Accession Number : ADA317936

Title :   Ceramic Bearing Specimen Technology.

Descriptive Note : Interim rept. 1 Feb 92-1 Jul 93,

Corporate Author : CERCOM INC VISTA CA

Personal Author(s) : Shih, C. J. ; McCoy, John W. ; Ezis, Andre

PDF Url : ADA317936

Report Date : DEC 1993

Pagination or Media Count : 163

Abstract : A manufacturing process for a silicon nitride bearing material is developed. The process involves powder homogenization, pre-nitriding, high-speed green machining, reaction bonding, pressureless sintering and containerless hot isostatic pressing. Extensive experimental and analytical tasks are performed in each process step to develop a low-cost, reliable silicon nitride bearing material with a uniform microstructure and a premium quality. Low-cost silicon powder is used as a raw material. A quality assurance procedure is developed to examine the powder homogeneity in the blended powder. Conditions for the pre-nitriding are defined to provide powder compacts with sufficient strength for the high-speed green machining. The reaction bonding process converts silicon to silicon nitride completely. It is demonstrated that silicon nitride can be sintered in a non-reactive gas environment. Processing parameters for the hot isostatic pressing are optimized to control thermal decomposition and gas dissolution-evolution reactions to fabricate the pore-free bearing material without using a glass encapsulant.

Descriptors :   *CERAMIC MATERIALS, *SILICON NITRIDES, THERMAL PROPERTIES, MICROSTRUCTURE, ENVIRONMENTS, MANUFACTURING, LOW COSTS, MACHINING, POWDERS, PROCESSING, HIGH VELOCITY, ISOSTATIC PRESSING, GLASS, GASES, PRESSURE, ENCAPSULATION, BONDING, QUALITY ASSURANCE, PYROLYSIS, HOMOGENEITY, SINTERING.

Subject Categories : Ceramics, Refractories and Glass
      Inorganic Chemistry
      Mfg & Industrial Eng & Control of Product Sys

Distribution Statement : APPROVED FOR PUBLIC RELEASE