Microarc oxidation coatings formed on Ti6Al4V in Na2SiO3 system solution: Microstructure, mechanical and tribological properties
Microarc oxidation coatings formed on Ti6Al4V in Na2SiO3 system solution: Microstructure, mechanical and tribological properties
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DOI：
10.1016/j.surfcoat.2005.10.044
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发表时间：
2006-09
影响因子：
5.4
通讯作者：
Yuhang Wang;B. Jiang;T. Lei;L. X. Guo
中科院分区：
文献类型：
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作者：
Yuhang Wang;B. Jiang;T. Lei;L. X. Guo
采用脉冲双极电源，在na2sio3体系溶液中进行微弧氧化，在Ti6Al4V合金表面形成陶瓷涂层。采用扫描电镜（SEM）、x射线衍射（XRD）和x射线光电子能谱（XPS）对陶瓷涂层的微观结构、物相和元素组成进行了表征。通过纳米压痕和剪切试验分别测定了涂层的力学性能分布和粘接强度。使用销盘式磨损试验机评估了其摩擦学性能。结果表明：该涂层主要由金红石和少量锐钛矿TiO2组成，并掺入了电解质组分中的无定形化合物；涂层致密区的硬度和弹性模量分别为8.5 GPa和87.4 GPa，基体的硬度和弹性模量分别为4 GPa和150 GPa。硬度和弹性模量沿厚度约为45 μm的涂层呈现相似的分布规律，致密区硬度和弹性模量基本保持不变，最终下降到基体疏松区硬度和弹性模量以下。粘接强度约为70 MPa。在<1 N载荷和<2500滑动循环时，涂层与钢的摩擦系数低至0.2-0.3。然而，在磨损试验后期发生的氧化磨损机制导致摩擦系数逐渐增大。
Ceramic coatings were formed on the surface of Ti6Al4V alloy by microarc oxidation (MAO) in a Na2SiO3system solution using a pulsed bipolar power supply. The microstructure, phase and elemental composition of the ceramic coatings were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The distribution of mechanical properties across the coating and its adhesion strength were determined by a nanoindentation and a shear test respectively. The tribological properties were evaluated using a pin-on-disk wear tester. The results show that the coatings are mainly composed of rutile and a small amount of anatase TiO2, with amorphous compounds from electrolyte components incorporated. The hardness and elastic modulus are about 8.5 GPa and 87.4 GPa for the compact region of the coating, and about 4 GPa and 150 GPa for the substrate. Similar profiles of hardness and elastic modulus along the coating of about 45 μm thickness is found, and both values in the compact region remain mainly constant before finally declining to below those of the substrate in the outer loose region. The adhesion strength is about 70 MPa. The friction coefficient of the coating against steel is as low as 0.2–0.3 at <1 N load and at <2500 sliding cycles. However, the oxidation wear mechanism occurring at the later stage of wear tests leads to a gradual increase of friction coefficient.