摘要
目的改善镁合金表面硬度和耐磨性能。方法采用磁控溅射法在AZ31表面制备复合Ti/TiN/TiCN涂层,在不同保温时间下对沉积后的复合涂层进行退火处理。借助X射线荧光光谱(XRF)测试复合涂层表面平均元素含量,采用X射线小角掠入射(GIXRD)技术研究涂层物相组成和残余应力,利用扫描电镜(SEM)观察涂层表面形貌和磨痕形貌,借助销盘式摩擦磨损试验机和纳米压痕仪评估涂层的耐磨性能。结果退火涂层的晶粒尺寸增加,内部缺陷减少,涂层更致密,残余应力显著下降。退火前后涂层的物相均为FCC的TiCN,不同保温时间下的涂层具有不同的择优生长取向。随着保温时间的延长,涂层表面Ti、C含量先增后减,N元素含量先减后增,涂层表面硬度下降,摩擦因数增大,耐磨性能下降。沉积涂层的韧性较好,摩擦因数波动较大,磨损机制以刮擦磨损为主。退火30 min后,涂层的磨损率最低,磨损机制以磨粒磨损和黏着磨损为主。退火90 min后,涂层的磨痕最宽,韧性最差,磨损率最高,磨损机制以磨粒磨损和氧化磨损为主。结论退火有助于降低残余应力,但退火时间不宜过长,时间超过30 min,涂层的耐磨性能下降。
This paper aims to improve the surface hardness and wear resistance of magnesium alloys.Ti/TiN/TiCN composite coatings were deposited on AZ31 by magnetron sputtering method and annealed at different holding time.The chemical composition,crystalline structure,residual stress,surface and wear morphology were determined by X-ray fluorescence(XRF),grazing incidence X-ray diffraction(GIXRD)and scanning electron microscopy(SEM),respectively.In addition,the wear resistance of the coatings was evaluated by a pin-disk friction and wear tester and a Nano indentation instrument.The results showed that the grain size of annealed coatings increased,the internal defects decreased,the coating was denser,and the residual stress decreased significantly.Moreover,the coatings were composed of FCC TiCN phase before and after annealing,which under different holding times had different preferred growth orientation.Furthermore,with the increase of the holding time,Ti and C contents on the coating surface first increase and then decrease,while N element contents first decrease and then increase,the surface hardness of the coating decreases,the friction coefficient increases,and the wear resistance decreases.The deposited coating with good toughness,the friction coefficient fluctuates greatly,and the wear mechanism is mainly scratch wear.After annealing for 30 min,the coating has the lowest wear rate,the wear mechanism is mainly abrasive and adhesive wear.After annealing for 90 min,the coating has the widest wear scratch,the worst toughness and the highest wear rate,the wear mechanism is mainly abrasive and oxidation wear.In conclusion,annealing is conducive to reducing residual stress,but the annealing time should not be too long.If the time exceeds 30 min,the wear resistance of the coating will decrease.
作者
李海涛
程东海
师超
张体明
陈宜
LI Hai-tao;CHENG Dong-hai;SHI Chao;ZHANG Ti-ming;CHEN Yi(a.College of Aviation Manufacturing Engineering,Nanchang Hangkong University,Nanchang 330063,China;College of Materials Science and Engineering,Nanchang Hangkong University,Nanchang 330063,China)
出处
《表面技术》
EI
CAS
CSCD
北大核心
2022年第7期141-149,共9页
Surface Technology
基金
南昌航空大学博士科研启动金项目(EA201903408)
国家自然科学基金青年基金(52001155)。
