EFFECT ADDITION OF TIN AND SOLUTION HEAT TREATMENT ON MICROSTRUCTURE AND CORROSION RESISTANCE OF NITINOL

• Main Author: ADAM (NIM : 12513038), ZAKI
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/24848
• Institution: Institut Teknologi Bandung

World population is projected to increase about 1,1 billion in the end of 2030. The increment of world population will have an impact on the escalation of primary human needs. One of them is human health. Biomaterial is widely used as an alternative in health industry. Biomaterial projected to increase about 10,3% compound annual grow rate (CAGR) in 2020. Nitinol alloy is commonly used as a biomaterial because it has a good biocompatibility and able to undergo elastic deformation up to 10% strain, similiar to the nature of biological structure of bones and tendon. Nitinol alloy are feared to cause allergies due to dissolution of Ni elements in the human body. The addition of tin (Sn) to the nitinol alloy is known to maintain the unique properties of this alloy. Sn is also an element that widely used in the food industry. In addition, Sn is known to improve fracture resistance of nitinol alloy <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> A series of experiment has been conducted to study the addition of Sn in Nitinol alloy on microstructure and corrosion resistance. Solution Heat Treatment is conducted in horizontal tube furnace at 750&#8451; and 850&#8451; in an inert condition followed by quenching in cold water. In this experiment, sample will be characterized to understand microstructure and distribution of alloying element by using optical microscope, X-Ray Diffractometer, Scanning Electron Microscope – Energy Dispersive Spectroscopy (SEM-EDS). In addition to microstructure analysis, a corrosion test is also performed using an extrapolation tafel method to determine the corrosion rate. <br /> <br /> <br /> <br /> The result shows that addition of 1-2% Sn resulted in formation of single phase Ni-Ti with dissolve Sn. In addition, there is an indication of martensitic transformation in term of morphological differences in the microstructure. Island morphology is found in Sn-added sample whereas common morphology of nitinol alloy is in needle form. EDS and xray mapping results show that alloying element is homogen throughout the sample. Addition of 1,5% Sn with solution heat treatment at 850&#8451; shows the lowest corrosion rate at 0,0007 mmpy, while alloy with no Sn addition have corrosion rate of 0,0184 mmpy. <br />