INVESTIGATION OF HIGH TEMPERATURE RESISTANT MATERIALS

X-ray diffraction studies showed that for slipcast fused silica impregnated with AlCl3 the percentage bulk of cristobalite was reduced from 73.3% to 4.2% after 3 cycles following revised firing and impregnation procedures. Fused silica substrates could not be coated with alumina using conventional arc-spraying techniques. Procedures for arc-plasma flame glazing on fused silica are reported; average transverse strength over unglazed samples was increased 34%. Water absorption determinations indicated that the slipcast fused silica surfaces can be sealed by arcplasma glazing. F-40 Arc Plasma Unit alumina particle melting studies demonstrated that more complete particle melting took place when the high enthalpy-low velocity nozzle was used instead of the conventional No. 3 spray nozzle. Particles sprayed with the latter exploded on contact with water. Other studies included work on thermal shock, radome fabrication, and NOL sample evaluation in oxyhydrogen rocket motor exhaust.