Accession Number : ADD009219

Title :   Hot Pressing of Machinable Silicon Nitride-Boron Nitride Composite.

Descriptive Note : Patent Application,

Corporate Author : DEPARTMENT OF THE AIR FORCE WASHINGTON DC

Personal Author(s) : Mazdiyasni,Khodabaksh S

Report Date : 12 Nov 1981

Pagination or Media Count : 20

Abstract : In accordance with the present invention, there is provided a novel composition consisting essentially of silicon nitride and boron nitride. Also provided in accordance with the present invention is a method for fabricating a silicon nitride body which comprises the steps of (1) intimately mixing (a) a silicon compound selected from the group consisting of alpha silicon nitride, amorphous silicon nitride, and polymeric silicon diimide powders, (b) boron nitride and (c) a sintering aid selected from the group consisting of compounds of the formula MO2, M2O3, MH3 and MN, wherein M is an element of the lanthanide series; (2) placing the resulting mixture in a suitable compression zone, and (3) compressing and heating the mixture in the compression zone at an elevated pressure and temperature for a time sufficient to provide a resulting densified body. The resulting composites exhibit improved electrical and thermal shock behavior. Thus, the material provided in accordance with this invention has properties which make it suitable for varied applications such as hot structural components in high performance turbine and internal combustion engines, as well as for antenna windows and radomes. The resulting composites also can be machined using conventional carbide tooling.

Descriptors :   *Patent applications, *Composite materials, *Hot pressing, *Nitrides, Machining, Antenna windows, Silicon nitrides, Boron nitrides, Turbines, Inventions, Amorphous materials, Electrical properties, High temperature, High pressure, Shock, Carbides, Compression

Subject Categories : Laminates and Composite Materials

Distribution Statement : APPROVED FOR PUBLIC RELEASE