Abstract: An article that includes a substrate and an amorphous, covalently-bonded layer on the surface of the substrate. The substrate may be a crystalline ceramic and/or may have a surface with a first surface roughness (Ra) of at least 100 angstroms, and the amorphous, covalently-bonded layer has a second surface roughness (Ra) of up to 15 angstroms. The substrate may have a dimension of at least 50 mm, and the amorphous, covalently-bonded layer may have a thickness of at least five micrometers. A method of making an article is also disclosed. The method includes forming an amorphous, covalently-bonded layer on the surface of the substrate by plasma deposition and, in some embodiments, polishing the amorphous, covalently-bonded layer to a second surface roughness (Ra) of up to 15 angstroms. The amorphous, covalently-bonded layer in the article and method includes silicon, oxygen, carbon, and hydrogen atoms.

Abstract: A silicon nitride material is disclosed which has properties beneficial for efficient operation of a corona discharge igniter system in an internal combustion gas engine.

Abstract: A silicon nitride material is disclosed which has properties beneficial for efficient operation of a corona discharge igniter system in an internal combustion gas engine.

Abstract: A silicon nitride material is disclosed which has properties necessary for efficient operation of a corona discharge igniter system in an internal combustion gas engine allowing an increase in fuel efficiency of over 10%. The material is disclosed in a range of compositions, all of which exhibit high dielectric strengths, high mechanical strength, thermal shock resistance and fracture toughness, low dielectric constant and loss tangent and electrical resistivity, all of which significantly increase the efficiency of the igniter system over current state of the art alumina insulators. Moreover, the materials retain their dielectric strength and structural integrity at elevated temperatures, up to 800° C.-1000° C. One embodiment comprises a sintered silicon nitride process comprising powder batching, binder removal and sintering. In the preferred embodiment the method of manufacture for silicon nitride is an SRBSN process comprising powder batching, powder pressing, binder removal, nitriding and sintering.

Abstract: Silicon nitride materials with high strength, fracture toughness values, and Weibull moduli simultaneously, due to unique large grain reinforcing microstructures and well engineered grain boundary compositions. The invention demonstrates that, surprisingly and contrary to prior art, a silicon nitride material can be made which simultaneously has high strength above about 850-900 MPa, a Weibull above about 15 and high fracture toughness (above about 8 and 9 MPa·m1/2), and has reinforcing grains longer than 5 ?m, typically longer than 10 ?m in the microstructure without compromising its properties and reliability. The product of this invention can be processed using a variety of densification methods, including gas-pressure sintering, hot pressing, hot isostatic pressing, but is not limited to these, and does not require multiple heat treatments for all of these features to be achieved.

Abstract: A method of increasing mean time between cleans of a plasma etch chamber and chamber parts lifetimes is provided. Semiconductor substrates are plasma etched in the chamber while using at least one sintered silicon nitride component exposed to ion bombardment and/or ionized halogen gas. The sintered silicon nitride component includes high purity silicon nitride and a sintering aid consisting of silicon dioxide. A plasma processing chamber is provided including the sintered silicon nitride component. A method of reducing metallic contamination on the surface of a silicon substrate during plasma processing is provided with a plasma processing apparatus including one or more sintered silicon nitride components. A method of manufacturing a component exposed to ion bombardment and/or plasma erosion in a plasma etch chamber, comprising shaping a powder composition consisting of high purity silicon nitride and silicon dioxide and densifying the shaped component.

Abstract: A silicon nitride material is disclosed which has properties necessary for efficient operation of a corona discharge igniter system in an internal combustion gas engine allowing an increase in fuel efficiency of over 10%. The material is disclosed in a range of compositions, all of which exhibit high dielectric strengths, high mechanical strength, thermal shock resistance and fracture toughness, low dielectric constant and loss tangent and electrical resistivity, all of which significantly increase the efficiency of the igniter system over current state of the art alumina insulators. Moreover, the materials retain their dielectric strength and structural integrity at elevated temperatures, up to 800° C.-1000° C. One embodiment comprises a sintered silicon nitride process comprising powder batching, binder removal and sintering. In the preferred embodiment the method of manufacture for silicon nitride is an SRBSN process comprising powder batching, powder pressing, binder removal, nitriding and sintering.

