钛合金表面微弧氧化涂层理化性能及表面形貌研究

Physicochemical properties and surface topography of micro-arc oxidation coating on titanium alloy surface

目的研究Ti．6A1—4V合金表面微弧氧化（MAO）涂层的表面形貌及理化性能。方法将Ti-6A1-4V合金置于含0．02mol／Lβ-甘油磷酸二钠盐及0．2mol／L乙酸钙的电解液中进行MAO处理后，通过扫描电子显微镜（SEM）观察涂层表面形貌及截面形貌；X线能谱分析（EDX）检测涂层表面钙磷比；X射线衍射分析（XRD）检测涂层晶相构成；纳米压痕试验测量涂层的微弹性模量及微硬度。结果经MAO处理后，钛合金表面形成粗糙多孔的氧化膜；XRD显示涂层主要由锐钛矿相TiO2、金红石相Ti02和羟基磷灰石（HAP）构成；EDX及纳米压痕试验测得膜层的钙磷比为1．64，弹性模量和微硬度分别为（32．07±7．07）GPa和（1．49±0．68）GPa。结论通过MAO技术可制备出具备良好理化性能的含HAP的涂层。

Objective To explore the surface topography and physicochemical properties of the coating formed by micro-arc oxidation （MAO） technique on Ti-6A1-4V alloy. Methods The surface of Ti- 6AI-4V specimens was treated with MAO technique by using electrolytes containing 0.02 mol/L sodium β- glycerophosphate and 0.2 mol/L calcium acetate. This was followed by scanning electron microscopic examination of the surface and cross- sectional morphology of MAO coating, and energy dispersive spectroscopic examination for capturing the surface calcium- to- phosphorous ratio. The crystal phase of coating was analyzed by X-ray diffraction, and atomic force microscopy was employed to measure the micro hardness and elastic modulus. Results The rough and porous oxidation layer formed on the surface of MAO- treated titanium alloy, based on X-ray diffraction assessment, consisted mostly of anastase- and rutile-phase titanium dioxide and hydroxyapatite, with a calcium-to-phosphorous ratio of 1.64： 1, as reflected by energy dispersive spectroscopy and atomic force microscopy. The model also yielded an elastic modulus and micro- hardness of （32.07±7.07）GPa and （1.49±0.68）GPa, respectively. Conclusion Surface coating containing hydroxyapatite featured by favorable property and surface topography may be achieved by MAO technique.