Hard Phaseless Metallic Coating for Compressor Blade Tip Wear
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Solution Overview
Problem
Existing gas turbine engines face challenges in maintaining a tight seal between compressor blades and the casing due to wear issues at high temperatures, particularly when using abrasive and abradable materials, which leads to reduced operational lifetime and efficiency.
Innovation Solution
A hard phaseless metallic coating, primarily composed of at least 99.5% molybdenum, is applied to the blade tips to provide strength and reduce wear, ensuring the blade tip remains stronger than the abradable material at all operating temperatures, thereby forming a durable seal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If abrasive material is used on blade tip to form seal with abradable material on casing, then seal tightness is improved, but wear resistance and operational lifetime are reduced due to high temperature wear
Solution Approach 1:
The patent applies a hard phaseless metallic coating (at least 99.5% molybdenum) to the blade tip, fundamentally changing the material parameters of the sealing surface. This coating maintains strength and wear resistance at high temperatures where conventional abrasive materials fail, thereby extending operational lifetime while preserving seal tightness through the coating's inherent hardness and thermal stability
Solution Approach 2:
The invention creates a composite structure by applying a hard phaseless metallic coating layer over the blade tip base material. This composite approach combines the wear resistance and high-temperature strength of the molybdenum coating with the structural properties of the underlying blade material, achieving both durable sealing and extended service life under thermal loading
2Reliability
If conventional abrasive coating is applied to blade tip, then sealing function is achieved, but wear resistance at high temperatures deteriorates
Solution Approach 1:
The patent fundamentally changes the material parameters by using hard phaseless metallic coating (≥99.5% molybdenum) instead of conventional abrasive materials. This coating maintains its strength and wear resistance properties at high operating temperatures, preventing the degradation that occurs with traditional abrasive coatings while preserving the sealing function through controlled interaction with the abradable casing material
3Reliability
If abrasive material rubs against abradable material during rotation, then tight seal is formed, but blade tip wear increases reducing operational lifetime
Solution Approach 1:
The hard phaseless metallic coating changes the tribological parameters of the blade tip surface. The coating's exceptional wear resistance and thermal stability reduce the rate of material loss during rotation against the abradable casing material, thereby maintaining seal tightness while significantly reducing blade tip wear and extending operational lifetime
Data Source
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AI summary
A blade includes an airfoil having pressure and suction side walls extending in a spanwise direction from a blade root to a blade tip and a hard phaseless metallic coating located at the blade tip. An assembly includes a casing having an inner diameter surface, an abradable coating located on a portion of the inner diameter surface, a blade having a blade tip configured to rotate within the casing where the blade tip and the inner diameter surface of the casing form a seal, and a hard phaseless metallic coating located on the blade tip. A method of making a blade includes forming a blade having a tip and depositing a hard phaseless metallic coating on the blade tip.