Abstract:
Polycrystalline cubic boron nitride compact include a body having sintered microcrystalline cubic boron nitride in a matrix of binder material. The microcrystalline cubic boron nitride particles have a size ranging from 2 microns to 50 microns. The particles of microcrystalline cubic boron nitride include a plurality of sub-grains, each sub-grain having a size ranging from 0.1 micron to 2 microns. The compacts are manufactured in a high pressure - high temperature (HPHT) sintering process. The compacts exhibit intergranular defect formation following introduction of wear. The sub-grains promote crack propagation based on micro-chipping rather than on a cleavage mechanism and, in sintered bodies, cracks propagate intergranularly rather than intragranularly, resulting in increased toughness and improved wear characteristics as compared to monocrystalline cubic boron nitride. The compacts are suitable for use as abrasive tools.
Abstract:
A carbon composite comprises a binder and carbon microstructures having interstitial spaces among the carbon microstructures and voids within carbon microstructures; wherein the binder is disposed in the interstitial spaces among the carbon microstructures and the voids within the carbon microstructures. Alternatively, a carbon composite comprises carbon microstructures and a binder disposed in the interstitial spaces among the carbon microstructures, wherein the carbon microstructures comprise less than about 15 volume percent of voids within the carbon microstructures based on the total volume of the carbon microstructures.
Abstract:
The invention is a low binder, wear resistant material including, in weight percent of raw materials, from 15 % to 20 % of molybdenum carbide added in either elemental or compound form, an alloy of 0.9 % to 3 % cobalt, nickel or a combination of cobalt and nickel, of 0 to 0.1 % of chromium carbide, optionally also titanium carbide or titanium tungsten carbide and the balance of tungsten carbide.
Abstract:
The present disclosure relates to ceramic matrix composites made by chemical vapor infiltration, methods of making the ceramic matrix composites, and ceramic matrix composite turbine components for use in a hot gas pathway. A method of fabricating a ceramic matrix composite is provided that can include the steps of: (i) forming a plurality of holes in a ceramic matrix composite preform of desired shape; and (ii) densifying the preform by a chemical vapor infiltration process to form a part or most of the matrix. A ceramic matrix composite is also provided that can be used in hot combustion gases made according to the aforementioned ceramic matrix composite fabrication method described herein.
Abstract:
L'invention concerne un procédé de fabrication de pièce en matériau composite, comprenant les étapes de : - réalisation d'une préforme fibreuse consolidée, les fibres de la préforme étant des fibres de carbone ou de céramique et étant revêtues d'une interphase, - obtention d'une préforme fibreuse consolidée et partiellement densifiée, la densification partielle comprenant la formation sur l'interphase d'une première phase de matrice obtenue par infiltration chimique en phase gazeuse, et - poursuite de la densification par infiltration de la préforme fibreuse avec une composition d'infiltration contenant au moins du silicium et au moins un autre élément apte à abaisser la température de fusion de la composition d'infiltration à une température inférieure ou égale à 1150°C.
Abstract:
A composition having nanoparticles of a refractory-metal carbide or refractory-metal nitride and a carbonaceous matrix. The composition is not in the form of a powder. A composition comprising a metal component and an organic component. The metal component is nanoparticles or particles of a refractory metal or a refractory-metal compound capable of decomposing into refractory metal nanoparticles. The organic component is an organic compound having a char yield of at least 60% by weight or a thermoset made from the organic compound. A method of combining particles of a refractory metal or a refractory-metal compound capable of reacting or decomposing into refractory-metal nanoparticles with an organic compound having a char yield of at least 60% by weight to form a precursor mixture.
Abstract:
An embodiment of the invention is a low binder, wear resistant material including, in weight percent of raw materials, from about 15% to about 20% of molybdenum carbide added in either elemental or compound form, an alloy of about 0.9% to about 3% cobalt, nickel or a combination of cobalt and nickel, of about 0 to about 0.1% of chromium carbide and the balance of tungsten carbide. Optionally, the low binder, wear resistant material may include materials such as titanium carbide, titanium tungsten carbide.
Abstract:
A polycrystalline cubic boron nitride (PcBN) is fabricated using a process of overlaying layers of cubic boron nitride (cBN) powder, where the layers have cBN mixed with various concentrations of a ceramic. The process of fabricating the PcBN includes depositing, in a refractory capsule, a carbide, a cubic boron nitride (cBN), and a mixture of cBN and a ceramic, then applying a high pressure and high temperature (HPHT) to the content of the refractory capsule. During the depositing step of the process, the concentration of cBN in the mixture of the cBN and ceramic is lower than the concentration of cBN that is in the layer below it. Upon applying HPHT, the carbide first diffuses across the cBN layer, and then diffuses across the layer with the mixture of the cBN and ceramic. After HPHT ends and the content of the refractory capsule cools, the process yields a PcBN having layers with various concentrations of cBN, and at least one cBN layer with a ceramic material.