Accession Number:
AD0485023
Title:
MECHANISMS OF PROTECTION AND FAILURE IN ALUMINIDE COATED TANTALUM AND TANTALUM BASE ALLOYS.
Descriptive Note:
Summary rept. Oct 64-Sep 65,
Corporate Author:
CENTRAL INST FOR INDUSTRIAL RESEARCH OSLO (NORWAY)
Personal Author(s):
Report Date:
1966-04-01
Pagination or Media Count:
51.0
Abstract:
The oxidation of tantalum and Ta-10 W with aluminumaluminide coatings and tantalum with Al-Cr coatings have been studied in the temperature range 800-1600 C and at oxygen pressures ranging from 0.1 torr to 1 atm. O2. The experimental studies comprise thermogravimetric oxidation rate measurements, x-ray diffraction studies, metallographic investigation, and electron microprobe analysis studies. The unalloyed coatings on Ta and Ta-10 W provided at 0.1 torr O2 excellent oxidation resistance at temperatures above 1100 C, but at 800-1000 C breakaway oxidation occurred. The protectivity is provided by an alpha-Al2O3 layer. At 1 atm. O2 the unalloyed coatings failed at all temperatures. The interdiffusion of aluminum and tantalum leads to the formation of TaAl3, Ta3Al, the Ta-Al phase with approximately 10 wt Al, and a Ta-Al phase with approximately 20 wt Al.
Descriptors:
- *TANTALUM ALLOYS
- *TANTALUM
- ALUMINUM COATINGS
- CORROSION RESISTANCE
- OXYGEN
- TEMPERATURE
- THERMOGRAVIMETRIC ANALYSIS
- X RAY DIFFRACTION
- TUNGSTEN ALLOYS
- PROTECTIVE TREATMENTS
- DIFFUSION
- PRODUCTION
- ALUMINUM ALLOYS
- PHASE STUDIES
- CHROMIUM
- MIXTURES
- OXIDES
- ALUMINUM COMPOUNDS
- CHROMIUM COMPOUNDS
- PROBES
- METALLOGRAPHY
Subject Categories:
- Properties of Metals and Alloys