Hot Corrosion and Oxidation Studies on Cobalt-Based Alloys.
Abstract
The rates of oxidation and hot corrosion of pure cobalt, cobalt-chromium, cobalt-silicon and cobalt-chromium-silicon alloys were determined at 1000 C in oxygen at a pressure of 0.1 atmosphere. The hot corrosion studies were conducted under conditions of a continous supply of Na2S04 to the sample surface. In addition, the effect of thermal cycling on the hot corrosion resistance of the Co-15 Cr-Si alloy group was also investigated. For the cobalt-chromium alloys, it was found that a considerable decrease in the oxidation and hot corrosion rates occurred at chromium concentrations about 15 wt. %. The cobalt-silicon binary alloys showed a dramatic increase in the rate of oxidation up to 0.05 wt. % silicon according to normal doping theory. At silicon concentrations greater than 5 wt. %, a marked decrease in oxidation and hot corrosion was observed. Generally, the series of cobalt-chromium-silicon alloys exhibited much better oxidation and hot corrosion resistance than the binary alloys. The lowest rates were obtained for alloys with high silicon contents. One alloy in particular, Co-10 Cr-10 Si, exhibited the lowest total weight gain per unit area for both oxidation and hot corrosion. The hot corrosion resistances of the Co-15 Cr-Si alloys were decreased by thermal cycling. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 13, 1977
- Accession Number
- ADA053745
Entities
People
- Vincent F. Hock Jr.
Organizations
- Pennsylvania State University