Partial Thermal Spray Coatings for Textured Wear Surfaces
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Solution Overview
Problem
Current coating processes fail to maintain the underlying surface texture of non-smooth surfaces while providing sufficient wear resistance, and many are environmentally hazardous, such as hard chrome plating using hexavalent chromium.
Innovation Solution
A partially thermally spray coated substrate is created with discrete coated regions that maintain the underlying surface texture by applying thermal spray coatings only at specific intervals or conforming to the surface features, using techniques like high-velocity oxy-fuel or detonation gun spraying with tungsten carbide and cobalt alloys, to achieve wear resistance without degrading the surface profile.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a coating is applied to a non-smooth surface to provide wear resistance, then the wear resistance is improved, but the underlying surface texture is degraded or lost
Solution Approach 1:
The patent applies coating material selectively to specific regions of the substrate surface rather than uniformly across the entire surface. The coating is deposited in a controlled manner to cover only certain areas, allowing the surface texture to be preserved in uncoated regions while providing wear resistance where the coating is applied. This selective application resolves the contradiction by making the coating property local rather than universal.
2Reliability
If hard chrome plating is used to provide wear resistance, then the wear resistance is improved, but environmental harm is increased due to hexavalent chromium
Solution Approach 1:
The patent changes the chemical composition parameters of the coating material from traditional hexavalent chromium-based hard chrome plating to alternative materials such as metallic carbides, oxides, or other environmentally friendly compositions. This parameter change in material chemistry maintains the wear resistance function while eliminating the harmful environmental effects of Cr(VI), thus resolving the contradiction between performance and environmental safety.
3Reliability
If electrical discharge coatings are used to deposit tungsten carbide, then wear resistance is improved, but the coating coverage is insufficient resulting in poor wear resistance
Solution Approach 1:
The patent replaces the electrical discharge mechanism with a thermal spray deposition mechanism. Instead of using electrical currents to melt and deposit tungsten carbide particles, the invention uses thermal energy to heat and propel coating material particles onto the substrate surface. This substitution of the deposition mechanism enables much higher coating coverage and more uniform material distribution, resolving the contradiction between achieving adequate coating quantity and maintaining wear resistance.
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 solution effectively preserves the surface texture and provides necessary wear resistance, minimizing disruption to the surface profile while ensuring the coated regions can withstand loaded environments, thus addressing the limitations of existing coating methods.
Implementation Method 1
thermal spray coatings only at specific intervals or conforming to the surface features, using techniques like high-velocity oxy-fuel or detonation gun spraying
Implementation Method 2
high-velocity oxy-fuel or detonation gun spraying
Data Source
Figure 1a~1c
Figure 2a~3
AI summary
This invention relates to thermal spray coatings and processes onto non-smooth surfaces. The coating and processes can coat non-smooth surfaces without substantial degradation of the underlying surface texture or profile of the non-smooth surfaces so as to sufficiently preserve the underlying surface texture or profile. The ability for coating fractional coverage to maintain the surface profile while maintaining wear resistance is unprecedented by conventional thermal spray processes