Blended Flash-Carbide Feedstock for Higher Thermal Spray Deposition
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Solution Overview
Problem
Conventional thermal spray powders exhibit low deposition efficiency and high compressive stress, leading to poor economy and inefficient coating processes, while achieving high corrosion resistance requires fine particle size and high compressive stress, which is not feasible with existing technologies.
Innovation Solution
A thermal spray material feedstock comprising a blend of two different particle types, including dense, angular first particles and spheroidal second particles, to enhance deposition efficiency and maintain coating performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional fine, dense, angular particles are used for flash-carbide coatings, then corrosion resistance is improved, but deposition efficiency deteriorates to approximately 20%
Solution Approach 1:
The patent applies composite materials by blending two distinct particle types: Type A particles (fine, dense, angular morphology with 2-10 μm size) and Type B particles (coarser, spheroidal morphology with 10-20 μm size). This composite approach allows the coating to simultaneously achieve high corrosion resistance from the fine angular particles and high deposition efficiency from the coarser spheroidal particles, resolving the contradiction between these two performance parameters.
Solution Approach 2:
The patent implements local quality by assigning different functional roles to different particle types within the coating system. Type A particles are optimized for corrosion resistance through their fine size and angular morphology, while Type B particles are optimized for deposition efficiency through their coarser size and spheroidal shape. This differentiation allows each particle type to excel at its specific function, achieving both high corrosion resistance and high deposition efficiency simultaneously.
2Reliability
If very fine particle size is used to achieve high corrosion resistance, then coating density is improved, but deposition efficiency deteriorates due to activation and peening effects
Solution Approach 1:
The patent uses Type B particles as intermediaries that facilitate the deposition process. These coarser spheroidal particles act as a mediator by providing a more efficient deposition pathway, reducing the harmful activation and peening effects that occur with fine particles alone. The Type B particles enable higher deposition efficiency while Type A particles maintain the corrosion resistance, effectively mediating between these conflicting requirements.
3Reliability
If high compressive stress is achieved through peening effect, then corrosion resistance is improved, but economy deteriorates due to material loss
Solution Approach 1:
The patent applies parameter changes by modifying the particle size distribution and morphology parameters of the feedstock. By using a bimodal distribution with Type A particles (2-10 μm) and Type B particles (10-20 μm), the coating achieves the necessary compressive stress for corrosion resistance with reduced material loss. The coarser Type B particles contribute to compressive stress without the excessive peening and material loss associated with using only very fine particles.
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 blended particle feedstock achieves deposition efficiencies up to 50% or higher, with improved coating density, wear resistance, hardness, and corrosion resistance, while controlling compressive stress and surface roughness.
Implementation Method 1
thermal spraying these conventional powders
Implementation Method 2
forms a coating composition when thermally sprayed onto a substrate surface
Implementation Method 3
remaining particles in the powder that do not form the coating activate the substrate surface and peen the coating to induce compressive stress
Data Source
AI summary
A thermal spray material feedstock is provided for “flash-carbide” coatings. Flash carbide coatings are thin, dense, and smooth thermal spray coatings that self-activate the substrate. Flash-carbide coatings form and peen the coating to impart compressive stress for good adhesion and corrosion resistance. To achieve this combination of properties and performance, a powder that includes fine, dense, and angular particles is used; however, this powder alone results in a poor deposition efficiency of typically less than 20%. The present disclosure mitigates the poor deposition efficiency of this powder alone by providing a composition having two or more different particles at a specific ratio to improve deposition efficiency with sufficient optimized stress and corrosion properties and, in some cases, an increase in coating performance.