Abstract: Silicon nitride materials with high strength, fracture toughness values, and Weibull moduli simultaneously, due to unique large grain reinforcing microstructures and well engineered grain boundary compositions. The invention demonstrates that, surprisingly and contrary to prior art, a silicon nitride material can be made which simultaneously has high strength above about 850-900 MPa, a Weibull above about 15 and high fracture toughness (above about 8 and 9 MPa·m1/2), and has reinforcing grains longer than 5 ?m, typically longer than 10 ?m in the microstructure without compromising its properties and reliability. The product of this invention can be processed using a variety of densification methods, including gas-pressure sintering, hot pressing, hot isostatic pressing, but is not limited to these, and does not require multiple heat treatments for all of these features to be achieved.

Abstract: A dense silicon carbide (SiC) material with boron (B), nitrogen (N) and oxygen (O) as the only additives and with excellent insulting performance (electrical volume resistivity greater than 1×108 ?·cm). The SiC ceramic material, made from a powder mix of, by weight, from 0.1 to 7% boron carbide, from 0.1 to 7% silicon nitride, from 0.1 to 6% silicon dioxide, and a balance of ?-SiC, consists essentially of (1) at least 90% by weight of ?-SiC, (2) about 0.3 to 4.0% by weight of boron, (3) about 0.1 to 6.0% by weight of nitrogen, (4) about 0.06 to 0.5% by weight of oxygen, and (5) no more than 0.07% by weight of metallic impurities; wherein the boron and nitrogen are present according to an B/N atomic ratio of 0.9 to 1.5. In particular, this material is suitable for applications in plasma etching chambers for semiconductor and integrated circuit manufacturing.

Abstract: High-volume, fully dense, multi-component monoliths with microstructurally indistinguishable joints that can be used as refractory, corrosion and wear resistant components in the non-ferrous metal industry. The Si3N4 monoliths according to the invention comprise at least 90% by weight ?-type Si3N4 and up to 10% by weight of a predominantly amorphous binder phase, said binder phase being formed from compositions of the rare earth metal —Al—Si—O—N, rare earth metal —Mg—Si—O—N or Mg—Si—O—N systems. Preferably the rare earth metal is yttrium (Y). The monoliths have a volume of greater than 250 cm3. A method of making the multi-component monoliths is achieved by simultaneously joining and uniaxially hot pressing an assembly of reaction bonded silicon nitride bodies (RBSN bodies). RBSN bodies are placed in contact with each other in the substantial absence of any interlayer or ceramic paste in between.

Abstract: A method of increasing mean time between cleans of a plasma etch chamber and chamber parts lifetimes is provided. Semiconductor substrates are plasma etched in the chamber while using at least one sintered silicon nitride component exposed to ion bombardment and/or ionized halogen gas. The sintered silicon nitride component includes high purity silicon nitride and a sintering aid consisting of silicon dioxide. A plasma processing chamber is provided including the sintered silicon nitride component. A method of reducing metallic contamination on the surface of a silicon substrate during plasma processing is provided with a plasma processing apparatus including one or more sintered silicon nitride components. A method of manufacturing a component exposed to ion bombardment and/or plasma erosion in a plasma etch chamber, comprising shaping a powder composition consisting of high purity silicon nitride and silicon dioxide and densifying the shaped component.

Abstract: A dense silicon carbide (SiC) material with boron (B), nitrogen (N) and oxygen (O) as the only additives and with excellent insulting performance (electrical volume resistivity greater than 1×108 ?.cm). The SiC ceramic material, made from a powder mix of, by weight, from 0.1 to 7% boron carbide, from 0.1 to 7% silicon nitride, from 0.1 to 6% silicon dioxide, and a balance of ?-SiC, consists essentially of (1) at least 90% by weight of ?-SiC, (2) about 0.3 to 4.0% by weight of boron, (3) about 0.1 to 6.0% by weight of nitrogen, (4) about 0.06 to 0.5% by weight of oxygen, and (5) no more than 0.07% by weight of metallic impurities; wherein the boron and nitrogen are present according to an B/N atomic ratio of 0.9:1 to 5:1. In particular, this material is suitable for applications in plasma etching chambers for semiconductor and integrated circuit manufacturing.

Abstract: High-volume, fully dense, multi-component monoliths with microstructurally indistinguishable joints that can be used as refractory, corrosion and wear resistant components in the non-ferrous metal industry. The Si3N4 monoliths according to the invention comprise at least 90% by weight ?-type Si3N4 and up to 10% by weight of a predominantly amorphous binder phase, said binder phase being formed from compositions of the rare earth metal —Al—Si—O—N, rare earth metal —Mg—Si—O—N or Mg—Si—O—N systems. Preferably the rare earth metal is yttrium (Y). The monoliths have a volume of greater than 250 cm3. A method of making the multi-component monoliths is achieved by simultaneously joining and uniaxially hot pressing an assembly of reaction bonded silicon nitride bodies (RBSN bodies). RBSN bodies are placed in contact with each other in the substantial absence of any interlayer or ceramic paste in between.

