Compressor Seal-Ring Coating for High-Temperature Wear Resistance
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Solution Overview
Problem
Existing high-pressure compressor seal-ring assemblies in gas turbine engines experience premature failure due to poor tribological behavior of nickel superalloys under high temperature and vibratory conditions, leading to excessive wear and costly damage to critical components.
Innovation Solution
A compressor seal-ring assembly featuring a nickel, cobalt, or iron-based superalloy seal with a CoCrAlY-containing lubricant coating, and optionally an additional hBN-based lubricant coating on the counterface, which reduces friction and wear through a Co—Co interface and low-friction sliding regime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If nickel superalloy seal rings are used under high temperature and vibratory conditions, then the seal can operate in harsh environments, but the tribological behavior deteriorates leading to premature wear failure
Solution Approach 1:
The invention applies a composite coating system consisting of a CoCrAlY-based thermal barrier coating combined with a solid lubricant coating (such as hBN or MoS2) on the seal ring surface. This composite structure combines the high temperature resistance of the superalloy substrate with the low friction and wear properties of the lubricant coating, resolving the contradiction between temperature endurance and wear resistance
Solution Approach 2:
The invention changes the surface properties of the seal ring by applying coatings with different physical and chemical parameters than the base material. The CoCrAlY coating provides oxidation resistance and thermal barrier properties, while the solid lubricant coating provides low coefficient of friction, thereby improving tribological behavior without compromising high temperature operation
2Ease of manufacture
If existing seal ring materials are used, then manufacturing is straightforward, but the seal requires constant replacement due to excessive wear
Solution Approach 1:
The invention applies lubricant coatings to the seal ring surface before the seal is installed and put into service. This preliminary action of coating the surface with low-friction material ensures that the seal starts operation with optimized tribological properties, extending service life without complicating the manufacturing process significantly
Solution Approach 2:
The solid lubricant coating acts as an intermediary layer between the seal ring and the counterface (IBR surface). This intermediate layer reduces direct contact and friction between the metal surfaces, thereby extending seal life while maintaining ease of manufacture of the individual components
3Ease of operation
If nickel superalloy seal rings operate under high vibratory energy conditions, then the seal can function in dynamic environments, but the counterface suffers costly damage due to poor tribological behavior
Solution Approach 1:
The invention converts the high vibratory energy conditions that cause harmful fretting wear into beneficial self-lubrication effects. The solid lubricant coating materials (such as hBN or MoS2) have layered structures that facilitate easy shear under vibratory conditions, transforming the harmful vibration-induced wear into a low-friction sliding regime that protects the counterface
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The lubricant coating system significantly reduces wear on both the seal and the counterface, extending the life of engine components and minimizing overhaul costs by creating a low-friction environment that withstands high vibratory energy and temperature exposure.
Implementation Method 1
a lubricant coating on the seal, the lubricant coating comprising a CoCrAlY-containing material
Implementation Method 2
moving the counterface relative to the seal to deposit a transfer coating from the lubricant coating on the counterface
Data Source
AI summary
A compressor seal-ring assembly includes a seal formed of a nickel, cobalt or iron-based superalloy; a counterface positioned for sealing interaction with the seal; and a lubricant coating on the seal, the lubricant coating being formed of a CoCrAlY-containing material.