Abstract
An internal strain in deposits and amount of hydrogen evolved at the beginning of iron electroplating were evaluated, and the influence of hydrogen evolution on the internal strain was also discussed. The internal strain was measured using resistance wire type strain gauge put on the reverse side of copper electrode. On the other hand, the amount of hydrogen gas evolved during iron electroplating was in-situ evaluated from its buoyancy produced by hydrogen gas using electromagnetic balance.
The hydrogen evolved during iron electroplating influenced greatly on the formation of internal strain in iron deposits. Especially, a part of hydrogen codeposited with iron spontaneously leaked from the iron crystal to the outside, which caused an internal tensile strain in iron deposits. The measurement of buoyancy produced by the hydrogen gas using electromagnetic balance also enabled us to evaluate the amount of atomic hydrogen that incorporated in iron deposits during electroplating and then released after anodic dissolution of the iron deposits.
A large portion of hydrogen evolved at the beginning of the electroplating was included in iron deposits and the hydrogen content was ca 16mol.% at current density of 30mA/cm2. However, after consecutive iron electroplating of only 1.3C/cm2 the hydrogen content in deposits decreased greatly to ca 5mol.%.
