电压对TiAl合金含ZrO2微弧氧化膜生长特性的影响

目的在TiAl合金表面制备较厚的含ZrO_2相的微弧氧化膜层,并研究电压对微弧氧化膜层生长特性的影响。方法采用可溶性锆盐电解液体系,分别在480、500、520 V电压下对TiAl合金试样进行微弧氧化处理。分别采用涡流测厚仪、扫描电子显微镜和X射线衍射仪,检测膜层的厚度、微观形貌和物相组成。结果在480、500、520 V电压下制备的膜层厚度分别为18、28、48μm,电压小幅度的增加使膜层厚度大幅度增加。膜层的主晶相为t-ZrO_2,并含有m-ZrO_2、Al2O3和Ti O2相,随着电压的升高,m-ZrO_2相的含量略有增加。膜层表面有许多大小不一的类似于"火山口"的微孔和一些陶瓷颗粒,随着电压的升高,微孔孔径增加,膜层表面粗糙度增加。结论电压对膜层相组成的影响较小,对膜层微观形貌和厚度具有显著影响。较高电压有利于提高膜层的厚度,同时会增加膜层的粗糙度和表面微孔孔径。

Effect of Voltage on Growth Characteristics of Ceramic Coating Containing ZrO2 Prepared by Microarc Oxidation on TiAl Alloy

The work aims to fabricate microarc oxide coating containing ZrO2 phase on TiAl alloy, and study effects of vol-tage on growth characteristics of microarc oxide coating. TiAl alloy samples were treated in soluble zirconate electrolyte at 480, 500 and 520 V, respectively. Eddy current thickness tester, SEM and XRD were used to observe thickness, microstructure and phase composition of the coating. Thickness of the coating prepared at 480, 500, 520 V was 18, 28, 48 μm, respectively. A small-scale increase in voltage caused a significant increase in coating thickness. Crystal phases of the coating were t-ZrO2 (primary), m-ZrO2, Al2O3, and TiO2. The content of m-ZrO2 increased slightly with the increase of voltage. Micropores and some ceramic particles of varying sizes were observed on coating surface. The pore diameter and coating roughness increased with the increase of voltage. The voltage has minor effect on phase composition of the coating and a significant impact on morphology. High voltage improves coating thickness, roughness and micropore diameter.