Surface modification of SUS 304 stainless steel for biomedical application
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Date
2016-06
Authors
Nur Faiqa Mohamed Niza
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Abstract
SUS 304 stainless steel is known as a biocompatible material and its applications in medical fields are widely used, especially for implant as screws or plates. In medical implantation, issues regarding iron release and toxic production effect inside the human body become a concern which limit the application of SUS 304. To overcome this shortcoming, modification of SUS 304 surface is needed. To enable SUS 304 to be biocompatible and can deposit calcium ions, calcium ion will be deposited on the SUS 304 by subjecting to electrolysis in NaCl solution to form pitting corrosion before the substrate is immersed in calcium phosphate solution. The effect of calcium coating in different electrolysis times and hydrothermal times have been studies which were electrolysis time within 15, 30, 45, and 60 minutes and hydrothermal treatment for 24, 36, 48, and 60 hours. Results obtained showed that for 15 minutes of electrolysis, the calcium ion was not fully modified the surface of the substrate treated for 24 hours as compared to the substrate treated for 36, 48, and 60 hours. Moreover, for 30, 45, and 60 minutes electrolysis, the calcium ions were constantly increased due to the longer hydrothermal treatments. Hardness tests performed by Rockwell hardness testing method showed decreasing values for SUS 304 samples coated with calcium ion. As a result, increasing the hydrothermal treatment time lowered the hardness of the surface layer. Adhesive tests conducted by Universal Instron Mechanical Testing Machine results showed that the longer the duration time for the electrolysis, the faster duration time of hydrothermal treatment is required to increase the adhesion strength of the calcium attachment on the surface of SUS 304.