Abrasive Blade Tip Coating for Oxidation Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High pressure compressor blade tips in gas turbine engines face oxidation and corrosion due to operational and environmental conditions, leading to decreased cutting performance and engine efficiency over time.
Innovation Solution
A coating system comprising abrasive grit particles on a substrate with a non-diffused matrix material and an oxidant-resistant film applied over the grit particles, which includes plated materials and concentrated alloying elements, forming a protective alloy upon exposure to high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thin film coating is applied at the blade tip over unalloyed matrix material with abrasive particles, then the abrasive coating provides cutting capability against abradable seals, but the matrix material and abrasive grit are prone to oxidation and corrosion leading to decreased cutting performance
Solution Approach 1:
The patent applies an oxidant-resistant coating (such as alumina, chromia, or other protective coatings) to the blade tip surface before the matrix material undergoes full diffusion and alloying. This preliminary protective layer prevents oxidation and corrosion of the unalloyed matrix material and abrasive grit during the period before they become self-protecting, thereby maintaining cutting performance and preventing material loss.
2Strength
If the blade tip abrasive coating is made harder and more abrasive to cut into the abradable seal, then cutting capability is improved, but the abrasive coating becomes more susceptible to oxidation and environmental degradation
Solution Approach 1:
The patent creates a composite structure where hard abrasive grit particles (such as silicon carbide, boron nitride, or other abrasive materials) are embedded in a matrix material (such as nickel-based, cobalt-based, or copper-based alloys). This composite provides both the cutting capability from the hard grit and the oxidation resistance from the protective coating system, resolving the contradiction between hardness and oxidation susceptibility.
3Productivity
If the blade tip geometry is designed to maintain minimum clearance with abradable seals, then engine efficiency is improved by reducing gas leakage, but the frequency of interaction between tips and seals increases leading to excessive wear
Solution Approach 1:
The patent modifies the surface properties of the blade tip by applying a protective coating that changes the friction and wear characteristics of the tip-seal interface. This allows the blade tip to maintain minimum clearance for high engine efficiency while the coating reduces the harmful effects of repeated interactions, thereby extending component service life and reducing excessive wear.
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 enhances oxidation resistance, maintaining cutting performance and engine efficiency by protecting the matrix material until it diffuses and forms a self-protective alloy, reducing component wear and improving durability.
Implementation Method 1
the plated material and concentrated alloying elements distributed throughout the non-diffused matrix material are configured to diffuse within the non-diffused matrix forming chromium and aluminum alloy within a diffused matrix material responsive to exposing said airfoil to an operating temperature of the turbine engine high pressure compressor
Implementation Method 2
a film of oxidant resistant coating applied over the plurality of grit particles and the non-diffused matrix material
Data Source
AI summary
An abrasive coating system for a substrate of an airfoil in a turbine engine high pressure compressor, comprising a plurality of grit particles adapted to be placed on a top surface of the substrate; a matrix material bonded to the top surface; the matrix material partially surrounds the grit particles, the matrix material consisting of unalloyed chromium and unalloyed aluminum distributed throughout the matrix material, wherein the grit particles extend above the matrix material relative to the top surface; and a film of oxidant resistant coating applied over the plurality of grit particles and the matrix material.