Materials Research for Advanced Inertial Instrumentation. Task 2. Gas Bearing Material Development.
Abstract
Progress is reported on three fronts: Boron deposition on beryllium by chemical vapor deposition (CVD) and subsequent reactive diffusion of the deposited boron film, ion implantation of boron into beryllium, and beryllium-ceramic composite materials. CVD coatings of boron, from B2H6 on beryllium at 700 C showed less tendency to crack and spall at a 5 micron thickness than did previous coatings 1 micron thick which had been deposited at 900 C and 950 C. Hardness also increased for the lower temperature thicker films; 2500 KHN versus 1400 KHN. Improved beryllium surface coverage resulted from redesigning the CVD processing chamber to minimize oxygen contamination by providing for vacuum bake out. Films of 10 micron, 3000 KHN, are now obtained without cracking or spalling. metallography electron diffraction and Auger analysis suggest that the coatings consist of an amorphous outer layer of boron with a lyaer of mixed beryllium borides at the interface. Heat treatment at 900 C for several hours brought about conversion to BeB6. Future studies will use more rigorous conditions in an attempt to form BeB2, with the objective of allowing selection of B, BeB2, or BeB6 as a gas bearing surface. Emphasis will also be placed on generation of new information pertaining to diffusion kinetics in the Be-B system.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1980
- Accession Number
- ADA098229
Entities
People
- Debanik Das
- E. Wettstein
- J. Wollam
- K. Kumar
Organizations
- Charles Stark Draper Laboratory