SURFACE TREATMENT OF NI-TI SHAPE MEMORY ALLOY IMPLANT FOR IN-VIVO IMPLANTATION

摘要

PURPOSE:To greatly improve the adaptability to the living body by subjecting the implant for in-vivo implantation consisting of an Ni-Ti shape memory alloy to a surface treatment with an aq. fluoronitric acid soln. CONSTITUTION:The implant for in-vivo implantation consisting of the Ni-Ti shape memory alloy is subjected to a cleaning treatment in the aq. fluoronitric acid. The reason for selecting such chemical method lies in that the extremely large surface ruggedness is resulted by mechanical polishing and the good adaptability to the living body is not obtainable. The aq. fluoronitric acid soln. of hydrofluoric acid 1, nitric acid 4 and water 5 is used for the cleaning liquid and the cleaning time is limited to 2-10 minutes. The Ni-Ti shape memory alloy implant in such range has a good surface condition and has the excellent adaptability to the living body. The cleaning is insufficient and an oxide film remains on the implant surface if the cleaning time is <2 minutes. Etch pits are formed on the implant surface and the surface flatness is degraded when the cleaning time exceeds 10 minutes.