A comparative corrosion study of titanium strips produced by wrought and direct powder rolling processes

Abstract

Titanium is a light metal that has a high strength to weight ratio compared to steel. It has good corrosion resistance and is biocompatible. However, due to its high costs, its use has been limited mainly to the aerospace and medical industries. Direct powder rolling (DPR), a powder metallurgy (PM) method, is being developed with the aim of reducing the cost of producing titanium flat mill products. Critical to the success of the DPR produced products will be their ability to match or exceed the properties and performance behaviour of the equivalent products produced by wrought metallurgy. Titanium strips that are 89 % and 98 % dense were produced by DPR and their corrosion behaviour was compared to the wrought produced titanium strips. The corrosion tests were carried out in 1.75 wt.%, 2.0 wt.% and 3.5 wt.% NaCl solutions kept at 23 °C using potentiodynamic polarization. The polarization curves showed that the wrought strips were the most corrosion resistant, followed by the DPR-98 % then the DPR-89 %. The influence of pores on the corrosion behaviour was high, therefore, effort needs to be made to reduce the pores of the DPR samples.