride phase, the difference can be seen in the Appearance, as with most aesthetically pleasing effects, can be observed with the human eye, but is difficult to define or measure quantitatively. In contrast to the conventional metals, such as stainless steel, silver or gold, are those consisting of the materials according to the invention. Jewelry unusually scratch-resistant. As a result of their embarrassment and their lack of porosity, the materials can be polished to an unusually high degree, and the A surface polished in this way becomes inclusive even with rough treatment with conventional building materials or clothing Metal, glass, concrete, bricks, wood, plastics, etc., not scratched or matt. Considering their good corrosion resistance the jewelry according to the invention can be in contact with human skin and with

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Sweat-worn without seriously tarnishing. The crowds according to the invention are stronger and tougher than many. • Materials, such as natural or man-made stones, or gemstones or jewel mounts, and therefore they are more durable. Since the substances according to the invention are extremely heat-resistant, they suffer at high temperatures at which conventional ones Metals or alloys break down, no melting and no decomposition. This unusual combination of properties makes the fabrics surprisingly valuable for use in jewelry.

In the following examples, parts and percentages are based on weight, unless otherwise specified.

example 1

The mass of this example contains 50 percent by volume titanium nitride, 20 percent by volume aluminum oxide, 15 percent by volume aluminum nitride, .12 percent by volume tungsten and 3 percent by volume nickel.

The titanium nitride has grain sizes below 44 μ and one through Specific surface area of nitrogen adsorption

1 »1 m / g« A picture of the powder taken with an electron microscope shows dense particles of irregular shape with sizes between 1 and about 10 μ, the majority of which have particle sizes between 1 and 2 μ. The | The carbon content is 0.33 #, the oxygen content 0.87 ^. The chemical analysis gives 76.19 f * titanium and 18.71 $> nitrogen.

The aluminum oxide is a very finely divided α-aluminum oxide ("Alcoa Superground Alumina XA-16") and is identified by X-ray diffraction analysis as pure α-aluminum oxide. It has

a specific surface of 13 m / g, which corresponds to spherical particles with a size of 115 ΐημ. Under the Electron microscope, this a-aluminum oxide powder appears in the form of aggregates of alurainium oxide crystals with a diameter

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sern from Ί00 to 150 αμ.

The aluminum nitride is a powder with grain sizes below ' 44 μ and has a surface area determined by nitrogen adsorption of 2.3 m / g. A picture taken with an electron microscope shows dense, very irregular particles Shape. The spherical particles have diameters between 2 and 12 μ, and the elongated particles show one Width from 1 to 3 μ and a length between 4 and 16 μ. The carbon content is $ 0.43 »the oxygen content is $ 1.55. Chemical analysis shows that the powder is 63 »95 # aluminum and contains 32.27? 6 nitrogen.

The tungsten is a finely divided powder with a specific surface area of 2.0 m / g and an oxygen content of 0.19 ° ß> · The crystallite size, determined by broadening the X-ray diffraction lines, is 174 πιμ. *

The nickel is also a fine powder and contains 0.15 $ carbon, 0.07 ί> oxygen and less than 300 ppm iron.

The specific surface area of the nickel powder is 0.48 m / g, and its X-ray diffraction diagram shows only nickel, which, determined by the broadening of the X-ray diffraction lines, has a crystallite size of 150 μm. Under the electron microscope the powder seems to consist of grains with a diameter of 1 to 5 μ »

The powders are ground by using a 1.3 liter steel roller mill of 15 cm diameter with 6000 parts pretreated, cylindrical grinding media made of cobalt bound . Denem tungsten carbide 6.35 mm in length and 6.35 mm in diameter and with 290 parts of saturated paraffin hydrocarbons (boiling range 165 to 210 ° 0, "Soltrol 130"). 81.45 parts of titanium nitride and 14.66 parts of aluminum nitride are added to the mill feed , 23.88 parts of ot-aluminum oxide, "69.33 parts of Wolfraopowder and 9.08 parts of Niokel powder added". · ■

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The mill is then closed and rotated at 90 rpm for 5 days calmly. After opening the mill, the contents are discharged, but the grinding media remain in the mill. The mill is flushed with the paraffinic hydrocarbons noted above until all of the ground pests are discharged are.

