Abstract: A method of depositing a polycrystalline diamond layer on a nitride substrate is disclosed, which comprises chemically-etching the nitride substrate with a KOH or NaOH solution or melt and depositing the polycrystalline diamond layer on the nitride substrate from a vapor phase, wherein the etching temperature, time and concentration of the etchant are controlled so that at least 75% of the interface between the substrate and the diamond layer is covered by diamond crystals, each diamond crystal having a contact area with the substrate of .gtoreq.20 um.sup.2.

Abstract: A composite powder particle, consisting of a core and a coating, and consisting either completely or partly of a superhard matter different from that of the core, and being prepared by means of a special method, at which the superhard matter is at least partly formed from a gaseous phase at sub-pressure and at temperatures below 1200.degree. C.

Abstract: A composite element is disclosed, having improved heat conductivity, and is composed of a substrate whose surface layer enables homeo- or heteroepitactic growth of the diamond lattice from the gas phase, and of a low pressure diamond layer grown on the substrate, and in which the diamond layer grown is enriched compared to the normal diamond composition in the carbon isotope C.sup.12 and depleted in the heavier carbon isotopes C.sup.13 and C.sup.14.

Abstract: The present invention relates to a compound body consisting of a substrate with a surface coating of one or more dense, finegrained diamond layers, where the diamond grains are directly bonded to each other. Extreme hardness makes the compound body suitable for wear parts- and tools applications. Very good heat conductivity and an extremely high electrical isolation resistance makes the compound body extremely useful to lead away heat in electronic components.

Abstract: A chemical vapor deposition method for the production of a composite body with one or more polycrystalline diamond layers, essentially free of intercrystalline binder phase, on a substrate of one of: (a) metalbonded hardmaterial compound; (b) ceramic material; or (c) a metal or an alloy, whereby the heated substrate is contacted with a gaseous mixture of hydrocarbon or hydrogen, which mixture has been activated by passing it over a tantalum heater heated to a temperature of 1500.degree.-2500.degree. C.Also disclosed is the use of the compound body in tools subjected to mechanical operations.

Abstract: The invention relates to a process for treating cast iron melts with silicon carbide. In this process, the silicon carbide used is subjected, before being introduced into the cast iron melt, to an oxidizing treatment in such a manner that the individual SiC granules are coated with a covering containing silica. A silicon carbide of this quality can be manufactured, for example, by subjecting the SiC in granular form, in a static or agitated mass, to an oxidizing atmosphere, such as air, oxygen or water vapor, at temperatures within the range of 900.degree.-1600.degree. C. and subsequently subjecting the agglomerates formed to gentle comminution to expose the SiC surfaces which, as a result of the formation of an agglomerate, completely or partially escaped the oxidizing attack.

Abstract: This invention concerns a cellular, spherical bead of organic, macromolecular polymer material which when carbonized in the solid state retains its original beaded shape and has a high carbon content and methods for making such beads of polymer and carbon.

Abstract: A metallic alloy is cast in a mold to produce a solid body by unidirectional solidification. The alloy, initially in a molten state, is cast into a mold and is completely and progressively cooled in the mold while a unidirectional thermal gradient superimposed thereon parallel to a direction determined by the configuration of the mold (predetermined direction) until a metastable equilibrium is reached in which the entire body of the melt is in a super-cooled state as a homogeneous liquid. The equilibrium is then broken to cause solidification of the alloy and the formation of dendritic crystals with their principal axes parallel to the thermal gradient substantially instantly and without noticeable advance of a solidification front across the melt.