Cold pressing of wurtzite boron nitride powders under high pressures

A study was made of the compressibility of wurtzite boron nitride powders containing various amounts of graphitelike boron nitride. For all the powders investigated the relationship between compact density and pressing pressure was found to be of the same type. It is shown that the densification of wurtzite boron nitride powders and, apparently, other powdered superhard materials under conditions of high pressures can be described by logarithmic or power expressions. The physical meaning of the constants of the powder pressing equations is explained. Pressures necessary for attaining some given structures and densities in the pressing of powdered superhard materials are estimated.