EFFECTS OF LOW PRESSURE-HIGH TEMPERATURE CONDITION ON THE LIFE OF SILICONIZE COATINGS.
MCDONNELL AIRCRAFT CORP ST LOUIS MO
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Protective coatings have been developed to prevent the catastrophic oxidation of refractory metals when exposed to oxygen at extreme operating temperatures. Oxidation tests at low pressure were conducted to determine the effectiveness of TRW Tapco, Chromalloy W-3, and McDonnell LB-2 coatings applied to various metal substrates when subjected to the expected temperatures of reentry conditions. No definite comparison was attempted between the oxidation prevention of the various coatings because each was subjected to the maximum temperature it was expected to attain during operation, and in each case the temperature varied. Only one failure was observed during these tests. This was in the case of Chromalloy W-3 applied to unalloyed molybdenum however, the same coating applied to TZM molybdenum alloy successfully withstood similar test conditions. Author