Surface treatment of stainless steel to improve coating strength of ZrO 2 coated stainless steel needle

Abstract

In the present study, stainless steel 316L was coated with ZrO₂, a bioceramic, to insulate the needles and improve their biocompatibility. Three types of stainless steel 316L specimens were used in the experiment: an untreated specimen (case 1), an electropolished specimen (case 2) and an electropolished and plasma treated specimen (case 3). The effects of electropolishing and plasma treatment on coating strength and the relationship between coating thickness and electrical conductivity were investigated. The result showed that the coating strength of case 3 was 130% greater than that of case 1 and 40% greater than that of case 2. The electrical insulation characteristic of ZrO₂ coating on stainless steel 316L was superior to that of uncoated stainless steel 316L. It was also found that appropriate thickness of ZrO₂ coating was 500 nm for the electrical insulation.