Preliminary Study of Methods for Providing Thermal Shock Resistance to Plasma-Sprayed Ceramic Gas-Path Seals.
Abstract
The cyclic thermal shock resistance of several outer air, gas-path seal systems for high-pressure turbines was evaluated. In all these systems, plasma-sprayed, yttria-stabilized zirconium dioxide was the ceramic constituent. The most promising approaches were those that had a porous-metal, low-modulus pad as a strain isolator between the ceramic layer and the dense metal substrate. Cooling pins extending into the low-modulus pad significantly reduced the oxidation rate of the porous metal and the extended seal life. The thermal shock resistance of the ceramic layer was improved by increasing its porosity and by precracking it before thermal shock testing. Microstructural and probe studies suggested that the long-term durability of the high-pressure-turbine seal systems would be adversely affected if the metal-ceramic interfaces exceeded about 800 C because some metallic species would rapidly diffuse. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1980
- Accession Number
- ADA084325
Entities
People
- David E. Brewe
- Donald W. Wisander
- Robert C. Bill
Organizations
- National Aeronautics and Space Administration