抄録
Average internal strain was measured in situ for thin nickel-phosphorus alloy deposits electroplated from nickel-phosphorus baths containing 0.2 to 10mM ZnSO4 as impurity additives using a resistance wire strain gauge placed on the reverse side of the copper substrate.
With increasing ZnSO4 concentration, total zinc oxide and zinc hydroxide included in deposits increased monotonously and average internal tensile strain in deposits also rose. Internal tensile stress rose markedly at 1mM ZnSO4, causing numerous cracks on the surface of deposits at 1.5 to 10mM ZnSO4. At phosphorus content exceeding 12mol%, the development of average internal tensile strain in deposits was independent of phosphorus content, but clearly related to increasing total zinc oxide and zinc hydroxide included in deposits during electroplating.
