56 / 2021-06-29 23:48:08

Corrosion behavior of hollow cathodic plasma source nitriding of additive manufacturing TC4 alloy in human body solution /空心阴极离子源渗氮增材制造TC4合金在人体溶液中的腐蚀行为研究

additive manufacturing; titanium; hollow cathode; plasma nitriding; corrosion resistance; wear resistance

Titanium alloy is widely used in aerospace, medical, energy and other fields because of its excellent comprehensive properties. Additive manufacturing titanium alloys have a low modulus of elasticity that is alternative to dense implants, while their corrosion resistance is not sufficient to meet the needs of the human environment. Hollow cathode can improve nitriding efficiency with increasing plasma density. In this paper, hollow cathodic plasma source nitriding of additive manufacturing Ti6Al4V (AM-TC4) alloy was carried out at 500℃ for 1, 3 and 5 hours. The microstructure, surface morphology, mechanical properties, corrosion resistance and wear resistance were tested by XRD, XPS, SEM, TEM, AFM, etc. Electrochemical experiment was tested with simulated body fluids. The results are as follows: With the increase of nitriding time, the peak of α-Ti phase decreases, while the peak of δ-TiN (200) and ε-Ti2N (221) increases obviously. The δ-TiN on the surface has a unique texture and fine grain, and is interlaced to form multiple twins. It is showed that the AM-TC4 alloy of nitriding for 5h has the best corrosion resistance, with the self-corrosion potential of the sample being positive 0.284V, the polarization resistance being 4.159*10⁶Ω·cm^-2, which is two orders of magnitude higher than that of the untreated sample. Corrosion resistance is greatly enhanced.