To improve the fracture mechanical property of the brittle biological coating prepared by micro-arc oxidation(MAO)on the Ti-13Nb-13Zr alloy surface,a combined technique of ultrasonication and micro-arc oxidation(US+MAO)was used to fabricate Ca-P biological coating.Indentation test was adopted to analyze coating fracture toughness,and scanning electron microscopy(SEM)and X-ray diffraction(XRD)were employed to determine coating surface morphology and phase composition.Moreover,the coating performance was compared with that prepared by the original MAO process,and the toughening factors were analyzed.The results show that all the US+MAO coatings have higher fracture toughness compared with coatings prepared by the ori-ginal MAO process under the same duty cycle.Phase transformation toughening of partial rutile TiO2 to anatase,coating densification and thickening induced by ultrasonic cavitation effect,and the well distributed micro-cracking are the main causes that lead to enhanced fracture mechanical property.This combined technique achieves the toughening of MAO titanium alloy biological coating.%为了提高微弧氧化钛合金制备的脆性仿生涂层的断裂力学性能,利用超声辅助微弧氧化复合工艺在Ti-13Nb-13Zr合金表面制备了钙磷生物涂层.通过压痕法测试分析了涂层断裂韧性,采用扫描电镜和X射线衍射仪测试了涂层表面形貌和相组成,并与微弧氧化制备的涂层性能进行了比较,分析了增韧原因.结果表明,引入超声后,微弧放电电压下降了40 V,涂层致密层明显增厚;相同电源占空比条件下,超声工艺所制备涂层的断裂韧性相比无超声工艺都有所提高.部分锐钛矿相TiO2转变为金红石相的相变增韧,超声空化效应引起的涂层致密化和增厚效果,以及微裂纹的均匀分布,是促使涂层断裂力学性能提高的主要原因.该复合工艺实现了微弧氧化钛合金生物涂层的增韧.
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