Corrosion protection of titanium by pulsed plasma deposition of palladium

The potential of pulsed ion deposition of palladium, using several coating conditions, for the corrosion protection of titanium foil in 0.1 M H2SO4, 0.1 M HNO3 and a mixture of equal volumes of the two acids at 80 degrees C has been investigated by weight loss measurements, scanning electron microscopy and Rutherford backscattering spectroscopy. The environments were selected to evaluate the possible application of the coated foil for the electron-transparent window of the Electron Beam Dry Scrubber Process for clean-up of Rue gas. The resultant coated foil had significantly enhanced corrosion resistance compared with the untreated foil for all coating conditions. However, the coating material was susceptible to local or general detachment during immersion in acid, most noticeably in H2SO4. The detachment usually initiated at flaws in the coating and may be related to local generation of hydrogen, a stress-corrosion cracking process, or the presence of oxygen in the coating. Nevertheless, exposed regions of underlying material were resistant to corrosion due to a remaining layer of Ti-Pd alloy. (C) 2000 Elsevier Science Ltd. All rights reserved.