Sliding Component Coating for High-Temperature Wear and Oxidation
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Solution Overview
Problem
Conventional wear-resistant coatings on sliding components, such as those in gas turbines, degrade at high temperatures exceeding 1000°C due to oxide coating spallation, leading to reduced oxidation and wear resistance.
Innovation Solution
A wear-resistant coating system for sliding components, comprising a Ni alloy with an Al-containing Co alloy layer on the surface and a Co alloy layer on the substrate, including a CoAl phase and an intermediate layer, with specific Al and Cr oxide layers formed through a cladding and Al diffusion coating process, enhancing oxidation and wear resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a Co-based alloy wear-resistant coating is used on sliding components, then wear resistance is improved, but oxidation resistance deteriorates at high temperatures exceeding 1000°C due to oxide coating spallation
Solution Approach 1:
The invention applies a composite coating structure consisting of a Co-based alloy layer (providing wear resistance) and an Al-containing layer (providing oxidation resistance). This multi-layer composite structure allows the sliding component to simultaneously achieve excellent wear resistance from the Co-based alloy and oxidation resistance from the Al-containing protective layer, even at high temperatures exceeding 1000°C
Solution Approach 2:
The invention creates different chemical compositions and properties at different depths of the coating. The surface layer contains high Al content (0.3-26% by mass) to form protective oxide scales for oxidation resistance, while the underlying Co-based alloy layer provides wear resistance. This local differentiation of material properties resolves the contradiction between wear resistance and oxidation resistance
2Reliability
If Al content in the Co-based alloy is increased to improve oxidation resistance, then oxidation resistance is improved, but the alloy structure and wear resistance properties may deteriorate
Solution Approach 1:
The invention optimizes the Al content parameter within a specific range (0.3-26% by mass) to achieve the desired balance between oxidation resistance and alloy structure stability. This controlled parameter change ensures that sufficient Al is present to form protective oxide scales while preventing excessive Al that would compromise the Co-based alloy structure and wear resistance properties
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 coating system provides excellent oxidation resistance and wear resistance even at high temperatures, preventing oxide coating detachment and maintaining performance in extreme environments.
Implementation Method 1
the first oxide layer that is formed on a surface of the Al-containing Co alloy layer and includes an Al oxide
Implementation Method 2
the first oxide layer that is formed on a surface of the Al-containing Co alloy layer and includes an Al oxide and a Cr oxide
Implementation Method 3
an Al diffusion coating step for subjecting the sliding component on which the cladding layer is formed to an Al diffusion coating to set an Al content at least on a surface side of the cladding layer
Data Source
AI summary
A sliding component having a wear-resistant coating includes a sliding component formed of a Ni alloy, and a wear-resistant coating provided on a sliding surface of the sliding component. The wear-resistant coating has, at least on the surface side thereof, an Al-containing Co alloy layer which contains Co as a main component, at least one of W, Ni, Mo, Fe, Si, and C, Cr, and 0.3% by mass or more and 26% by mass or less of Al.