The ground powder is transferred to a vacuum evaporator, and the excess hydrocarbons are poured off after the suspended matter has settled. The remaining one wet cake is dried in vacuum with the action of heat until the temperature of the evaporator between * 200 and 300 ° C, with the pressure less than 0.1 mm Hg. The powder is then only excluded handled by air

The dry powder is passed through a sieve using nitrogen 0.21 mm mesh size poured and then stored in sealed plastic containers under nitrogen.

A watch case is made from this powder by hot-pressing the powder in a graphite mold, which is built in such a way that the powder can be shaped into a ring with a round hole during hot-pressing, which is so large that the encapsulated clockwork has a The wristwatch can be inserted into the ring later ψ by a press fit, with the ring serving as a protective and decorative case. The graphite mold consists of a 10.16 cm long hollow graphite cylinder with an outside diameter of 6.35 cm, and the cross section of the cavity is in the shape of a square with rounded sides. The maximum clear width of the cylinder is 5.08 cm. A hollow piston is inserted into the lower end of the cylindrical mold, the outside diameter of which is dimensioned so that the piston fits exactly into the shape of the inside diameter of the mold. The piston has a cylindrical cavity of round cross-section with a diameter of 4.13 cm. That

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The end of the "piston" in the mold is beveled or shaped like a bowl, so that the bottom of the ring to be formed from the powder does not have a flat surface but a pleasing rounded surface. A third hollow cylinder with an outside diameter of 4.13 cm and a The wall thickness of 1.59 mm fits exactly into the hollow piston and protrudes beyond the piston into the mold. A solid rod fits into the thin-walled inner cylinder in such a way that: it prevents it from collapsing during the pressing process Thirty-two parts of powder, calculated to make a completely tightly compressed piece of the correct thickness, is poured into the mold and tapping the mold in the area of the inside wall of the mold, the outside surface of the thin-walled, cylindrical spacer and the The hollow space formed at the top hollowed out end of the bottom piston is then slumped in. Then a second hollow piston is inserted from above inserted the aggregate that forms the upper surface of the powder cavity. The entire unit is placed in a hot press, heated quickly to 1000 ° 0 and then over the course of 10 minutes to 1800 ° 0. The temperature is held at 1800 ° C. for 2 minutes, and then a pressure of 350 kg / cm is applied from above and below through massive graphite pressure pistons, which act on the ends of the hollow pistons protruding from the top and bottom of the mold . The pressure is held for 4 minutes, and then the supply of heat is interrupted and the pressure is released. The mold is then immediately removed from the hot zone and the solid rod serving as a spacer is allowed to slide out of the center of the unit. When the mold cools down, the pressed watch case ring contracts more than the graphite. If the solid rod were left in place, the ring would break as a result of the developing stresses. Instead, the shrinking ring presses the thin-walled graphite cylinder remaining in the hole together, and

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The cylinder, but not the ring, bursts. The thin-walled one The only task of the cylinder is to facilitate the initial pulling out of the solid rod, otherwise it will stick to it would be held on to the ring. When the mold has cooled, the pistons and the ring, if necessary, by pressure, removed.

The watch case is polished by pressing its surfaces firmly against rotating cloth disks soaked with diamond dust. A machine from Buehler, Ltd. is used to polish the sample. used. In the first stage of polishing a diamond grinding bills number is. Ten with a rotational speed of 1175 rev / min, and in the two-P 400, the last process step of grinding a · diamond disc no. 1000 with a speed of 550 rev / min, is used.

The finished watch case has a pleasing golden color.

Example 2

You work according to Example 1, but without the addition of aluminum oxide, The remaining ingredients are used in proportions such that the powder mixture increases 50 percent by volume of titanium nitride, 30 percent by volume of aluminum nitride, 18 percent by volume of tungsten and 2 percent by volume percent is nickel.

Accordingly, the 1.3 1 steel mill with 81.5 parts, titanium nitride, 29.3 parts AlN, 104 parts tungsten and 5.4 parts of nickel charged.

