Effect Of Micro-Arc Oxidation On Corrosion Resistance Of Zirlo Alloy

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 beta-Zr is presented on the side of the substrate near the O/M interface in E sample (micro-arc oxidation in silicate electrolyte system). ZIRLO alloy and D (micro-arc oxidation in phosphorus electrolyte system) and E samples (micro-arc oxidation in silicate electrolyte system) were studied in static autoclave at 360 degrees C/18.6 MPa deionized water and 360 degrees C/18.6 MPa 0.01 mol/L LiOH aqueous solution. The corrosion weight gain double logarithmic curve results show that when samples are corroded to 250 d in 360 degrees C/18.6 MPa deionized water, the corrosion resistance of D and E samples is similar, which is better than that of the ZIRLO alloy sample without micro-arc oxidation; When samples are corroded to 246 din 360 degrees C/18.6 MPa 0.01 mol/L 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 it has harmful influence on ZIRLO alloy. With the extension of corrosion time, micro-arc oxidation has limited improvement on corrosion resistance of ZIRLO alloy.