纯钛表面微弧氧化TiO2-B4C复合陶瓷膜耐磨耐蚀性研究

Wear Resistance and Corrosion Resistance of TiO2-B4C Composite Coating via Micro-arc Oxidation on Pure Ti

采用微弧氧化工艺,并掺杂B4C颗粒来制备耐磨耐蚀性优异的复合陶瓷膜,系统研究掺杂B4C含量对陶瓷膜微观形貌、物相组成、与基体结合力、显微硬度、粗糙度、耐磨性与耐蚀性的影响。结果表明:相比TiO2陶瓷膜,掺杂B4C颗粒的复合陶瓷膜更均匀致密,且由金红石型TiO2、锐钛矿型TiO2和B4C组成。随B4C浓度增大,陶瓷膜的膜层结合力、耐磨性与耐蚀性均先增强后减弱。由于具有最致密的表面形貌,TiO2-0.9B4C复合陶瓷膜的膜层结合力最大,为22.6 N。TiO2-0.9B4C复合陶瓷膜的破损时间最长,磨痕宽度最小,分别为19.24 min和384.53μm,耐磨性最好,其磨损机理为磨粒磨损与疲劳磨损。其自腐蚀电位与极化电阻最大,腐蚀电流密度最小,分别为-213.38 mV、5.47×10^4Ω·cm^2和2.37×10^-6A·.cm^2,耐蚀性最好。由Bode相图可知,陶瓷膜均由致密内层和疏松表层组成。

A composite ceramic coating containing B4 C and TiO2 with excellent wear resistance and corrosion resistance was formed on the pure Ti via micro-arc oxidation.The influence of the concentration of B4 C particles added into electrolyte on the micro structure,phase composition,adhesion,micro hardness,roughness,wear resistance and corrosion resistance of the coatings was investigated.The results show that TiO2-B4 C composite coatings consisting of rutile TiO2,anatase TiO2 and B4 C phases were more uniform and denser than TiO2 coating.With the increase in B4 C particle concentration,the adhesion,the wear resistance and corrosion resistance of the coatings increased firstly and then decreased.TiO2-0.9 B4 C coating displayed the strongest adhesion of 22.6 N due to the most compact micro structure;in addition,it also exhibited the best wear resistance.Its breakage time was 19.24 min and its wear width was 384.53μm.The wear mechanisms were abrasive wear and fatigue wear.Besides,TiO2-0.9 B4 C coating showed the best corrosion resistance.The self-corrosion potential,polarization resistance and corrosion current density of the coating were-213.38 mV,5.47×10^4Ω·cm^2 and 2.37×10^-6 A·cm-2,respectively.According to the Bode-phase diagram,it can be speculated that these coatings were composed of two oxide layers,a porous outer layer and a dense inner layer.