CHARACTERISATION OF BIOMEDICAL TITANIUM LAYERS DEPOSITED BY A VACUUM PLASMA SPRAY PROCESS

Mihailo Mrdak; Darko Bajić; Darko Veljić; Marko Rakin

doi:10.17222/mit.2020.135

Mihailo Mrdak University of Belgrade, Innovation Center, Faculty of Technology and Metallurgy, 4 Karnegijeva Str., 11000 Belgrade, Serbia
Darko Bajić University of Montenegro, Faculty of Mechanical Engineering, Bul. Džordža Vašingtona bb, 81000 Podgorica, Montenegro
Darko Veljić University of Belgrade, Innovation Center, Faculty of Technology and Metallurgy, 4 Karnegijeva Str., 11000 Belgrade, Serbia
Marko Rakin University of Belgrade, Faculty of Technology and Metallurgy, 4 Karnegijeva Str., 11000 Belgrade, Serbia

DOI: https://doi.org/10.17222/mit.2020.135

Keywords: vacuum plasma spray process, titanium, microstructure, microhardness, bond tensile strength

Abstract

In this paper we will describe the process of the deposition of thick layers of VPS-Ti coating, which is used as a bonding layer for the upper porous Ti coatings on implant substrates. In order to deposit the powder, we used HÖGANÄS Ti powder labelled as AMPERIT 154.086 -63 µm. In order to test the mechanical properties and microstructure of the VPS-Ti coating, the powder was deposited on Č.4171 (X15Cr13 EN10027) steel substrates. Mechanical tests of the microhardness of the coating were performed by the Vickers hardness test method (HV_0.3) and tensile strength by measuring the force per unit area (MPa). The microhardness of the coating is 159 HV_0.3, which is consistent with the microstructure. The coating was found to have a good bond strength of 68 MPa. The morphology of the powder particles was examined on a scanning electron microscope. The microstructure of the coating, both when deposited and etched, was examined with an optical microscope and a scanning electron microscope. By etching the coating layers, it was found that the structure is homogeneous and that it consists of a mixture of low-temperature and high-temperature titanium phases (α-Ti + β-Ti). Our tests have shown that the deposited layers of Ti coating can be used as a bonding layer for porous Ti coatings in the production of implants.

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