Accession Number : AD0717983

Title :   Chemical Strengthening of Ceramic Materials.

Descriptive Note : Summary rept. 7 Jan-6 Dec 70,

Corporate Author : CERAMIC FINISHING CO STATE COLLEGE PA

Personal Author(s) : Kirchner,Henry P. ; Buessem,W. R. ; Gruver,Robert M. ; Platts,Dennis R. ; Walker,Ralph E.

Report Date : 06 DEC 1970

Pagination or Media Count : 166

Abstract : In polycrystalline ceramics subjected to external forces fracture originates at surface flaws. Compressive surface layers prevent surface flaws from acting to cause failure. Therefore, compressive surface layers can be used to obtain improved strengths. In the investigation, treatments were applied to alumina, zirconium diboride, silicon carbide and zircon porcelain bodies. The methods used included quenching, glazing and quenching, formation of low expansion surface layers by reaction with powders at high temperatures, and chemical vapor deposition of low expansion surface layers. Glazing and quenching improved the strength of 96% alumina body. Preliminary evidence of strengthening by chemical vapor deposition of surface layers was obtained. Other properties of the treated materials that were determined included the elevated temperature flexural strength and the impact resistance. Fractographic techniques were used to investigate the fracture mechanisms and the fracture origins. Residual stress profiles were calculated and were used to calculate the outer fiber stress and the stress at the volume flaws. (Author)

Descriptors :   (*CERAMIC MATERIALS, *FINISHES), (*SURFACE PROPERTIES, CERAMIC MATERIALS), DEFECTS(MATERIALS), ALUMINA, SILICON CARBIDES, ZIRCONIUM COMPOUNDS, BORIDES, QUENCHING, VAPOR PLATING, FRACTURE(MECHANICS), IMPACT TESTS, STRESSES, SILICATES, MECHANICAL PROPERTIES

Subject Categories : Ceramics, Refractories and Glass
      Coatings, Colorants and Finishes

Distribution Statement : APPROVED FOR PUBLIC RELEASE