I am currently testsing some nickel alloy samples in ASTM 28B (H2SO4, HCl, CuCl2, FeCl3)solution. After one test it turned dark green. I kept using the same solution to see whether it has still corrosivity to corrode samples. I have done 3 tests but still it seems to give some results. The ASTM standard does not tell when to change solution. My questions are
1. How many tests/samples can the solution handke before discarding?
2. How do I know the solution is no good? Any easy method to find out - pH measurement, etc?
3. How do I safely dispose the used solution?
4. How to avoid (thin) copper coating on samples?
many thanks.
1. How many tests/samples can the solution handke before discarding?
2. How do I know the solution is no good? Any easy method to find out - pH measurement, etc?
3. How do I safely dispose the used solution?
4. How to avoid (thin) copper coating on samples?
many thanks.
