Abstract: The invention provides method and apparatus for chemical milling of a metal part in a milling solution that reduces hydrogen absorption by the part wherein, the metal part to be milled, which serves as the anode, and a cathode of more noble metal than the anode, are mounted in such solution. Unlike the prior art, the cathode and anode are separated in such solution but electrically connected by a conductor therebetween, which conductor is insulated from the milling solution. Thus anode and cathode are mounted, spaced apart in the milling solution, so that metal dissolves from the anode surface, milling such part while electrons flow from anode to cathode by said conductor so that hydrogen forms at the cathode, removed from the anode part, to reduce hydrogen absorption by such part.The anode part can be of, eg. titanium and the cathode of a more noble metal, eg. platinum, which serves to draw the hydrogen to the cathode and away from the anode part, preventing or reducing absorption of hydrogen into, eg.

Abstract: A method is disclosed for protecting a force-transmitting or force-receiving surface of titanium from fretting fatigue. The method constitutes coating the surface with a coating of an alloy of nickel, cobalt, and iron.

Abstract: A process is described for the chemical processing of beta phase-containing titanium alloys. The process includes the addition of copper, ruthenium, rhodium, paddadium, osmium, iridium, platinum or gold to the acid solution which effectively suppresses hydrogen absorption and the attendant hydrogen embrittlement. The metal concentration ranges from 0.001 millimoles/liter for cleaning and bright polishing operations up to 200 millimoles/liter for chemical milling.