Chemically Milled Alpha-Case Layer from Ti-6Al-4V Alloy Investment Cast
The as cast Ti6Al4V, obtained after investment casting with yttria stabilized zirconia face-coat, was chemically milled using a mixture of hydrofluoric acid and nitric acid. This process removed completely the alpha-case layer. Lower hardness and almost no oxygen contamination are revealed after microhardness measurement, Energy dispersive X-ray and X-ray diffraction analysis. The hydrofluoric acid/nitric acid ratio, pickled Ti6Al4V surface, pickling efficiency, pickling rate, immersion time and solution temperature are discussed.
Hajo Dieringa, Norbert Hort and Karl Ulrich Kainer
K. Mutombo et al., "Chemically Milled Alpha-Case Layer from Ti-6Al-4V Alloy Investment Cast", Materials Science Forum, Vol. 690, pp. 477-480, 2011