Research On Technology Of Micro-arc Oxidation Film Of Titanium Alloy And Its Application

In this thesis, the technology of micro-arc oxidation on Ti6Al4V was investigated.The influence of electrical parameters (such as current density, duty cycle, frequencyand oxidation time) on oxidation film thickness, surface, composition phase and theadhesion within the substrate in the solution of phosphate and calcium acetate wasstudied. The result indicated that a porous film of titanium dioxide would be formed onthe surface of titanium alloy by MAO. The growth and structure of oxidation film canbe affected obviously by electrical parameters. The XRD results showed that the filmis mainly composed of anatase and rutile TiO₂. With increase of current density andduty cycle, and also increase of oxidation time and derease of pulse frequency, thecontent of rutile TiO₂was increased and the size of the micro-porous was alsoincreased, and the number of micro-porous was decreased. The scratch test showedthat the bonding strength between coating and base metal was decreased with increaseof duty cycle and current density, while it was increased with increase of pulsefrequency and oxidation time under constant current condition.Finally, an attempt for application of MAO into titanium anodes pretreatment wasmade in this thesis, The result shows that the stability and the service life of thetitanium anode, which was pretreated by MAO under proper parameters, wasobviously increased over that EDT pretreated titanium anode.