Ion Beam Implantation and Plasma Immersion Ion Implantation. Application on Nitrided Ti-6Al-4V Titanium Alloy

Abstract

Abstract. 2014 Due to its mechanical properties and low density, the Ti-6Al-4V titanium alloy is used in hip prostheses. But the tribological behavior of Ti-6Al-4V sliding against ultra high molecular weight polyethylene involves wear degradations. The wear behavior of (Ti-6Al-4V/UHMWPE) couple can be improved by ion implantation of nitrogen. After a characterization study to find the optimal parameters for classic ion implantation, this study presents an analysis of wear behavior in comparison with chemical composition, microhardness and adhesion work for a new implantation technique, plasma immersion ion implantation.

Wear Behaviour of N Ion Implanted Ti-6Al-4V Alloy Processed by Selective Laser Melting

“…The fluence of 2 × 10 17 N + ions/cm 2 was found optimal for wear resistance associated with the formation of Ti 2 N. Higher fluences cause the formation of the harder, but less wear resistant TiN phase. It should be noted that the conditions (particularly the accelerating voltage) in Fabre et al's work [20] are different from that used in Boampong et al's [19] work (Boampong et al used Zymet Z-100 device and 100 keV voltage, while the device in Fabre et al's [20] work is Varian DF4 and the voltage is 40 keV). In addition, the authors [19,20] used UHMWPE and ion implanted or unmodified Ti-6Al-4V as wear couple in their sliding wear tests.…”

“…It should be noted that the conditions (particularly the accelerating voltage) in Fabre et al's work [20] are different from that used in Boampong et al's [19] work (Boampong et al used Zymet Z-100 device and 100 keV voltage, while the device in Fabre et al's [20] work is Varian DF4 and the voltage is 40 keV). In addition, the authors [19,20] used UHMWPE and ion implanted or unmodified Ti-6Al-4V as wear couple in their sliding wear tests. However, the material properties for ceramic or metal are quite different to polymer material, and adhesive and abrasive wear behaviours during wear tests of Ti-6Al-4V/ceramic or Ti-6Al-4V/metal should be very different from those of Ti-6Al-4V/polymer wear test [2].…”

“…Fabre et al [20] have conducted Ti-6Al-4V/UHMWPE wear testing based on a range of N + fluences at an energy of 40 keV. The fluence of 2 × 10 17 N + ions/cm 2 was found optimal for wear resistance associated with the formation of Ti 2 N. Higher fluences cause the formation of the harder, but less wear resistant TiN phase.…”

“…However, the material properties for ceramic or metal are quite different to polymer material, and adhesive and abrasive wear behaviours during wear tests of Ti-6Al-4V/ceramic or Ti-6Al-4V/metal should be very different from those of Ti-6Al-4V/polymer wear test [2]. Whether Boampong et al [19] or Fabre et al [20]'s findings could be extended to current Ti-6Al-4V sliding over a metallic counterface is uncertain. A further confusion may need to be pointed out.…”

“…In a recent overview [21] of the topic on surface modification of Ti-alloys, the condition of the dose of 1 × 10 17 N + ions/cm 2 has been referred to as the best condition, citing Rautray et al's review [18]. This dose is half the dose mentioned in [19,20] which was stated as the best N + ions dose condition. The limited studies and data reviewed above may have suggested that N ion implantation should provide wear resistance, but when a dosage of ≤2 × 10 17 N + ions/cm 2 is applied, the effect is not significant.…”