As usual Kurt, thanks for the contribution.
One thing I might add, as someone who works with many tons of W a year...when the W contacts are "done" you should have a yellow powder of WO3 left behind.
W is some tricky stuff and I've learned quite a bit about it dealing with aerospace superalloys. It will slowly cement Pt out of solution because even aqua regia doesn't readily act on it.
Better solvents for W are NaOH + NaOCl, NaOH + dropwise H2O2.
One thing I might add, as someone who works with many tons of W a year...when the W contacts are "done" you should have a yellow powder of WO3 left behind.
W is some tricky stuff and I've learned quite a bit about it dealing with aerospace superalloys. It will slowly cement Pt out of solution because even aqua regia doesn't readily act on it.
Better solvents for W are NaOH + NaOCl, NaOH + dropwise H2O2.