Hot Corrosion Resistant Aluminide Coatings of Controlled Composition for Nickel-Base Superalloys.
Final rept. 15 Jan 71-9 Jul 73,
SOLAR SAN DIEGO CALIF
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The objective of the program was to develop and evaluate new application techniques and aluminide coatings of controlled composition for improved hot corrosion resistance of nickel-base superalloys. Three cast nickel-base alloys were included in the coating development program Inco 713C, B1900 and TRW or NASA VIA. Procedures and techniques were developed for applying modified elements of known composition onto nickel-base alloys followed by aluminizing to form the beta NiAl aluminide. The modifying elements evaluated were Cr, Co, Y, La, Nd, Gd, Mischmetal, Ti, Zr, Si, Al2O3, MgO, Mo, W, Ta, and several combinations of the above refractory, reactive, and rare earth metals. A crucible sulfidation test using 95Na2SO4-5NaCl at 1750F was the principal screening test used during coating development. Oxidation tests at 1750F and 2000F and ballistic impact tests followed by crucible sulfidation tests were also used to screen the coatings. Final evaluation of selected coatings consisted of hot corrosion rig tests at 1650F and 1800F, tensile tests at room temperature, 1400F and 1800F, stress rupture testing at 1650F and 1800F and low-cycle fatigue tests at 1400F. Modified author abstract
- Coatings, Colorants and Finishes