Tao Jie

Fabrication and Wear Resistance of TiO2/Al2O3 Coatings by Micro-arc Oxidation

Abstract TiO 2 /Al 2 O 3 composite coatings were prepared on the surface of Ti-6Al-4V alloy by micro-arc oxidation in the Na 2 SiO 3 -(NaPO 3 ) 6 -NaAlO 2 solution. The growth process reveals that O 2- reacts rapidly with Ti 4+ (from substrate) along the reaction channels to form TiO 2 , and because of the addition of AlO 2 − , Al 2 O 3 and Al 2 TiO 5 are simultaneously formed. Al 2 TiO 5 is immediately decomposed into rutile TiO 2 and α-Al 2 O 3 owing to the high thermal energy caused by discharge. Finally the prepared composite phase coatings are mainly composed of anatase TiO 2 , rutile TiO 2 and α-Al 2 O 3 via XRD analysis. Furthermore, the microhardness HV increases and maintains at about 11 000 MPa, and the wear resistance of the TiO 2 /Al 2 O 3 composite coatings is enhanced by about 9.5 times than higher that of Ti-6Al-4V alloy owing to the existence of ceramic layer.

Explosive Cladding and Hot Pressing of Ti/Al/Ti Laminates

Abstract Ti/Al/Ti laminates were prepared by an explosive cladding method. Then hot pressing was employed to further process the laminates. The results indicate that both linear and wavy bonding interfaces coexist and element diffusion occurs in the interfacial zone between the titanium and aluminum layers after explosive cladding. After 25 h heat treatment and 2.5 h hot pressing, the aluminum layer is consumed completely. The reaction layer consists of Al3Ti and Ti2Al5 phase.