Temperature resistant abrasive polycrystalline diamond bodies are described, intended for use as tools in various mechanical operations like turning, milling, drilling, sawing and drawing, having different additions, i.e. amount and composition, of binding, fluxing, catalyst metals at different distances from the working surface. Preferably the metal concentration of the polycrystalline diamond body is decreasing towards the working surface while the metal composition is varied in a way that gives a mechanically stiffer matrix that also has a lower thermal expansion. In one embodiment the diamond body is high pressure-high temperature-bonded to a supporting body, e.g. of cemented carbide, in order to facilitate the clamping of the tool. In another embodiment the diamond body is brazed to a supporting body or used in a surface-set rock drill bit, i.e. held by a braze metal. Especially good results have been obtained if the hard polycrystalline diamond body comprises three different homogeneous diamond layers on top of each other, each layer having its special amount and composition of relatively low-melting binding metal. These three diamond layers are bonded to each other and to the supporting body, if any, by using intermediate layers of the thickness 3-300 µm, consisting of more high-melting metals or other materials like nitrides or borides, etc. in order to lock in the low-melting binding metals and to prevent diffusion of these metals between the different diamond layers and between the supporting body and the nearest diamond layer.

Temperature resistant abrasive polycrystalline diamond bodies

A mass of diamond crystals contacting a mass of elemental silicon are confined within a pressure-transmitting medium. The resulting charge assembly is subjected to a pressure of at least 25 kilobars causing application of isostatic pressure to the contacting masses which dimensionally stabilizes them and increases the density of the mass of diamond crystals. The resulting pressure-maintained charge assembly is heated to a temperature sufficient to melt the silicon and at which no significant graphitization of the diamond occurs whereby the silicon is infiltrated through the interstices between the diamond crystals producing, upon cooling, an adherently bonded integral body.

Silicon carbide and silicon bonded polycrystalline diamond body and method of making it

A diamond composite heat spreader having a variable thermal conductivity gradient can improve control of heat transfer based on a specific application. A diamond-containing region of the heat spreader can contain diamond particles such that the diamond concentration and/or the diamond particle size a varied to produce a desired thermal conductivity gradient. Regions proximate to a heat source can have a higher thermal conductivity than regions further away from the heat source. Thin diamond films can also be used in conjunction with the particulate diamond in order to provide a region of maximum thermal conductivity adjacent a heat source. By providing a variable thermal conductivity gradient, more expensive materials such as diamond film and larger diamond particles can be selectively used in regions closer to a heat source, while allowing for cheaper smaller diamond particles and materials to be used farther away from the heat source where thermal conductivity can be lower without sacrificing overall performance.

Diamond composite heat spreader having thermal conductivity gradients and associated methods

A high thermal conductivity substrate is formed by making a sintered diamond composite and thereafter modifying the electrical properties of the composite by leaching graphite and other non-diamond materials from the composite and subsequently infusing the leached composite with material having known electrical properties. Alternatively, a diamond composite having high thermal conductivity known electrical properties if prepared and subsequently leached to remove graphite and other materials which interfere with the known electrical properties of the composite material.

High thermal conductivity substrate

A thermally conductive diamond metal composite consisting essentially of 5 to 80 volume percent diamond particles having a particle size ranging from about 1 to 50 μm and a metal matrix comprising a thermally conductive metal. Preferably, a fine metal powder having particle size below 53 microns is utilized as the source for the metal matrix.

High thermal conductivity metal matrix composite

A process for producing diamond-metallic materials comprising subjecting a system consisting of diamond powder and a metallic binder, to a pressure of 10 to 50 kbar. The metallic binder is not mixed with the diamond powder initially, but rather is contained as a separate entity in any portion of the diamond powder. After packing, the diamond powder and metallic binder are heated, still under pressure, to a temperature sufficient to melt the metallic binder. The molten metallic binder is caused by the pressure to fill the inter-grain pores of the packed diamond powder.

Modenov Vitaly Pavlovich

Papers

Process for producing diamond-metallic materials