Accession Number : ADA018163

Title :   Optimal Densification of Ceramics by Rate Controlled Sintering.

Descriptive Note : Final rept. Feb 74-Jun 75,

Corporate Author : NORTH CAROLINA STATE UNIV RALEIGH ENGINEERING RESEARCH SERVICES DIV

Personal Author(s) : Palmour,H. , III ; Hare,T. M.

Report Date : JUL 1975

Pagination or Media Count : 79

Abstract : The rate controlled sintering characteristics of (a) 99.9% Al2O3, (b) 99.9% MgAl2O4 and (c) a BaTiO3-CaZrO3 composition have been studied in comparison with conventional isothermal treatments. Process steps which precede firing of about 99.9% Al2O3 ceramics were shown to exert an important influence upon final microstructures; improvements attributed to preprocess optimization were found to be effective with both conventional and rate controlled sintering regimes. Through successive step-by-step optimizations, a novel dry process sequence has been evolved which incorporates (a) dry millng (b) introduction of fugitive organic binder and lubricant phases, (c) remilling, (d) granulation, (e) preforming by dry pressing, (f) isostatic re-pressing and (g) controlled binder burnout. These optimizations of particulate processing and of density-time profiles have been undertaken primarily in the engineering sense: it has been demonstrated that they provide practical means for establishing rational engineering control of densification dynamics.

Descriptors :   *Sintering, *Ceramic materials, Alumina, Magnesium compounds, Aluminates, Spinel, Barium titanates, Calcium compounds, Zirconates, Density, Microstructure, Defects(Materials), Lubricants

Subject Categories : Ceramics, Refractories and Glass

Distribution Statement : APPROVED FOR PUBLIC RELEASE