Improving surface features of PEO coatings on titanium and titanium alloys with zirconia particles: A review

Plasma electrolytic oxidation (PEO) can be utilized for the in-situ ceramic coatings preparation on the surface of metals as a low cost and high efficiency surface modification method. In this technique, coatings having various surface compositions and morphologies and distinct properties can be provided by altering the electrical parameters and the composition and concentration of the solutions. The addition of particles of certain sizes into the solutions is beneficial in enhancing the function of PEO coatings. An example is zirconia (ZrO2) which is known as an effective additive in improving properties of PEO coatings which helps the coatings to have attractive features such as appropriate corrosion and wear resistance, high hardness, and excellent biocompatibility. The added ZrO2 particles to the solution improve the properties of the titanium oxide (TiO2) PEO coated titanium and its alloys by producing TiO2/ZrO2 composite. The present article reviews the studies which have investigated the influences of ZrO2 particles addition on mechanical and physical properties, wear and corrosion behavior, biological responses, and oxidation resistance of PEO oxide films applied on titanium and its alloys.