EFFECT OF SULFUR IN JP-5 FUEL ON HOT CORROSION OF COATED SUPERALLOYS IN MARINE ENVIRONMENT.
Progress rept. no. 2, 1 Jul-30 Sep 66,
PHILLIPS PETROLEUM CO BARTLESVILLE OKLA RESEARCH DIV
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An experimental investigation is in progress to determine whether the 0.4 per cent by weight of sulfur allowed in JP-5 fuel is a safe level for the protection of coated superalloys, used in aircraft-turbine engines of advanced design, when operated in a marine environment. The Phillips 2-inch combustor test facility was used to simulate the environment in the turbine section of an aircraft engine with respect to temperature, velocity, pressure, and stoichiometry. Tests were conducted with a nickel-base alloy Inconel 713C having either an aluminum-diffusion coating Misco MDC-1 or an aluminum-chromium-diffusion coating Misco MDC-9 at all combinations of three levels of sulfur in fuel 0.0002, 0.040, and 0.40 weight per cent with two levels of sea salt in air zero and 1.0 ppm. Exponential equations of weight-loss with time have been developed from a preliminary analysis of incomplete data, and statistically-significant effects have been identified at a 95 per cent confidence level. In all comparisons the removal of sea salt from the air significantly decreased the rate of attack thus, indicating sea salt to be a primary-causative agent of hot corrosion. The effect of sulfur in fuel varied with the superalloy coating and the presence or absence of sea salt. In no case did a reduction of sulfur in fuel from the present limit to 0.040 weight per cent have a significant effect on the rate of attack however, in the presence of 1.0 ppm sea salt in air, a reduction to 0.0002 weight per cent sulfur in fuel significantly decreased the rate of attack on both coated superalloys. Author
- Properties of Metals and Alloys
- Jet and Gas Turbine Engines