A compacted ingot is made from the powder by using the powder in a cylindrical graphite shape a cavity of. square cross-section of 27 mm 27 mm, with exactly fitting pistons facing each other is equipped, hot-pressed. A piston is in one end

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of the mold cavity held in place, 40 parts of powder being poured into the cavity under nitrogen and distributed evenly by turning the mold and tapping lightly on one side. Then the upper piston is inserted in place under pressure by hand. The assembled form with its contents is then placed in the vacuum chamber of a vacuum hot press, the press is held in a vertical position, and the pistons protruding upwards and downwards are pressed together between the two opposite graphite pistons of the press under a pressure of 42 kg / cm. Within a minute, the mold is lifted into the hot zone of the oven, which is ¹ to 1175 ° 0, and the oven temperature is increased immediately, with the two plungers locked in their positions so that no further movement can take place during the heating period. The temperature is increased from 1175 to 1800 ° 0 within 10 minutes and held at 1800 0 for a further 2 minutes in order to ensure uniform heating of the sample. A pressure of 280 kg / cm is then applied via the flasks for 4 minutes. Immediately after pre-pressing, the mold and its contents, still between the opposing plungers, are taken out of the oven into a cool zone, where they cool down to a dark red glow within 5 minutes. , ·

Then the mold and its contents are removed from the yakuum oven and the ingot removed from the mold and freed from adhering carbon with the sandblasting blower.

The density of the finished product, determined by accurate weighing and determining the dimensions, is 7.25 g / cm.

The hot-pressed mass is non-porous by being at 1000 'fold Magnification shows no visible porosity. This property is important because non-porous materials are more resistant to corrosion are as porous substances of the same chemical composition.

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Structurally "the mass consists of an extremely fine, coherent network of interpenetrating Titanium nitride; Aluminum nitride and metal alloy.

The sample is so tough that it does not "break or split off, if you place them freely on a hardwood floor from a height of 2.13 m drops.

Images made with the electron microscope show a very fine-grain structure, with a few grains larger than 1 or 2 μ.

The sample is polished by pressing its surfaces firmly against rotating cloth disks impregnated with diamond dust. A Buehler polishing machine is used for this »A Diamond grinding wheel No. 400 with a rotational speed of 1175 rpm, is used in the first process stage of polishing and a diamond grinding wheel No. 1000 with a rotational speed from 550 rpm, in the second and last Polishing process stage used.

The sample polished in this way has a pleasing appearance and a golden color.

The polished sample is used for color measurement with the aid of the Bausch and Lomb spectrophotometer (Spectronic 505). By * diffuse reflection · with the integrating sphere one obtains a Curve relating to an 8 percent light transmission on the irradiated wavelength.

• The curve for the reflectivity increases gradually from a flat part at about 9.2 ^ light reflection at the violet end of the spectrum between 400 and 435 ΐΐιμ to about 15.5 ° light reflection at the red end of the visible spectrum. This lack of blue wavelengths in reflected light gives the material its decidedly golden appearance. The reflectivity is $ 9.3 at 450 ΐημ

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and "at 555 ιημ $ 12.3, which corresponds to a ratio of 1.3: 1.

As a result of the low light reflection even in yellow to red Part of the spectrum sees the material much darker than metallic Gold turns out to be a tie pin.

Example 3

Example 1 is used, but with one composition 50 percent by volume titanium nitride, 30 percent by volume aluminum oxide, 5 percent by volume aluminum nitride, 12 percent by volume tungsten and 3 volume percent nickel.

Accordingly, a steel mill with a capacity of 3.785 l is charged with 299 parts of TiN, 131.5 parts of Al ₃ O ₅ , 18 parts of AlN, 255 parts of W, 29.4 parts of Ni and 1040 parts of paraffinic hydrocarbons ("Soltrol 130").

A square bar produced according to Example 2 with side lengths of 27 mm and a thickness of 0.76 mm is thus cut up so that samples of 20.3 mm 12.7 mm 2.54 mm are obtained from its central part. ■.

These samples are used as sections during the corrosion test in the liquid described above on the composition of the human sweat used. The tests are carried out at a constant temperature of 40 ° C.

The test is carried out by looking at the samples for a specific Leave time in the corrosion test liquid, then take out, wash with water and acetone, in the vacuum oven dries and weighs again. After weighing, the samples are cleaned in boiling dimethylformamide with water and acetone and, when dry, returned to the corrosion test bath. This procedure is used for

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repeated for different periods of time.

The corrosion test liquid is used during the investigation gently stirred, and its temperature is in a thermostatic bath held at 40 ° G.

