Tailoring of Grain Boundary Chemistry to Produce Super Creep-Resistant Alumina
Abstract
The influence of multi-valent dopants in diffusion related phenomena is complex. For situations where grain boundary diffusion predominates, factors such as grain boundary segregation and compensating defects may have countervailing influences. These are highly pertinent issues when considering the efficacy of high temperature coatings, where failure of the underlying substrate is driven by oxidation. Accordingly, the influence of impurities on the rates of both inward diffusion of oxygen, and outward cation diffusion is critical. On this note, work has initiated on simulating the distribution of a diffusing species within a medium where both rapid and slow diffusion paths exist. In practice this could be a sintered polycrystal, a thermally sprayed coating, or a fibrous composite material. Once developed, it is believed that such a model would be a valuable tool in the lifetime prediction of components, as well as the design and selection of oxidation resistant coatings.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 2003
- Accession Number
- ADA420738
Entities
People
- Helen M. Chang
- Jeffrey M. Rickman
- Martin P Harmer
Organizations
- Lehigh University