TC4表面掺La微弧氧化涂层的显微结构与耐磨性的研究

Investigation on microstructure and wear resistance of La-doped micro-arc oxidation coating on TC4 alloy surface

针对TC4钛合金在服役期间耐磨性较差等问题,本文在乙酸钙-六偏磷酸钠电解液体系下运用微弧氧化工艺在TC4钛合金表面制备出掺La陶瓷涂层。重点研究了电解液中掺杂La(NO_(3))_(3)对TC4钛合金微弧氧化涂层(MAO)耐磨性的影响。利用XRD、SEM、显微硬度计、摩擦磨损试验机、涂层附着力划痕仪等仪器对不同La(NO_(3))_(3)掺杂量下的微弧氧化涂层的物相组成、微观形貌、厚度、显微硬度、摩擦因数、结合力等指标进行表征。结果表明:随着La(NO_(3))_(3)掺杂量增加,MAO涂层由HAp、A-TiO_(2)、R-TiO_(2)、La_(2)O_(3)相组成。掺La陶瓷涂层厚度虽略有减小,但致密性有所提高。涂层的显微硬度先增大后减小、摩擦因数先减小后增大。当La(NO_(3))_(3)掺杂量为6 g/L时,涂层显微硬度提高31.18%,涂层与基体结合力提高30.59%,MAO涂层摩擦因数最小,约为0.55。

Aiming at the problem of poor wear resistance of TC4 titanium alloy during service,La-doped ceramic coatings were prepared on the surface of TC4 titanium alloy by micro-arc oxidation process in calcium acetate-sodium hexametaphosphate electrolyte system in this paper,the effect of La(NO_(3))_(3)doping in electrolyte on the wear resistance of TC4 titanium alloy micro-arc oxidation coating(MAO)was investigated.The phase composition,microstructure,thickness,microhardness,friction coefficient and adhesion of micro-arc oxidation coatings with different La(NO_(3))_(3)doping amounts were characterized by XRD,SEM,microhardness tester,friction and wear tester,coating adhesion scratch tester and other instruments.The results showed that with the increase of La(NO_(3))_(3)doping amount,the MAO coating was composed of HAp,A-TiO_(2),R-TiO_(2)and La_(2)O_(3) phases.Although the La-doped coating thickness was slightly reduced,the compactness was improved.The microhardness of the coating increased first and then decreased,at the same time,the friction coefficient decreased first and then increased.When the doping amount of La(NO_(3))_(3)was 6 g/L,the microhardness of the coating increased by 31.18%,the adhesion between the coating and the substrate increased by 30.59%.The friction coefficient of the MAO coating was the smallest,which was about 0.55.