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1148 |
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Substrate and powder preheat effects on the kinetic spray of hard metal and composite coatings on cast iron |
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Nicholas Powell / Delphi Research Labs
(Currently Dow Corning), USA N. Patel / Delphi Research Labs, USA A. A. Elmoursi*/ Delphi Research Labs, USA Z. B Zhao/ Delphi Research Labs, USA B. A. Gillispie/ Delphi Research Labs, USA B. K. Fuller/ Delphi Research Labs, USA |
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We investigate the sprayability of various hard metal and composite powder coatings via kinetic spray on a cast iron substrate by utilizing both powder and substrate preheat. This is an attempt to spray hard powders on a hard substrate. Harder particles are more difficult to spray because they require more energy to plastically deform. Therefore the hardness of the particles plays a significant role in the deposition of a coating. Similarly, harder substrates are more difficult to spray on. This work demonstrates techniques that make spraying hard particles on hard substrates possible. The coatings include copper, a copper-zirconia composite, nickel, a zinc-nickel composite, and Ti6Al4V alloy. Using the kinetic spray process [1] the coatings were applied to a cast iron substrate which was ground and sand blasted prior to spraying. Analysis performed on powders and coating includes: cross-sectional microscopy, hardness of powders and substrate, substrate temperature as a function of heating and cooling times, and adhesion at the coating/substrate level. Results include spray parameters to allow for nickel and copper coatings to be developed on cast iron, adhesion strength as a function of powder hardness, porosity of nickel and Ti6Al4V coatings, and incorporation rates of zirconia in a copper matrix on cast iron |