STUDY ON MICROSTRUCTURE, MECHANICAL, AND CORROSION PROPERTIES OF B-ADDED CO-CR-W-NI-MN ALLOYS FOR HEART VALVE IMPLANT APPLICATIONS

• Main Author: Ilham Maulana, Muhammad
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/71615
• Institution: Institut Teknologi Bandung

Co-based metal alloys are future biomaterials for heart valve implant applications due to their excellent biocompatibility, mechanical, and corrosion properties. The CoCrWNiMn alloys, one of cobalt-based alloys, is currently being researched as a biomaterial. Boron has long been used as an alloying element which is added in certain amounts to several alloys. In this study, boron was used as an alloying element in the CoCrWNiMn alloys to modifying its mechanical and corrosion properties. The CoCrWNiMn alloys was prepared from cobalt, chrome, wolfram, nickel, mangan, and boron chunk metals using vacuum arc remelting under Argon atmosphere. The Vacuum Arc Remelting (VAR) process for each sample was carried out 6 times by back and forth to obtain a uniformity distribution of elements in each part. The microstructure, mechanical, and corrosion properties of the CoCrWNiMn-×B alloys were analyzed. This analysis included optical microscopy observations, SEM-EDS mapping observations, OES, XRD, hardness test, tensile test, density test and corrosion performances of CoCrWNiMn-×B alloys in Hanks' solution. The results showed that boron addition up to 0.8 wt% in the CoCrWNiMn alloys did not change phases significantly, but led precipitates at grain boundaries on the sample morphology. Hardness and tensile strength properties of the CoCrWNiMn alloy increased with boron addition. CoCrWNiMn alloys with 0.8 wt% boron addition produced the highest hardness and yield strength values in 32.74 HRC and 439.27 MPa. The corrosion performances of the CoCrWNiMn alloys in Hanks' solution decreased with boron addition. In-vivo corrosion results showed that the CoCrWNiMn alloys with 0.8 wt% boron addition had the highest electrical resistance, which leads a decrease in the corrosion rate.