Symposium on Industrial Electrochemistry and Electrochemical Engineering General Session held during the 229th Meeting of The Electrochemical-Society, California, United States Of America, 29 May - 02 June 2016, vol.72, pp.13-21
Among Fe-Ni-Co alloys, Kovar (53%Fe-29%Ni-17%Co) designated as ASTM F-15 (1), is a well-known glass-sealing alloy. It is also classified as low-expansion alloy (2). Low expansion is required to avoid internal stresses in applications that involve strong ceramic to metal joining such as in vacuum systems (3-6). Electropolishing is applied to obtain smooth metallic surfaces to gain low outgassing rates from the chamber walls in vacuum applications (7-9). The effects of current density, perchloric acid concentration and bath temperature on surface roughness and thickness change were investigated in acetic acid-perchloric acid electrolyte. It was found that current density, perchloric acid concentration and temperature of the bath had a decreasing influence on surface roughness in the given order. On the other hand, thickness change was found to have a direct correlation with the current density and was independent of bath concentration and temperature.