Abstract: This disclosure describes sintered bodies comprising about 90 wt % to about 99 wt % of boron carbide, having a B:C atomic ratio ranging from 3.8 to 4.5:1; 0 to 1 wt % free carbon; 0 to 1 wt % BN or AlN, remainder an oxide binder phase; said sintered body having a uniform microstructure composed of substantially equiaxed grains of said boron carbide; the oxide binder phase comprising at least a rare earth aluminate and optionally Al2O3 or other ternary or binary phases of rare earth oxide-alumina systems; the binder phase being present in form of pockets at the multiple grain junctions and the density of no more than 2.6 g/cm3. Also described is a manufacturing process for the above described substantially pore-free, sintered boron carbide materials with high strength and fracture toughness, which can be used for production of large-area parts. This is achieved by liquid phase low temperature-low pressure hot pressing of boron carbide in an argon atmosphere.

Abstract: This disclosure describes sintered bodies comprising about 90 wt % to about 99 wt % of boron carbide, wherein the B:C atomic ratio ranges from 3.8 to 4.5:1; 0 to 1 wt % free carbon; 0 to 1 wt % BN or AlN, remainder an oxide binder phase; said sintered body having a uniform microstructure composed of substantially equiaxed grains of said boron carbide; the oxide binder phase comprising a least a rare earth aluminate and optionally other ternary or binary phases of rare earth oxide—alumina systems; the binder phase being present in form of pockets at the multiple grain junctions and the density of no more than 2.6 g/cm3. Also described is a manufacturing process for the above described substantially pore-free, sintered boron carbide materials with high strength and fracture toughness, which can be used for production of large-area parts. It is achieved by liquid phase low temperature—low pressure hot pressing of boron carbide in an argon atmosphere.

Abstract: Dense composites of dielectric material having high thermal conductivity and adjustable dielectric properties. The dense composites are composed of homogeneous mixtures of AlN and SiC with at least one member selected from the group consisting of Y2O3, La2O3, rare earth oxides, CaO and Li2O. These composites are ideally shaped into usable products such as traveling wave tubes and electronic accelerators for use in microwave environments.

Abstract: A monolithic silicon nitride material and a method of manufacturing the material. The material is disclosed in a range of composition variations all of which exhibit high dielectric strengths suitable for use in insulator applications. Moreover, the material retains its dielectric and structural integrity even at elevated temperature, such as above 800 degrees Celsius. One embodiment of the method of manufacture is an SRBSN process comprising powder batching, powder pressing, binder removal, nitriding and sintering. The second embodiment is an SSN process comprising powder batching, binder removal and sintering. In either embodiment, the resulting Si3N4 composition also comprises up to 20% by weight of Al2O3, up to 15% by weight rare earth oxides and up to 5% by weight of other constituents.

Abstract: An aluminum nitride (AlN), alumina, magnesia, beryllia or other dielectric matrix with a ZrC dispersed phase is provided. Mixed powders of aluminum nitride or other dielectric phases and ZrC, with or without Y2O3, CaO, Li2O, La2O3, and other rare earth metal oxides or mixtures thereof are formed by dry pressing (or isostatic pressing, injection molding or other similar methods known to those familiar with the art). Consolidation at high temperatures (and or pressures) to a virtually dense material with densities of over 95%, preferably higher than 97% of theoretical density can be attained by hot pressing, hip-ing, gas-pressure sintering or pressureless sintering (including microwave sintering). A controlled inert atmosphere is required to prevent the oxidation or other reaction of the carbide phase. Ar or similar atmosphere is preferred to avoid reactions with ZrC.

Abstract: Dense, high thermal conductivity AIN ceramic is described (along with a method of manufacture) which can be used in microwave tubes as collector rods, Helix support rods, T rods, etc. instead of BeO ceramic. High thermal conductivity, vacuum compatibility, low dielectric loss tangent at microwave frequencies, high electrical resistivity and dielectric strength are AIN properties allowing the material to be used in traveling wave tubes, particle accelerators or as laser bores and in other similar applications. These materials allow the replacement of BeO, which is a toxic material with diminishing availability in the United States and on the world market.