High Temperature Oxidation Studies on Alloys Containing Dispersed Phase Particles and Clarification of the Mechanism of Growth of SiO2.
Abstract
A relatively wide variety of oxidation tests were conducted on iron-based, cobalt-based and nickel-based alloys. Basically, these tests were conducted on alloys with various concentrations of the alloying elements chromium and /or silicon in the iron matrix with variable additions of Si3N4 particles. The Si3N4 particles dissolved to a major extent in the matrix material and also reacted with any oxygen present. Thus, the final alloy composition was iron + various levels of chromium + silicon at a number of levels + particles of unreacted Si3N4 and SiO2. Kinetic studies were made at a number of temperatures at about 1 atm of dry oxygen. It was found that the rates of oxidation were extremely slow and were comparable to many of the slowest growing commercial alloys. Nickel and cobalt based alloys were also tested with additions of Si3N4 particles and were found to behave in a manner quite similar to that of the iron based alloys described above. A small number of oxidation testss at 1000 C with P sub O2 approx. 1 atm, were also made with additions of SiA1ON, a high temperature compound found in the SI-A1-O-N system, to cobalt-chromium alloys. The oxidation behavior of Ni-Cr-SiO2 alloys has also been investigated. The final effort described in this report relates to the electrical short circuiting of SiO2 layers growing on Si(or SiC or Si3N4). Keywords: Thermogravimetric Analysis; Microscopy.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 28, 1986
- Accession Number
- ADA173210
Entities
People
- G. Simkovich
Organizations
- Pennsylvania State University