I have had troubles in my first experiencies anodizing Ti6Al4V. I
get a brown colour with little white spots and traces. Also, in some
areas, were formed gray small areas with the texture of iron oxide.
In other areas is possible to see some of the interference spectrum
I used some commercial batteries in series, with a total voltage of
near 16 volts. Also tried with a 30 volts printer power supply, with
more aggressive results: the surface plenty of grey spots.
With the same setup I get a good blue colour using grade 2 titanium,
then it seems that the setup is not the problem.
The Ti6Al4V piece of titanium was a second hand one. I burnt some
lathe chips and saw a intense flame that makes me think that it’s
real Ti6Al4V titanium. But also, I bought some second hand Ti6Al4V
solid bar pieces from other place, with the same results.
Does anybody know what’s the matter?