Equipment for investigation of cryogenic compaction of nanosize silicon nitride powders
- National Inst. of Standards and Technology (MSEL), Gaithersburg, MD (United States). Ceramics Div.
- Air Force Office of Scientific Research, Washington, DC (United States)
- Rutgers--the State Univ., Newark, NJ (United States)
This paper describes a system for studies of time-dependent compaction of nanosize silicon nitride powders under various atmospheres at 77 to 1000 K. The system incorporates a screw-driven press (10 ton capacity) with a piston-cylinder type die and can produce cylindrical powder compacts, 3 mm dia and about 1 mm thick, using pressures up to 3 GPa. The system is computer-controlled and permits accurate measurements of the sample volume, and, after appropriate calibration, can determine the rate and degree of densification of the compacting powder as pressure is applied. Frictional forces between the piston and the die are measured during the compaction process. For calibration of the system, powders with known volume-change accompanied by phase transition under pressure were studied, and good agreement with published results was demonstrated. Several Si{sub 3}N{sub 4} samples have been compacted and sintered at 1300 to 1600{degrees}C. Max random packing density of 64% has been obtained using liquid nitrogen lubricant at pressure less than 2.5 GPa. Both green samples and samples sintered at temperatures to 1500{degrees}C were transparent.
- Research Organization:
- National Inst. of Standards and Technology (MSEL), Gaithersburg, MD (United States). Ceramics Div.
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AI05-92OR22041
- OSTI ID:
- 10171426
- Report Number(s):
- DOE/OR/22041--1; ON: DE93018740
- Country of Publication:
- United States
- Language:
- English
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