微弧氧化对ZIRLO合金耐腐蚀性能的影响

Effect of Micro-Arc Oxidation on Corrosion Resistance of ZIRLO Alloy

采用磷酸盐、硅酸盐电解液体系对ZIRLO合金进行微弧氧化处理。利用XRD、SEM、TEM等研究陶瓷层的相组成、表面形貌、横截面显微组织。结果表明:在磷酸盐、硅酸盐电解液体系中制备的陶瓷层主要由m-ZrO2组成,磷酸盐电解液体系制备的陶瓷层内表面较硅酸盐电解液体系制备的陶瓷层更致密。在硅酸盐电解液体系中微弧氧化的样品靠近陶瓷层/金属界面基体一侧存在少量β-Zr。采用静态高压釜腐蚀实验研究了ZIRLO合金及D样品(磷酸盐电解液体系微弧氧化)和E样品(硅酸盐电解液体系微弧氧化)在360℃/18.6 MPa去离子水中及360℃/18.6 MPa 0.01 mol/L LiOH水溶液中的耐腐蚀性能。在360℃/18.6MPa去离子水中腐蚀至250d时,样品D和样品E耐腐蚀性能相接近,均优于未经微弧氧化处理的ZIRLO合金样品;在360℃/18.6 MPa 0.01 mol/L LiOH水溶液中腐蚀至246 d时,样品D和样品E的耐腐蚀性能与未经微弧氧化处理的ZIRLO合金样品耐腐蚀性能接近。随着腐蚀时间的延长,微弧氧化对ZIRLO合金的耐腐蚀性能提升有限。

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 ofβ-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℃/18.6 MPa deionized water and 360℃/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℃/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 d in 360℃/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.