Corrosion Behavior of Nitrided Layer of Ti6Al4V Titanium Alloy by Hollow Cathodic Plasma Source Nitriding

Abstract

Ti6Al4V titanium alloys, with high specific strength and good biological compatibility with the human body, are ideal materials for medical surgical implants. However, Ti6Al4V titanium alloys are prone to corrosion in the human environment, which affects the service life of implants and harms human health. In this work, hollow cathode plasm source nitriding (HCPSN) was used to generate nitrided layers on the surfaces of Ti6Al4V titanium alloys to improve their corrosion resistance. Ti6Al4V titanium alloys were nitrided in NH3 at 510 °C for 0, 1, 2, and 4 h. The microstructure and phase composition of the Ti-N nitriding layer was characterized by high-resolution transmission electron microscopy, atomic force microscopy, scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. This modified layer was identified to be composed of TiN, Ti2N, and α-Ti (N) phase. To study the corrosion properties of different phases, the nitriding 4 h samples were mechanically ground and polished to obtain the various surfaces of Ti2N and α-Ti (N) phases. The potentiodynamic polarization and electrochemical impedance measurements were conducted in Hank’s solution to characterize the corrosion resistance of Ti-N nitriding layers in the human environment. The relationship between corrosion resistance and the microstructure of the Ti-N nitriding layer was discussed. The new Ti-N nitriding layer that can improve corrosion resistance provides a broader prospect for applying Ti6Al4V titanium alloy in the medical field.

Tribocorrosion and Surface Protection Technology of Titanium Alloys: A Review

“…The chemical surface heat treatment methods mainly include nitriding, carburizing, oxidating, and boronizing. Nitriding treatment is the most commonly used chemical heat treatment method for titanium metal surfaces, including gas nitriding, plasma nitriding, and laser nitriding [ 183 , 184 , 185 , 186 , 187 , 188 , 189 , 190 , 191 , 192 ]. The nitriding temperature of titanium metal is much higher than that of steel materials.…”

Low Temperature Nitriding of Metal Alloys for Surface Mechanical Performance

“…Still, improvements and prospects are expected in the near future, with an observed large activity in the field [ 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 ]. Overall, a more detailed picture of the complex nitriding process could be obtained.…”

Effect of trace oxygen on plasma nitriding of titanium foil

“…Plasma nitriding technology has been widely used in industrial and medical areas to improve the poor tribological properties of titanium alloy. [1][2][3][4][5][6][7][8] One study by Tarnowski et al discussed that the nitride layer presented many advantages such as low coefficient of friction, low penetration depth and good adhesion to the matrix. [1] The investigation by Yilbas et al showed that TiN/Ti 2 N layers were formed after nitriding treatment and the wear resistance was considerably increased via pin-on-disc wear test.…”