2007-05-18T15:01:09Z PunBB http://www.finishingtalk.com/community/topic302$2.html I found the answer. Analysis XPS has not detected iron on the surface. Wet chemistry too. So, with conditions of acid mix (HF :2 % and HNO3- : 35%), it's impossible to link titanium of other part of the alloy with iron. Yustin 2007-05-18T15:01:09Z http://www.finishingtalk.com/community/post687.html#p687 Hi, We have done an ICP analysis on basic elements (Fe, Si, Cr, Ti...) in solution in a mix of acid (nitric acid 35%, hydrofluoric acid 1.5%). The results indicate a concentration around 12-15 mg of iron/L while the maximum limit allowed is 0.1mg/L in local water. I would like to know if this concentration could enhanced oxidation on titanium base alloys (Ti:82%; Al:6%; Mo:6%; Zc:4%; Ti: 2%). What are the reactions that could give raise of orange coloration ? Regards Justin Yustin 2007-04-23T18:57:24Z http://www.finishingtalk.com/community/post644.html#p644