Accession Number : AD0843588

Title :   Coatings for Long Term-Intermediate Temperature Protection of Columbium Alloys.

Descriptive Note : Technical rept. 1 Jul 66-31 Apr 68,

Corporate Author : TRW EQUIPMENT LABS CLEVELAND OH

Personal Author(s) : Nejedlik, J. F. ; Gadd, J. D.

Report Date : OCT 1968

Pagination or Media Count : 263

Abstract : The program objective was to develope protective coatings for columbium alloys that would provide hundreds of hours of protection at temperatures to 2500deg F for application in gas turbine engines and aerospace environments. The coating systems under consideration were basically silicides and aluminides, with improvements to be achieved by modification with elements such as V, Al, Mo, Cr and Ti. Specifically, a ductile coating was sought that would improve upon the Cr-Ti-Si coating system, the standard of comparison for this program. The V-CrTi-Si system was extensively evaluated on various columbium alloy substrates. It exhibited a potential for 1000 hours of protection at 1000-3200deg F in cyclic oxidation tests and over 200 hours at 2400deg F. In oxidation-erosion rig tests the coating system protected various columbium alloy substrates for up to 200 hours at 2200deg F and 100 hours at 2400deg F. The V-CrTi-Si system was superior to the CrTi-Si system only in cyclic oxidation tests. In other tests, such as oxidation-erosion, ballistic impact, and slow thermal cyclic exposure, the two systems performed similarly. (Author, modified-PL).

Descriptors :   (*GAS TURBINES, NIOBIUM ALLOYS), (*NIOBIUM ALLOYS, THERMAL STRESSES), (*COATINGS, CORROSION INHIBITION), DIFFUSION COATING, SILICON COATINGS, SLURRY COATING, SILICIDES, DEPOSITION, ALUMINUM COATINGS, ADDITIVES, VANADIUM, CHROMIUM, TITANIUM, MOLYBDENUM, GAS TURBINES.

Subject Categories : Coatings, Colorants and Finishes
      Fabrication Metallurgy
      Jet and Gas Turbine Engines

Distribution Statement : APPROVED FOR PUBLIC RELEASE