钛合金的离子束改性

Ion Beam Modification of Ti Alloys

钛合金是航空航天工业常用的结构材料，它具有重量轻、强度高、抗腐蚀强等优良性能，但耐磨性较差．为提高其耐磨性，对ＴＣ４、ＴＡ７航材试件，采用溅射方法在其表面镀上钛膜，并用（Ｎ＋Ｎ＋２）混合离子束进行动态反冲注入及单元素Ｃ＋离子束注入两种方法，进行表面改性．精密摩擦、磨损试验及显微硬度测量结果，试件表面的滑动摩擦系数降低了６４％～７７％；磨损率减少了２２％～４８％；显微硬度提高０．３～１．４倍．证明离子注入有效地改善了合金表层的摩擦、磨损性能．对注入样品进行Ｘ射线光电子能谱（ＸＰＳ）分析，发现注入后的钛合金表层，生成了大量的ＴｉＯ２，并析出ＴｉＮ、ＴｉＣ等金属化合物，这是降低摩擦系数，提高耐磨性的主要因素．添加Ｃ＋离子注入的试件，其力学性能并无进一步改善，原因有待分析．

Titanium alloys are very useful in area of aeronautics and astronautics.They have good performance of light weight,high intensity and corrosion resistance,but have poor wear resistance.In order to improve their abrasion resistance,the specimens of TC4,TA7 titanium alloys were titanium plated by sputtering,and then Ti atoms were implanted into the surface of specimens by (N ++N + 2) ion beam.On the basis of the above ion implantation,some specimens were implanted by C + ion beam additionally.The results of tests of friction and wear shows that the coefficient of kinetic friction of specimens is decreased by 64%～77%,and the wear rate of specimens is decreased by 22%～48%.The measurement of microhardness show that the surface microhardness of specimens is increased by a factor of 0.3～1.4.After ion implantation,the mechanical performance are improved effectively.Analysis of X ray photoelectron spectroscopy shows that the metal compounds of TiO 2,TiN and TiC were formed in the layer of Ti alloys,which are the primary factor of decreasing the friction coefficient and increasing the wear resistance.For the specimens of additional C + ion implantation,the mechanical performance can not improve more than other,the reason will be analyzed later.