Characterization of Tin Bronze Substrates Coated by Ag + B83 through Electro-Spark Deposition Method

— The composite coatings on the surface of tin bronze substrates were formed by electro-spark deposition applying alternately the soft materials of silver and the alloy Babbitt B83. The effect of their deposition on the mass transfer, the surface roughness, the coating thickness, the surface morphology, the cross-sectional morphology, the elemental composition, and the tribological properties of the composite coatings was investigated using electronic scales, a 3D optical profilometer, a tribometer, and such techniques as scanning electron microscopy, and energy dispersion spectroscopy. The results show that the studied composite coatings were dense, with grains refined and uniformly distributed, and they functioned via the metallurgical fusion with the substrate. The silver and Babbitt B83 optimal process parameters were obtained as follows: the voltage of 60 and 30 V, the duty cycle of 30 and 30%, and the efficiency of 1 and 3 min/cm 2 , respectively. Under the optimal process parameters, the mass transfer was 125.2 mg, the surface roughness of the composite coatings was 19.43 μm, and the maximal thickness of the layers was 80 μm. The minimum friction coefficient of the composite coatings was about 0.177 after the running-in stage. The main wear mechanisms of the composite coatings prepared under the optimal process parameters were plastic deformation and abrasive wear accompanied by slight polishing.