Pulse-Plated Abrasive Coatings for Gas Turbine Blade Tips
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Solution Overview
Problem
Existing electroplated coatings for gas turbine blade tips with abrasive particles reduce fatigue life and could benefit from increased wear resistance and fatigue strengthening.
Innovation Solution
A method involving pulse plating is used to apply abrasive grit to gas turbine blade tips, utilizing a nickel or nickel-cobalt matrix with Cr-Al-Y/Hf powder, which is diffusion heat treated to form a homogenous Ni-Co-Cr-Al-Y/Hf matrix, enhancing the strength and hardness through finer grain size and reduced porosity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional electroplating is used to apply abrasive particles to gas turbine blade tips, then the coating can be applied effectively, but the fatigue life of the airfoils is reduced
Solution Approach 1:
The patent applies pulse plating with periodic on/off current cycles to deposit the coating. The current is pulsed at specific frequencies and durations, creating periodic deposition cycles that allow controlled material buildup while reducing fatigue damage accumulation compared to continuous plating
Solution Approach 2:
The patent changes multiple parameters including current density, pulse duration, duty cycle, and bath composition to optimize the coating process. These parameter adjustments enable effective coating application while controlling the microstructure to improve fatigue life
2Ease of manufacture
If conventional electroplating is used for abrasive coating, then the coating can be formed, but wear resistance and fatigue strengthening are insufficient
Solution Approach 1:
The patent creates a composite coating structure with abrasive particles (CBN, aluminum oxide, or other carbides, oxides, silicides, or nitrides) embedded in a metal matrix. This composite structure provides both the wear resistance from the abrasive particles and the fatigue strengthening from the controlled matrix microstructure
Solution Approach 2:
The patent creates local quality variations in the coating by controlling particle distribution and matrix structure at different locations and depths. The coating has enhanced hardness and wear resistance at the surface while maintaining ductility and fatigue resistance in the subsurface region
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 method increases the hardness and fatigue resistance of the coating, improving wear resistance and durability, reducing the frequency of repairs and overhauls, and allowing for faster production with improved coating uniformity and quality.
Implementation Method 1
the electrolytic application of the CBN abrasive
Implementation Method 2
which is diffusion heat treated to form a homogenous Ni-Co-Cr-Al-Y/Hf matrix
Data Source
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AI summary
A method for forming an abrasive surface includes applying an electric current through a plating solution (704) so as to cause an abrasive grit (412) to be deposited onto a workpiece (96) and varying a waveform of the electric current while building up a matrix material at least partially around the abrasive grit (412).