Effects of electrolyte constitutes on ceramic coatings of ZAlSi12Cu2Mg1 by micro-arc oxidation

ZAlSi12Cu2Mg1 samples were treated by microarc oxidation (MAO) in six different electrolytes. To obtain appropriate electrolyte constitutes, the effects of electrolyte constitutes on ceramic coatings of ZAlSi12Cu2Mg1 MAO were investigated. The results indicate that the electrolyte composition has great influence on thickness, roughness, microhardness, wear resistance, morphology and phase compositions of ceramic coating. The fine ceramic coating is obtained by changing electrolyte. The appropriate electrolyte constitutes are 8 g/L Na2SiO3, 1 g/L NaOH, 2 g/L Na2WO4, 0.5 g/L Na2EDTA and 10 mL/L glycerin. In this electrolyte, it is feasible to obtain a 156 μm thick coating, the roughness decreases to 259 nm and the microhardness increases to HV 891. The wear mass loss of coating after 30 min is only 13.29% of the matrix, which is relative to ZAlSi12Cu2Mg1 under the condition of dry friction. The morphologies of coatings are continuity and density. The XRD analysis indicates that coatings are composed of mullite, SiO2, α-Al2O3, γ-Al2O3 and WO3.