부산대학교 도서관

Determination of titanium in stainless steel and heat-resistant alloy was made by polarographic method with phosphoric acid as a supporting electrolyte. Cu2+, Ti4+, Pb2+, Mo6+, and W6+ in phosphoric acid solution gave quantitative polarographic waves. Molybdenum showed a two-step wave, the half-wave potential of which was close to that of titanium, and interfere with the determination, while lead and tungsten were without influence due to their post discharging nature. Although copper had shown a pre-discharging nature, it had no disturbing influence by the presence of twice as much weight oftitanium and the simultaneous determination of titanium and copper was possible.The sample (0.21g) was decomposed with aqua regia and this was heated with 30ml perchloric acid till the evolution of white fumes. It was diluted to 50ml, and an aliquot of 10ml was boiled with 20ml 2% hydrazine sulfate for reduction of iron, etc. The solution after cooling was transferred into 50ml measuring flask, 10ml phosphoric acid and 1ml 0.2% gelatin solution were added and the whole was made up to the mark with water. The polarogram of the solution from -0.2 to -0.9V was taken by the conventional method and the amount of titanium was calculated.In case of the steel containing molybdenum, the sample after white fuming treatment with perchloric acid was diluted, made alkaline with ammonia for precipitation and separation of titanium after an addition of EDTA for masking of Fe etc. The precipitate on the filter paper was dissolved with 60ml of warm phosphoric acid (1+2) in several portions. Gelatin solution was added and the whole was made up to 100ml with water.Good result was obtained for determination of 0.24% titanium by the recommended method.