The improved corrosion resistance and anti-wear performance of Zr–xTi alloys by thermal oxidation treatment

Abstract

Abstract By thermal oxidation treatment at 500 °C in air, the monoclinic ZrO 2 and orthorhombic ZrTiO 4 oxide coatings were in-situ formed on the surfaces of biomedical Zr–20Ti and Zr–40Ti alloys, respectively. The hardness and adhesion strength of the oxide coatings were measured by indentation and scratching tests. The electrochemical corrosion of the Zr– x Ti alloys before and after thermal oxidation treatment was performed in the acidified artificial saliva containing 0.1% NaF at 37 °C. The friction and wear performances of the un-oxidized and oxidized Zr– x Ti alloys were evaluated by reciprocating ball-on-disc wear tests under the load of 10 N. The results show that the oxide coatings have the hardness of 1420–1480 HV and the adhesion forces of 51 N to the substrates. The oxidized Zr– x Ti alloys exhibit the reduced corrosion rates and improved pitting corrosion resistance in comparison with the un-oxidized Zr– x Ti alloys. The wear tests demonstrate that the un-oxidized Zr– x Ti alloys show the serious adhesive wear and abrasive wear due to the high plasticity and chemical activity. The coefficients of friction and wear rates of the oxidized Zr– x Ti alloys decrease 30% and 90%, respectively, which are attributed to the hard oxide coatings with enhanced toughness. Nevertheless, the scabies defects in the oxide coating of Zr–20Ti alloy have a negative effect on the friction and wear property. The oxidized Zr–40Ti alloy has the excellent chemical stability and anti-abrasion performance. It has a great application prospect as dental implant material.