Ion Beam Modification of Ti-Alloys

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 TiO₂,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.