Abstract

BALOYI, N.M.; POPOOLA, A.P.I.  and  PITYANA, S.L.. Laser coating of zirconium and ZrO₂ composites on Ti₆Al₄V for biomedical applications. S. Afr. J. Ind. Eng. [online]. 2014, vol.25, n.1, pp.62-70. ISSN 2224-7890.

Coating is a technology for improving the surface properties of components. Laser coating produces uniform composition with thickened layers that display a good metallurgical bond to the base material. These coatings are dense and crack-free, and have non-porous microstructures. The advantages of the process are that the components' surface will have high resistance to wear and corrosion, even at elevated temperatures. In this work, Ti₆Al₄V base material was coated with zirconium and zirconia composite material to improve the base material's resistance to corrosion and wear. Zirconium powder mixed with binder (PVA and cold glue) was melted to produce a thin layer, which was then bonded to the Ti₆Al₄V by irradiation with a fibre laser, thus forming a zirconium + zirconia composite due to an in-situ reaction in the liquid state. The presence of binder in the Zr powder indicated a change in the microstructural behaviour, as the results showed a gradual increase in the hardness of the coated Ti₆Al₄V from top to bottom. It was also found that Zr + PVA binder coating was uniformly deposited, and had a less dendritic structure compared with Zr without binder or Zr with cold glue.

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