摘要:
A method of forming a low level carbon high-density tungsten carbide-containing material includes sintering a preform which contains tungsten carbide powder and has a composition such that the resulting sintered material has at most 6.05 weight percent tungsten-bound carbon based on the total weight of tungsten and tungsten-bound carbon. This low level of carbon may be achieved by, prior to the sintering step, oxidizing the tungsten carbide powder sufficiently to achieve the desired substoichiometric carbon level in the sintered product or by adding a carbon-lowering material selected from the group consisting of tungsten, ditungsten carbide, and tungsten oxide. Optionally, other materials can be present in the preform such as carbon-getter metals and compounds thereof. The carbon-getter metals are those metals of which the carbides thereof are more thermodynamically stable than monotungsten carbide.
摘要:
A tungsten carbide-containing material in which the tungsten carbide has the general formula, W.sub.x C, wherein x is greater than one and less than two and the material has less than 0.20 weight percent cobalt, a density of at least about 97% of its theoretical density, and a Vickers hardness of at least about 2400 kg/mm.sup.2.
摘要翻译:一种含碳化钨的材料,其中碳化钨具有通式W x C,其中x大于1且小于2,并且该材料具有小于0.20重量百分比的钴,密度至少为其理论值的约97% 密度,维氏硬度至少约2400kg / mm2。
摘要:
A process for preparing complex-shaped, ceramic-metal composite articles, comprising:a) contacting a non-wettable powder that is non-wetting to a metal to be used for infiltration with a shaped ceramic body to form a layer(s) of the non-wettable powder on one or more surface(s) of the shaped ceramic body wherein the shaped ceramic body has a region(s) where there is no layer of the non-wettable powder;b) infiltrating the shaped ceramic body with the metal through the region(s) where there is no layer of the non-wettable powder such that a complex-shaped ceramic-metal composite comprising one or more metal phases and one or more ceramic phases is formed, wherein the article has substantially the net shape of the shaped ceramic body and the undesirable regions of excess metal on the surface and undesirable phases within the complex-shaped ceramic-metal composite article near the surface are located only in the region(s) where there is no layer of the non-wettable powder.A complex-shaped ceramic-metal composite article with undesirable regions of excess metal and undesirable phases on the surface(s) of or within the article only where there is or was no layer of non-wettable powder.The process of the invention allows the preparation of complex-shaped ceramic-metal composite articles with undesirable regions of excess metal and undesirable phases on the surface(s) of or within the article only in the regions where there is or was no layer of non-wettable powder. The process of the invention allows the preparation of a complex-shaped ceramic-metal composite article which requires little or no machining of the surface(s) to achieve a finished article. A complex-shaped ceramic-metal composite article is prepared which contains few undesirable regions of excess metal and undesirable phases.
摘要:
A process for preparing complex-shaped, ceramic-metal composite articles, comprising: (a) contacting a non-wettable powder that is non-wetting to a metal to be used for infiltration with a shaped ceramic body to form a layer of the non-wettable powder on one or more surfaces of the shaped ceramic body, wherein the shaped ceramic body has a region where there is no layer of the non-wettable powder, and (b) infiltration the shaped ceramic body with the metal through the region or regions where there is no layer of the non-wettable powder, such that a complex-shaped ceramic-metal composite comprising one or more metal phases and one or more ceramic phases is formed, wherein the article has substantially the net shape of the shaped ceramic body and undesirable regions of excess metal on the surface and undesirable phases within the complex-shaped ceramic-metal composite article near the surface are located only in the region or regions where there is no layer of the non-wettable powder. The process of the invention allows the preparation of complex-shaped ceramic-metal composite articles with undesirable regions of excess metal and undesirable phases on the surface(s), of, or within, the article only in the regions where there is, or was, no layer of non-wettable powder. The process of the invention allows the preparation of a complex-shaped ceramic-metal composite article which requires little or no machining of the surface(s) to achieve a finished article. A complex-shaped ceramic-metal composite article is prepared which contains few undesirable regions of excess metal and undesirable phases.
摘要:
An electrically conductive article including a substrate and at least one electrically conductive layer disposed on the substrate. The conductive layer may include a thermoplastic resin and from about 1 to 30 weight percent of at least one conductive additive based on a total weight of the thermoplastic resin and the at least one conductive additive. The conductive article may have a surface resistance between 0.001 to 20Ω at a test distance of 2.54 cm (1 inch).
摘要:
Disclosed is an electrically conductive thermoplastic polymer composition comprising a thermoplastic polymer and a synergistic combination of metal fibers and metal-coated fibers, structures made therefrom, and a process to make said compositions and structures.
摘要:
Alkenyl aromatic polymer foam comprising a polymer matrix containing one or more polymer and defining a plurality of cells having an average cell size wherein: (a) the alkenyl aromatic polymer foam has: —(i) an average cell size that is in a range of 0.02 and 5 millimeters; —(ii) a density of 64 kilograms per cubic meter or less; —(iii) an open cell content less than 30 percent; and —(iv) a cell size variation of 30% or less; and wherein the foam further comprises one or more fluorinated alkene blowing agent at a concentration of 0.03 moles or more and 0.3 moles or less per 100 grams of polymer foam.
摘要:
A ceramic-metal composite that is tough and stiff has been prepared and is comprised of an inert ceramic (e.g., alumina) embedded and dispersed in a matrix comprised of a metal (e.g., aluminum), a reactive ceramic (e.g., boron carbide) and a reactive ceramic-metal reaction product (e.g., AlB2, Al4BC, Al3B48C2, AlB12, Al4C3, AlB24C4 or mixtures thereof) wherein grains of the inert ceramic have an average grain size greater than or equal to the average grain size of grains of the reactive ceramic. The ceramic-metal composite may be prepared by forming a mixture comprised of an inert ceramic powder (e.g., alumina) and a reactive ceramic powder (e.g., boron carbide), the inert ceramic powder having an average particle size equal to or greater than the average particle size of the reactive ceramic powder, forming the mixture into a porous body and consolidating the porous body in the presence of a metal (e.g., aluminum) to form the ceramic-metal composite.
摘要:
An improved coating composition including a polymeric component and synthetic clay. The coating composition is particularly useful for coating a polymeric substrate, such as a styrenic polymeric substrate. One particular preferred application involves coating a closed cell foam extruded styrenic polymeric insulation panel with the coating composition, thereby realizing attractive barrier properties and optical characteristics from the coating.
摘要:
The invention is a complex-shaped article, comprising an article prepared by joining at least one multi-phase ceramic-metal part and at least one shaped part of another material, wherein the theoretical density of the at least one ceramic-metal part is greater than 80 percent.In another aspect, the invention is a process for preparing complex-shaped articles, comprising:(a) forming at least one ceramic-metal part;(b) forming at least one shaped part of another material; and(c) joining the at least one shaped ceramic-metal part with the at least one shaped part of another material such that a complex-shaped article is formed.The invention is a less costly and time-consuming process for preparing complex-shaped composite articles wherein the articles are formed of two or more selected materials wherein one of the materials is a ceramic-metal composite.