Wear and corrosion of PLGA coatings on titanium in contact with bone and synovial fluid

ABSTRACT In this work, the synergism between wear and corrosion was evaluated in titanium specimens covered by PLGA. The tests were carried out in a tribocorrosion machine, taking into account two variables: scratch ve-locity and applied load. A bipotentiostat was adapted to obtain the potentiostatic curves and Tafel in resting, moving and wear-corrosion conditions. Surface topography was observed using a Carl-Zeiss Imager Z1 mi-croscope. This information, together with the results of the electrochemical tests, was used to establish the synergistic and degradation mechanisms of the material under the different test conditions. From the results obtained in this work, it was observed that the synergism is the most important factor of the degradation of the material with a percentage of 82% in such a way that the samples of titanium with PLGA coating showed wear favored by corrosion.摘要 本研究针对聚乳酸-羟基乙酸共聚物（PLGA）涂层钛试样，开展了磨损与腐蚀之间协同效应的评估工作。试验在摩擦腐蚀（tribocorrosion）试验机上开展，选取划痕速度与施加载荷两个变量作为考察参数。本研究改装双恒电位仪（bipotentiostat），以获取静止、运动及摩擦腐蚀工况下的恒电位曲线与塔菲尔（Tafel）曲线。采用卡尔·蔡司Imager Z1显微镜对试样表面形貌进行观测。结合电化学测试结果与上述观测数据，本研究阐明了不同试验工况下材料的协同效应与降解机制。本研究结果显示，协同效应是材料降解的最主要影响因素，占比达82%；带PLGA涂层的钛试样表现出腐蚀促进磨损的现象。