Effects of nitrogen flux on microstructure and tribological properties of in-situ TiN coatings deposited on TC11 titanium alloy by electrospark deposition  

氮气流量对TC11钛合金表面电火花原位反应沉积TiN强化层显微组织和摩擦学性能的影响（英文）

作　　者：洪翔[1] 谭业发[1] 王小龙[1] 谭华[1] 徐婷[1] 

机构地区：[1]解放军理工大学野战工程学院,南京21000

出　　处：《Transactions of Nonferrous Metals Society of China》2015年第10期3329-3338,共10页中国有色金属学报（英文版）

摘　　要：In order to improve the tribological properties of titanium alloys,the in-situ TiN coatings were prepared by electrospark deposition（ESD） on the surface of TC11 titanium alloy.The effects of nitrogen flux on the microstructure and tribological properties of TiN coatings were investigated.The results show that the coating is relative thin when the nitrogen flux is small and mainly consists of Ti2N,α-Ti,Ti O and TiN phases,and the metastable phase of Ti2N is developed due to the rapid solidification of ESD.While in excessive nitrogen flux condition,many micro-cracks and holes might be generated in the coating.In moderate nitrogen flux,the coating is mainly composed of TiN phase,and is dense and uniform（50-55 μm）.The average hardness is HV0.2 1165.2,which is 3.4 times that of the TC11 substrate.The TiN coatings prepared in moderate nitrogen flux perform the best wear resistance.The wear loss of the coating is 0.4 mg,which is 2/9 that of the TC11 substrate.The main wear mechanisms of the coatings are micro-cutting wear accompanied by multi-plastic deformation wear.为提高钛合金表面耐磨性能,运用电火花沉积技术在TC11钛合金表面原位反应沉积TiN强化层,研究N2流量对强化层显微组织和摩擦学性能的影响。结果表明：当N2流量过小时,强化层厚度较薄,主要由Ti2N、α-Ti、TiO和TiN等相组成,电火花快速放电导致基体表面产生的熔池急速冷凝,使得亚稳态Ti2N相保留在强化层中;当N2流量过大时,强化层微裂纹和孔洞等缺陷较多;而当N2流量适中时,强化层主要由TiN等物相组成,且致密均匀（50~55μm）,平均显微硬度达HV0.21165.2,是TC11钛合金基体的3.4倍。当N2流量适中时,TiN强化层的耐磨性能最好,此时其磨损质量为0.4 mg,是TC11基体的2/9,其主要磨损机理为微观切削磨损和多次塑变磨损。

关 键 词：titanium alloy TiN coating electrospark deposition friction and wear 

分 类 号：TG174.4[金属学及工艺—金属表面处理]