| Abstract: |
Many industrial applications, such as landing gear, compressor blades, valves and gates, require the surface properties of high hardness, superior finishing and strong adhesion to provide satisfactory wear and erosion resistance and mechanical integrity. Typically, a hardface coating is applied by thermal spray processes to meet the required property demands. In this work, an improved HVOF process is developed and investigated for applying hardface coatings with near-net-shape and ultra smooth as-sprayed surface compared to those fabricated by a conventional HVOF process. With the aid of advanced process diagnosis and evaluation tools, the effects of various process parameters were investigated on coating microstructures, surface morphologies, physical and mechanical properties. The resultant coatings demonstrate that the process will provide a smoother surface roughness, tighter and more even thickness, as well as improved erosion-resistance. By properly setting up process parameters as to tailor the coating thickness and surface morphologies, it is possible to achieve required dimension and surface roughness solely by surface finishing such as polishing or honing. This would provide a significant step forward in streamlining the manufacturing process and potentially cost.
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