Spectre50
Mechanical
- Feb 17, 2014
- 10
We are using a cyanide based electrochemical etching process to etch tapered tips on a precious metal alloy wire and have discovered that each material lot behaves differently with the same etch process. These material lots will preferentially etch the grains in one lot and varying levels of the grain boundaries in the next lots. We have etched these material lots in the same batch and have achieved the same grain boundary etch results. I have found out that that the lots we have purchased are from the same pour but were heat treated at different times. We have analyzed the exact hardness of the lots and found that the degree to which the grain boundaries is etched does not follow the hardness of the material. What material properties would cause the preferential etching of the grain boundary to varying levels or the preferential etching of the grains? The EDX that we had performed showed no differences in composition but that testing is qualitative anyway.