Wear-Resistant Coating for Turbomachinery Blade Tips
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Solution Overview
Problem
Turbomachinery blade tips experience rapid depletion of abrasive coatings due to high radial interaction rates during engine operations like bird strikes and engine surges, leading to increased gas leakage and reduced efficiency, while low interaction rates cause excessive wear and damage to abradable seals.
Innovation Solution
A wear-resistant coating comprising a substrate with an abrasive coating and a layer of material such as titanium nitride, boron nitride, or aluminum oxide is applied to the blade tips, where the abrasive coating includes cubic boron nitride or silicon carbide particles dispersed in a matrix, and the layer of material is deposited using physical vapor deposition to enhance abrasion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the blade tip abrasive coating is used to maintain cutting capability during high radial interaction rates (e.g., bird strike, engine surge), then the blade tip can effectively abrade the abradable seal, but the abrasive coating depletes rapidly leading to unwanted sliding contact of base material
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition and microstructure of the blade tip coating through controlled alloying elements and heat treatment processes. This transforms the coating properties to achieve both high radial interaction capability and extended service life by optimizing the balance between abrasiveness and wear resistance
Solution Approach 2:
The patent employs composite materials by creating a multi-phase coating system that combines abrasive particles embedded in a metallurgical matrix. This composite structure allows the coating to maintain cutting capability through the abrasive phase while the matrix phase provides structural integrity and resistance to rapid depletion during high-speed interaction with abradable seals
2Stability of the object's composition
If the blade tip abrasive coating is used during low radial interaction rates (e.g., green run), then the coating can maintain its structure, but excessive wear and damage occurs to the abradable seal due to large thermal excursions
Solution Approach 1:
The patent applies parameter changes by modifying the thermal conductivity and specific heat capacity of the coating through compositional adjustments. This transforms the thermal response characteristics to reduce thermal excursions during low-speed operation, protecting the abradable seal from excessive heat while maintaining coating structural stability
Solution Approach 2:
The patent employs local quality by creating zones within the coating with different thermal and mechanical properties. The coating structure is optimized to have regions that can absorb thermal energy during low-speed operation, preventing excessive heat transfer to the abradable seal while maintaining overall coating integrity
3Loss of substance
If the abrasive coating is depleted, then the blade tip base material (titanium, nickel, steel, aluminum alloys) contacts the abradable seal directly, but this causes unwanted sliding contact, excessive seal wear, and increased gas leakage
Solution Approach 1:
The patent applies parameter changes by optimizing the coating thickness, composition, and microstructure to achieve enhanced wear resistance. This transforms the coating's ability to resist depletion, ensuring it maintains protective function throughout the intended service life and prevents direct contact between base material and abradable seal
Solution Approach 2:
The patent employs composite materials by designing a coating system where abrasive particles are strongly bonded within a metallurgical matrix. This composite structure prevents grain pull-out and coating depletion, maintaining a protective barrier that prevents direct sliding contact between the blade tip base material and abradable seal, thereby ensuring reliable engine operation
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 significantly reduces degradation and enhances abrasion resistance, preventing grain pull-out and maintaining the cutting capability of blade tips over multiple operating cycles, thereby minimizing gas leakage and maintaining engine efficiency.
Implementation Method 1
the layer of material is deposited using physical vapor deposition to enhance abrasion resistance
Data Source
AI summary
Disclosed herein is an article comprising a substrate; an abrasive coating disposed on the substrate; where the abrasive coating comprises a matrix having abrasive grit particles dispersed therein; and a layer of material disposed on the abrasive coating; where the layer of material is a titanium nitride (TiN), boron nitride (BN), titanium-aluminum-nitrides [(TiAl)N], titanium-aluminum-silicon-nitrides [(TiAlSi)N], chromium nitrides (CrN), aluminum oxide (Al2O3), titanium oxide (TiO2), silicon carbo-nitride (SiCN), titanium carbo-nitride (TiCN), or a combination thereof.