Accession Number : AD0665315

Title :   HIGH PRESSURE HOT PRESSING OF REFRACTORY MATERIALS.

Descriptive Note : Technical rept.,

Corporate Author : MANLABS INC CAMBRIDGE MASS

Personal Author(s) : Kalish,David ; Clougherty,Edward V.

Report Date : JAN 1968

Pagination or Media Count : 37

Abstract : The densification of powdered refractory materials by hot pressing at high pressures and high temperatures provides a means of preparing high purity, fine-grained fully dense microstructures. Pressures of the order of 100,000 psi greatly enhance consolidation processes as compared to conventional hot pressing or pressureless sintering. Densification of refractory borides, carbides, oxides and metals is achieved at relatively low temperatures within 10 minutes. The closed high pressure hot pressing system and low temperatures are particularly important for materials subject to preferential vaporization of one component, highly reactive materials, or limiting grain growth of submicron powders. The roles of fabrication temperature, fabrication pressure and powder degassing procedures on high pressure hot pressed microstructures are considered in detail. Techniques are discussed for controlling the stoichiometry and phase distribution in high pressure hot pressed microstructures formed from reactive powder mixtures. (Author)

Descriptors :   (*REFRACTORY MATERIALS, *HOT PRESSING), HIGH PRESSURE, POWDERS, COMPACTING, MICROSTRUCTURE, BORIDES, CARBIDES, OXIDES, TUNGSTEN, DENSITY, POROSITY, DEGASIFICATION

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

Distribution Statement : APPROVED FOR PUBLIC RELEASE