HIGH-TEMPERATURE OXIDATION-RESISTANT COATINGS FOR TANTALUM BASE ALLOYS

Technical Report · Tue Jan 01 04:00:00 EST 1963

OSTI ID:4718266

Sama, L

The effect of coating composition on structural changes and oxidation behavior was studied using a Sn-Al sprayslurry system with Ta, Ta alloys, Nb, W, and Mo. In tests conducted at 3000 un. Concent 85% F it was found that increased oxidation protection was most significantly related to the thickness of the Sn-rich phase at the surface. The use of refractory metal powder additives plus excess Al to form aluminide particles served best to increase the thickness of the phase. Coating composition was optimized and an extensive evaluation was carried out with Ta- 10% W, Ta-30% Nb-7.5% V, and Nb-5% Zr. In oxidation tests at 1100 to over 3000 un. Concent 85% F protective life was significantly affected by substrate composition, coating thickness, and thermal cycling. Tensile and stress rupture data were obtained on coated samples at 2000 to 3000 un. Concent 85% F and correlated fairly well with data for uncoated material. Preliminary studies were made of coating stability at air pressures in the micron to millimeter range. Oxidation and diffusion effects were explored by metallographic electron probe and x-ray analysis. A brief study of Ta-10Hf-5W in contact with Al/sub 2/O/sub 3/ at elevated temperatures showed that the alloy was unstable in contrast to pure Ta, Ta-10W, and Ta-30Nb-7.5V, which were quite stable. Oxidation data were obtained for several Ta alloys coated with Ti-Si. A diluent system was sought for beryllide-type coatings in which Sn, Cu, Si, and Ag were investigated. The use of Ag as a slurry base was found to be most promising. (auth)

• Research Organization: General Telephone and Electronics Labs., Inc., Bayside, N.Y.
• NSA Number: NSA-17-022109
• OSTI ID: 4718266
• Report Number(s): ASD-TDR-63-160
• Country of Publication: United States
• Language: English

Related Subjects

AIR
ALUMINUM ALLOYS
ALUMINUM OXIDES
BERYLLIUM ALLOYS
COATING
COPPER ALLOYS
CORROSION PROTECTION
DIFFRACTION
DIFFUSION
ELECTRON BEAMS
HAFNIUM ALLOYS
HIGH TEMPERATURE
METALLOGRAPHY
METALS, CERAMICS, AND OTHER MATERIALS
NIOBIUM ALLOYS
OXIDATION
POWDERS
PRESSURE
SILICIDES
SILVER ALLOYS
SLURRIES
SPUTTERING
STABILITY
STRESSES
SURFACES
TANTALUM ALLOYS
TEMPERATURE
TENSILE PROPERTIES
THICKNESS
TIN ALLOYS
TITANIUM ALLOYS
TUNGSTEN ALLOYS
VANADIUM ALLOYS
X RADIATION
ZIRCONIUM ALLOYS