THE PROTECTION OF TANTALUM FROM OXIDATION AT HIGH TEMPERATURES WITH ALUMINIUM - 50% TIN COATINGS
Abstract
An Al-Sn coating was investigated as a protection against oxidation of tantalum sheet - a possilbe material for the combustion chambers of ramjets of hypersonic aircraft. Coatings containing equal parts by weight of Al and Sn were deposited from acetone slurries of the two metals and made impermeable by heating in vacuum for 1/2 hr at 1050C. The coatings which then consisted of TaAl3 covered with Al -Sn alloy, were assessed by oxidation tests, measurements of substrate hardening and mechanical tests. Tantalum was protected for up to 37 1/2 hr at 1500 C and 3 1/3 hr at 1600 C in air. Some self-healing occurred due to oxidation of molten Al -Sn alloy at defects in the outer oxide layer. Substrate hardening due to nitrogen penetration occurred in test-pieces where no signs of failure had been seen after heating in air at 1500 C. Tensile tests however showed that coated tantalum could be heated in air at 1500 C for up to 8 hr without loss of ductility at room temperature.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1966
- Accession Number
- AD0634909
Entities
People
- R. Moreton
Organizations
- Royal Aircraft Establishment