EFFECT OF SULFUR IN JP-5 FUEL ON HOT CORROSION OF COATED SUPERALLOYS IN MARINE ENVIRONMENT.
Final summary rept. 1 Apr 66-31 Mar 67,
PHILLIPS PETROLEUM CO BARTLESVILLE OK RESEARCH DIV
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Specimens of a nickel-base alloy Inconel 713C and the alloy with an aluminum-diffusion coating Misco MDC-1 or with an aluminum-chromium-diffusion coating Misco MDC-9 were tested using a high-pressure combustor facility to simulate environment in the turbine section of an aircraft engine. Tests were conducted at 2000 F gas temperature, without sea salt and with 1.0 ppm sea salt in air, using three levels of sulfur in fuel 0.40, 0.040 and 0.0040 per cent by weight. A significant decrease in the relative rate of corrosion when sea salt was removed from the air indicated that sea salt is a primary cause in the hot corrosion of both bare and coated superalloys in a marine environment. The effect of sulfur in fuel varied with the coating and the absence or presence of sea salt. In the absence of sea salt, a reduction in sulfur from the present limit of 0.40 per cent for JP-5 fuel to either 0.040 or 0.0040 decreased attack with one coating, increased attack with the other coating, and had no significant effect with the uncoated superalloy. In the presence of 1.0 ppm sea salt in air, a reduction in sulfur to 0.040 per cent had no significant effect on attack however, a further reduction to 0.0040 per cent decreased the relative rate of attack with both coated superalloys, as well as with the bare superalloy. Author
- Fabrication Metallurgy