Environmental Resistant Coatings for High Temperature Mo Silicide Alloys
Abstract
For protective high temperature coating systems, the control of internal interfaces and interface compatibility are key factors in s"uccessful operation. Materials design for high temperature environments (T>1400~C) involves many challenges and constraints in terms" ofmelting point, chemical stability and structural functionality. In order to satisfy these constraints,multiphase microstructure"s and the capability to tune and control phase fractions and morphologies within the overall structure are required for high tempera"ture structural material performance. Besides the essential structural requirements, elevated temperatures also often involve aggres"sive environments that require a material to display an inherent oxidation and corrosion protection that can be enhanced further by" coating. In our prior work, in-situ reaction processing and kineticbiasing of reactive diffusion paths in the pack cementation syn"thesis of robust coatings on a widerange of alloy compositions in the Mo-Si-B system has been demonstrated as an effective approachto achieve stable compatibility between coating layer/substrate alloy combinations. The hightemperature protection originates from the formation of continuous aluminoborosilica on the surface and the stability and integrity of the coating is assured by incorporation of an underlying diffusion barrier. The coating performance confirms the utility of the diffusion path trajectory and kinetic bias analysis to design the layer formation and enhance the oxidation resistance. This is important since the new capability permits independent and concurrent optimization of the basealloy and the coating system. These accomplishments also allow us to address several outstanding issues in order to advance the understanding and application of coatings to the next level in the proposed continuing effort.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- May 05, 2017
- Source ID
- N000141712575
Entities
People
- John H. Perepezko
Organizations
- Office of Naval Research
- United States Navy
- University of Wisconsin System