TC4 titanium alloy is an α+β-type two-phase titanium alloy with superior properties such as high specific strength and corrosion resistance, which is widely used in aerospace, medical and automotive fields, but the disadvantages of low hardness and lack of wear resistance are also obvious. Numerous surface modification techniques have been used to improve the wear resistance of TC4, including alloying, coating and thin film techniques. Most transition group metal carbides have the advantages of high toughness and high hardness, among which the nitrides and carbides of niobium metal are more prominent. Some scholars at home and abroad apply coating technology to the surface treatment of metal materials to improve the wear resistance of materials. For example, Roberto Mirabal-Rojas used plasma alloying technology to add Bi element in NbN coating, and the results showed that when the concentration of Bi in the produced specimen was between 4.9 and 8.4at%, the hardness was reduced to 13.9Gpa from 30GPa in NbN coating, and the coefficient of friction was reduced to 0.3 from 0.8 in NbN coating.R.M. Oliveira et al. In order to improve the high temperature and wear resistance of Nb, nitrogen ions were injected into Nb to form a modified layer of 4.5 μm, and the wear rate after treatment was reduced from 1.5 × 10-2 mm3N-1m-1 to 2.6 × 10-6 mm3N-1m-1 , while the coefficient of friction was reduced from 0.8 to 0.25, and the hardness of the specimens was significantly increased. These studies show that nitrides of metallic niobium have good wear resistance.
(1) niobium carbon nitride composite coating was successfully prepared on the surface of TC4 using double cathode sputtering deposition technology, the coating is a mixture of Nb2CN, Nb2C composition, thickness of about 10um, the surface is dense and uniform, no wrinkles breakage, the hardness of the specimen infiltrated with the coating is much higher than that of the TC4 alloy.
(2) TC4 substrate surface coated with niobium carbon nitrogen coating, the coefficient of friction fell to below 0.35, the lowest to 0.22, the wear volume from 10-4mm3N-1m-1 reduced to 10-6mm3N-1m-1 order of magnitude, the impact of the applied load is reduced, and the wear resistance is greatly enhanced.
