Copper alloy coatings manufactured by oxyfuel thermal spray onto a porcelain substrate

A coated system consisting of a ceramic substrate and a coating of a copper alloy was developed in order to provide electrically conductive properties to specific surface of the substrate. The coatings were elaborated by oxy-fuel thermal spraying processes. The best way to prepare the surface of the substrate was previously determined to achieve a sufficient adherence of copper alloy particles on the ceramic substrate. In order to manufacture the coatings an Eutectic CastolinTM 21071 powder was used, the oxy-fuel flames were produced from two different volumetric acetylene-oxygen ratios (1:1.15 and 1:2.5) obtaining a reducing and oxidizing flame respectively. The effect of surface preparation of the substrate, the coating thickness and the energy of the flame on the structure and coating adhesion were evaluated. It was found that the coatings obtained using a reducing flame presented lower adhesion values to the ceramic substrate and a higher level of porosity in its structure, while those made using an oxidizing flame presented greater adhesion and an homogenous structure (low porosity). Finally, a very low adhesion values were obtained on the non-prepared substrates with both flames.