After 10 days, "the mean weight loss of the sample is" be

only 1.8 mg / cm. Under the same test conditions, shows what is commercially available Tungsten Carbide ("Garboloy 90") one

mean weight loss of 25 mg / cm.

Examination of the tungsten carbide sample under the optical microscope at 740 magnifications after 10 hours longer The action of the corrosive liquid under the conditions described above shows that the surface is largely etched is. The composition according to the invention, on the other hand, shows after 10 hours of exposure to the corrosive liquid under the optical microscope only a slight etching of the surface.

A rectangular piece of 12.7 mm 3.18 mm is cut from the bar, polished and given a more pleasing, golden appearance Decorative insert used by cementing it to a tie clip with an epoxy resin.

Example 4

Example 1 is used, but with a powder composition of 50 percent by volume zirconium nitride, 30 percent by volume aluminum nitride, 18 percent by volume molybdenum and 2 percent by volume Nickel.

The zirconium nitride powder used here is a commercially available one Powder (Materials for Industry, Inc., Ambler, Pa., V.St.A.) has a purity of 99.9 # and a particle size from 0.5 to 5 μ.

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The aluminum nitride powder and the nickel are the powders described in Example 1.

The molybdenum powder (from General Electric Co.) has a grain size of less than 44 μ »a specific surface area of 0.29 m / g determined by nitrogen adsorption and an average crystallite size of 354 μm determined by line broadening in X-ray diffraction. A picture taken with an electron microscope shows that the molybdenum powder consists of grains 1/2 to 3 μ in diameter that adhere to one another in the form of open aggregates. Chemical analysis of the powder shows $ 0.2> oxygen and no other impurities in amounts greater than 500 ppm.

The 1.3 liter mill is charged with 106.35 parts of ZrN, 29.35 parts of AlN, 55.07 parts of Mo and 5.39 parts of Ni. ',

A watch case made from this mass according to Example 1 has a pleasing golden appearance and breaks does not splinter or splinter if it falls from a height of 2.13 m onto a hardwood floor.

Example 5

The procedure is as in Example 1, but with a powder of the following Composition: 63 volume percent titanium nitride, 30 volume percent aluminum oxide, 4 volume percent tungsten and -3 volume percent Nickel.

The 1.3 1 steel mill is accordingly with

J TiN, 35, S2 parts Al ₂ O ₅ , 23.15 parts Yl and 8 parts Ni charged.

An ingot produced from this powder by hot pressing according to Example 2 has a density of 6.15 g / ovP, a Rockwell A hardness of 92.2 and a transverse breaking strength of

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102.6 kg / mm. The bar is very tough and does not break or shatter from it-if from a height of 2.13 m falls on a Harth'olzfussboden.

The ingot is cut so that from the middle. a rectangular piece 14.3 mm by 4.76 mm on a side is removed. The rectangular piece is polished by pressing its surfaces firmly against rotating cloth discs impregnated with diamond powder. A polishing machine from Buehler, Ltd. is used for this purpose. used. A diamond grinding wheel No. ₁ . 400 at a speed of 1175 rpm, is the first step in polishing and a diamond grinding wheel ITr. 1000 with a rotational speed of 550 rpm, used for the second process stage of polishing.

The rectangular piece thus polished has a shiny, golden appearance and is used as an ornamental insert by using it with Epoxy resin is cemented to the surface of a metal tie clip.

Example 6

Example 1 is used, but with a powder composition made of 50 percent by volume titanium nitride, 20 percent by volume aluminum nitride and 30 percent by volume tungsten.

Accordingly, the 1.3 liter steel mill is charged with 81.4.4 parts of TiN, 19.55 parts of AlN and 174.00 parts of W.

An ingot produced according to example 2 with the difference that the maximum temperature used during hot pressing 1850 ° 0, has a density of 9.16 g / cm and a transverse breaking strength of 112.5 kg / mm. The bar is very tough and can fall on a hardwood floor from a height of 2.13 m dropped without breaking or chipping.

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The bar from this composition is made according to the example. 5 cut and polished to give a 12.7 mm square piece of metallic gold Appearance. The square piece is used as a decorative insert by cementing it to a medallion with epoxy resin will.

Example 7

You work according to Example 1, but with a powder composition 50 percent by volume titanium nitride, 45 percent by volume titanium diboride, 4 »5 percent by volume molybdenum and 0.5 percent by volume Nickel.

