Fretting Wear of NiTi - Shape-Memory Alloy

This study presents the results of tests of friction processes and fretting wear of NiTi shape-memory alloy, which is used in orthodontics and surgery. This research problem is significant because nickel ions released as a result of nitinol wear exhibit toxic action in the human body. Knowledge about wear mechanisms will allow for more effective prevention of processes leading to the destruction of elements of medical constructions and extend the time of their safe operation. Tests were performed on a pin-on-disc fretting tester under dry friction conditions and in a simulated oral cavity environment. Wear assessments were conducted on the basis of microscopy (SEM, TEM, CLM). Obtained results indicate that friction conditions have a significant impact on the mechanism of fretting wear, which is primarily related to oxidation and phase transformation of nitinol.