Characterızatıon Of Az91 Magnesıum Alloy Produced By Pm Method Coated Wıth Tantalum Oxıde By Usıng Sol-Gel Method


Thesis Type: Postgraduate

Institution Of The Thesis: Gazi Üniversitesi, Fen Bilimleri Enstitüsü, Turkey

Approval Date: 2019

Student: CANSER GÜL

Supervisor: HANİFİ ÇİNİCİ

Abstract:

Biomaterials are materials developed to replace damaged tissues and organs in the human body or in order to assist these tissues and organs. The most important feature in biomaterials is biocompatibility, which means that the biomaterial does not cause any unfavorable reactions in the human body. AZ91 Magnesium alloy has biocompatibility. It is replaced with the healthy tissue in time by dissolving in the body, especially is prone to use in implant applications because of its feature. Due to the similarity to the cortical bone, in terms of having light weight, its density value and mechanical properties, studies are being carried out for use in the permanent implant applications, too. It is possible to produce them by casting or powder metallurgy methods. Tantalum element is known to have good biocompatibility and optical properties. In this thesis, it was aimed to minimize the corrosion of the AZ91 Mg alloy with prepared by surface modifications and by coating with different dipping numbers Ta2O5 to increase the lifetime of this alloy in the body. For this purpose, coated substrate materials were produced by hot pressing of AZ91 Mg alloy powders using uniaxial press. Produced samples were cut in dimensions as 60×10×2 mm3 and after that their surfaces were sanded till 1200 grit by mechanical grinding. Grinded surfaces of samples were subjected to surface treatment with etching and NaOH solution and cleaned in ultrasonic bath. The samples having sanded surfaces were made prepared for coating process by cleaning in ultrasonic bath. The coating solution was prepared and the thermal properties of this solution and attainability of Ta2O5 were examined by using thermo gravimetric differential thermal analysis (TG-DTA). Ta2O5 coatings were made by sol-gel and dip coating methods on the prepared substrates. The coated samples were dried in the drying oven for 1 hour at 100 °C and finally sintered at 400 °C. The structural properties of these samples were examined by X-ray diffraction method (XRD), Scanning electron microscopy (SEM) with energy dispersive spectrometry technique (EDS). The corrosion behavior of these samples was obtained with potentiodynamic-electrochemical corrosion test by using the simulated body fluid. As a result of the tests, it was observed that the thickness of the coatings and the corrosion resistances increase with the increase in the number of dipping and the surface modification applied.