Accordingly, the 1.3 1 steel mill is charged with 83 parts of IiIT, 62 parts of TiB ₂ , 4.5 parts of Mo and 1.3 parts of Hi.

The titanium diboride powder (from Mrma Materials for Industry, Inc.) has a specificity determined by nitrogen adsorption Surface area of 1.1 m / g and an oxygen content of 2.32 #.

An ingot produced according to Example 1 has a density of 5 g / cm, a Rockwell Α hardness of 92.7 and a transverse breaking strength of 80.85 kg / mm.

The ingot is cut with a diamond wheel bonded with resin, and after polishing you get two shiny gold ornaments. -The pieces are epoxy on two metal ones Cufflinks cemented on.

Example 8

Example 1 is used, but with a powder composition of 85 percent by volume of carbon nitride, 12 percent by volume of chromium and 3 percent by volume of iron.

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The niobium nitride powder (from Cerac, Inc., Butler, Wisconsin, V.St.A.) has grain sizes below 44 μ and a Purity of 99.5 5 ^ ·

The chromium powder (from Materials for Industry, Inc.) has a purity of $ 99.9 and particle sizes of 1 to 3 5 μ, determined with the Fisher sub-sieve size classifier. The specific surface area determined by nitrogen adsorption is 0.8 m / g and the oxygen content 0.79 / »· one Electron microscope image of this powder shows dense particles, most of which have smooth edges and have only a few scalloped edges; the particle sizes are between 1 and 4 μ. Most of the particles P have a size of about 2 μ.

The ferrous metal powder (from Materials for Industry, Inc.) has particle sizes between 1 and 5 microns and a purity of 99.9% .

The 1.3 l steel mill is charged with 214.17 parts of NbN, 24.77 parts of Or and 7.06 parts of Fe.

An ingot produced according to Example 2 has a density of 8.23 g / cm ³ .

The bar is cut up and polished according to Example 5, _fc, and a rectangular piece with a side length of 12.7 mm × 3.18 mm and a golden appearance is obtained. The rectangular piece is used as a decorative insert by cementing it onto a tie clip with epoxy resin.

Example 9

You work according to Example 1, but with a powder composition from 70 percent by volume titanium nitride, 27 percent by volume

Tungsten and 3 percent by volume nickel.

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The 1.5 1 'steel ratio is made with 118.3 parts of TiN, 162 parts of W and 8.32 parts of Ni were charged.

According to Example 1, a watch case becomes more attractive made of golden color.

Example 10

Example 1 is used with a powder mixture of 50 percent by volume titanium nitride, 45 percent by volume tantalum carbide, 4.5 percent by volume tungsten and 0.5 percent by volume nickel.

The tantalum carbide powder (from Adamas öompany) has a medium size Particle size of 3μ, one by nitrogen adsorption certain specific surface area of 0.38 m / g and one Oxygen content of 0.07 ^.

The 1.3 1 steel mill has 81.46 parts. TiN, 197.76 parts TaC, 25.60 parts W and 13.03 parts Ni.

A watch case made from the material according to Example 1 shows a gold color.

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Claims (1)

