WEAR CHARACTERIZATION OF BIOMEDICAL POROUS ALLOY (Ni_50–xTi₅₀Cu_x) AT ELEVATED TEMPERATURE

Abstract

In today’s scenario a small amount of wear can change the dimensions of devices, especially in micro-devices. Equiatomic NiTi alloy has its applications in engineering and medical due to shape memory, pseudoelasticity, biocompatibility and corrosion resistance. In the present research copper is mixed at different proportion from 0 to 10% in NiTi alloy to study the wear behavior and its mechanism at different loads and temperature environments (37 to 250 °C). The wear results (WC/Ni_50–xTi₅₀Cu_x couple) show that the wear rate increases with increasing load and temperature. After a certain temperature the wear rate decreases due to formation of mechanically mixed layer. Microhardness of NiTi alloy also increases after increasing copper contents. X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS) and scanning electron microscopy (SEM) techniques were used to check the phases of wear pins and WC disk. Ni₄₀Ti₅₀Cu₁₀ pin was suggested for the biomedical application due to its low wear rate; the same surface was evaluated at different load to study the wear mechanisms. Defragmented particles were studied to investigate the morphology of debris at differ-ent loads. XRD analysis reveals that with the addition of copper content in NiTi alloy, the wear resistance increases due to intermediate phase TiNi_0.8Cu_0.2 matrix.