Abstract:Micro-arc oxidation (MAO) is a new technology for in-situ growth of oxide ceramic layers on valve metals( Ti, Al, Mg, Zr, Ta, etc) or their alloys. which improve the wear resistance and corrosion resistance of metals.The ZIRLO alloy was subjected to micro-arc oxidation treatment using a phosphate or silicate electrolyte system. XRD, SEM, TEM etc.were used to study the phase composition, surface morphology and cross-sectional structure of the ceramic layer. The results show that the ceramic layer prepared in the phosphate electrolyte system and the silicate electrolyte system is mainly composed of m-ZrO2. The inner surface of the ceramic layer prepared by the phosphate electrolyte system is denser than the ceramic layer prepared by the silicate electrolyte system. A small amount of β-Zr is present on the side of the substrate near the O/M interface in E sample (Micro-arc oxidation of silicate electrolyte system). ZIRLO alloy and D sample (Micro-arc oxidation of phosphorus electrolyte system) and E sample (Micro-arc oxidation of silicate electrolyte system) was studied in static autoclave at 360 °C / 18.6 MPa deionized water and 360 °C / 18.6 MPa 0.01 M LiOH aqueous solution. The corrosion weight double logarithmic curve results show that when samples corroded to 360 d in 360 °C / 18.6 MPa deionized water, the corrosion resistance of D and E samples is similar, which is better than the ZIRLO alloy sample without micro-arc oxidation; When samples corroded to 246 d in 360 °C / 18.6 MPa 0.01 M LiOH aqueous solution , the corrosion resistance of D and E samples are close to that of ZIRLO alloy samples without micro-arc oxidation treatment or even which have harmful influence on ZIRLO alloy. With the extension of corrosion time, micro-arc oxidation has limited improvement on corrosion resistance of ZIRLO alloy.