2057H3 EGG. du Pont de Nemours November 20th 1970 and Company 4249-G Claims 1- »Jewelery made from a hard, polished mass, characterized that the mass to 20 to 100 percent by volume "of an essential nitride, namely a nitride of Titanium, zirconium, hafnium, niobium, vanadium or mixtures of such nitrides, from 0 to 70 percent by volume from a boride or carbide of titanium, zirconium, niobium, hafnium, tantalum, tungsten, vanadium, chromium, molybdenum or mixtures thereof Borides and carbides, from 0 to 70 percent by volume of an electrically non-conductive component, namely aluminum nitride, Aluminum oxide, titanium dioxide, zirconium oxide, silicon dioxide, magnesium oxide, magnesium aluminate, oxides of the rare earth metals or mixtures of these compounds and 0 to 50 percent by volume of chromium, molybdenum, tungsten, Iron, cobalt, nickel, titanium, zirconium, niobium, tantalum, haf- There is a 'density' of less than 9 g / cm, a porosity of less than 5 "/, an average grain size of less than 10 μ, resistance to corrosion caused by sweat and a ratio of light reflectivity 555 ΐπμ to that at 450 ΐημ between 1.1: 1 and 1.6: 1. 2. Jewelry according to claim 1, characterized in that the mass has a porosity of less than $ 1 and a medium -32-109822 / 0044 ₃₅ '2057U3 4249-G ler grain size of less than 2 μ. 3, jewelry "according to claim 1, characterized in that the proportion of the 'essential nitrides 30 "to 99 percent by volume and the metal content is 1 to 50 volume percent. 4. Jewelry according to claim 1, characterized in that • The mass consists of 40 to 80 percent by volume of the essential nitrides, 0 to 70 percent by volume of borides and / or. Carbides, from 0 to 50 percent by volume from the electrically non-conductive component and from 1 to 20 percent by volume made of metal. 5 · jewelry according to claim 1, characterized in that the ratio of the light reflectivity at 555 πιμ to that at · 450 πιμ is between 1.15: 1 and 1.5: 1. 6. Jewelery according to claim 5, characterized in that the mass consists of 50 to 75 percent by volume of titanium nitride and / or zirconium nitride, from 0 to 35 volume percent from aluminum nitride and / or aluminum oxide, from 0 to 45 volume percent from titanium diboride, titanium carbide, tantalum carbide and / or zirconium carbide and from 5 to 15 percent by volume Molybdenum, tungsten or mixtures of these metals with iron, cobalt or nickel. 7. jewelry according to claim 6, characterized in that the mass as essential nitride titanium nitride, as boride or carbide titanium carbide and as metal molybdenum, volfram or mixtures of these metals with nickel. 8. watch case with an exposed exterior made of a hard, polished mass, characterized in that the 20 to 100 percent by volume of a substantial nitride, namely a nitride of titanium, zirconium, hafnium, , .Niobium and / or vanadium, from 0 to 70 percent by volume from one Boride or carbide of titanium, zirconium, niobium, hafnium, · Tanr - 33 1098 2 2 / '0 0U 2057U3- 4249-G ^ tal, tungsten, vanadium, chromium and / or molybdenum, from 0 to 70 percent by volume of an electrically non-conductive component, namely aluminum nitride, aluminum oxide, titanium dioxide, zirconium oxide, silicon dioxide, magnesium oxide, magnesium aluminate and / or oxides of the rare earth metals and from 0 to 50 percent by volume consists of chromium, molybdenum, tungsten, iron, cobalt, nickel, titanium, zirconium, mob, tantalum and / or hafnium, a density of less than 9 g / cm, a porosity of less than 5 ° / °, an average grain size of Less than 10 μ, resistance to corrosion caused by sweat and a ratio of the light reflection capacity at 555 ΐημ to that at 450 ΐημ between 1.1: 1 and 1.6: 1. ^ 9 · Watch case according to claim 8, characterized in that the mass has a porosity less than $ 1 and a has an average grain size of less than 2 μ. 10. Watch case according to claim 8, characterized in that the proportion of the essential nitrides is 30 to 99 percent by volume ■ and the metal content is 1 to 50 percent by volume. 11. Watch case according to claim 8, characterized in that the mass consists of 40 to 80 percent by volume of essential nitrides, 0 to 70 percent by volume of borides and / or carbides, 0 to 50 percent by volume of the electrically non-conductive component and 1 to 20 percent by volume of metal ™ tall consists. 12. Watch case according to claim 8, characterized in that the ratio of the light reflectivity at 555 τημ to that at 450 ιημ is between 1.15: 1 and 1.5: 1. 13. Watch case according to claim 12, characterized in that that the mass is 50 to 75 percent by volume of titanium nitride and / or zirconium nitride, from 0 to 35 percent by volume Aluminum nitride and / or aluminum oxide, from 0 to 45 volume - 34 -109822/0044 2057 H.3 4249-G. Percentage from titanium diboride, titans ar bid, tantalum carbide ■ and / or zirconium carbide and 5 "to 15 percent by volume Molybdenum or tungsten or mixtures of these metals with iron, cobalt or winding. 14 · Watch case according to claim 13, characterized in that the mass is nitride titanium nitride, boride or car bid titanium carbide and, as metal, molybdenum, tungsten or mixtures this contains metals with nickel. - 35 109852 / OOU