ADVANCEMENT OF PROTECTIVE COATING SYSTEMS FOR COLUMBIUM AND TANTALUM ALLOYS
Abstract
A program was conducted to study coatings for the protection of Cb and Ta base alloys. Four major areas were investigated: the basic factors associated with the formation and protection of the vacuum pack Cr-Ti-Si coating; the laboratory scale development of a spray-diffusion process for applying the Cr-Ti-Si coating; the development of metallic coatings for the protection of Cb and Ta materials at temperatures to 3500 F; and evaluation of various coating-base metal systems studied in the program. Cr-Ti-Si coatings on Cb alloys were studied in the as-formed condition and after reduced pressure and one atmosphere exposures. Electron microprobe, light and electron microscopy, and X-ray diffraction data are presented. Resulted in the laboratory scale development of a spray-diffusion process for producing Cr-Ti-Si coatings on Cb base materials are shown. Two concepts were explored in the investigation of coatings for the 2700-3500 F protection of Cb and Ta materials: alloy modification of the existing Cr-Ti-Si coating with W and Mo; and a barrier layer approach involving interposing a bonded metallic layer of W between the Cb or Ta substrate and a protective silicide coating. A property evaluation of various coating-base systems was conducted in the final phase of the program. Metallographic, oxidation and mechanical property test data are presented for various pack and slurry processed Cr-Ti-Si coatings on Cb and Ta materials. Statistical and Weibull analyses are presented.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 1965
- Accession Number
- AD0476344
Entities
People
- J. D. Gadd