NiTi WIRES FOR ORTHODONTIC APPLICATION

Abstract

-In order to characterize NiTi orthodontic wires microstructure, transformation temperatures, and deformation behaviour have been investigated. Various states of dislocation density were established by additional heat treatment of a work hardened material. The as recieved wire and the change in microstructure due to the chosen heat treatment were described by optical ligth microscopy. The stress induced transformation behaviour is related with the experimental results in transformation characteristic measurements and microstructural observations.

Surface characteristics and electrochemical corrosion behavior of NiTi alloy coated with IrO2

“…The coating process mainly consists of three steps: (1) preparing the deposition solution; (2) dipping the NiTi samples into the solution prepared in step (1) for a while and then drawing them out slowly; (3) thermal oxidation of the samples prepared in step (2). Concretely speaking, for step (1), H 2 IrCl 6 ·6H 2 O was dissolved in ethanol/isopropanol (1:1) solvent, and the concentration of iridium was about 0.03 mol/L; for step (2), the samples were dipped into the H 2 IrCl 6 ·6H 2 O solution for 0.5 h at 40°C and then drew out from the deposition solution automatically by a vertical drawing machine with the drawing rate at 40 mm/min; for step (3), the wet samples were dried at a temperature of 100°C for 10 min,and then oxidized at temperature ranging from 300°C to 500°C for 1 h under air flow.…”

“…Nickel-titanium alloy, a near-equiatomic intermetallic compound, has been found widespread applications in the area of stents, dentistry, guide wires and other biomedical applications [1][2][3][4] due to its unique shape memory effect, superelasticity, as well as biocompatibility [5]. Although this marvelous shape memory alloy has acceptably biocompatibility, a limitation of the NiTi alloy is the release of Ni ions into the host body through corrosion and wear process, and Ni is believed to be toxic, allergic, and carcinogenic [6].…”