Accession Number : AD0778373

Title :   Production and Formation of Si3N4 from Precursor Materials.

Descriptive Note : Annual rept. (Final), Mar-Dec 73,

Corporate Author : FRANKLIN INST RESEARCH LABS PHILADELPHIA PA

Personal Author(s) : Morgan,Peter E. D.

Report Date : 30 MAR 1974

Pagination or Media Count : 29

Abstract : A region of rapid densification during the hot-pressing of amorphous silicon nitride at around 1490C has been discovered coincident with the crystallization to mostly alpha silicon nitride. The possibility exists that fully dense pure silicon nitride can be formed without the need for any additives by making use of this enhanced densification effect. The phase relationships between the alpha and beta forms have continued to defy simple explanation. However, a tentative explanation of the relationship of alpha and beta Si3N4 is put forward on the basis of conflicting sigma and pi orbital overlap requirements in multiply bonded Si and N. (Author)

Descriptors :   *Silicon nitrides, Hot pressing, Silicon compounds, Imides, Chemical reactions, Density, Precursors

Subject Categories : Ceramics, Refractories and Glass

Distribution Statement : APPROVED FOR PUBLIC RELEASE