The purpose of this paper is to investigate the possibility of high speed electroforming of nickel at high current density with the flowing electrolyte method of nickel sulfamate solution. Internal stress, hardness and structure of electroformed nickel are determined, and the effects of temperature and flow speed of electrolyte are discussed. The results obtained are as follows:
(1) High speed electroforming of nickel is possible with the flowing electrolyte method of nickel sulfamate solution, and the electroforming rate is almost the same as the rate of Watt's solution.
(2) Internal stress of electroformed nickel from nickel sulfamate solution is in the low state in comparison with that from Watt's solution. Compressive stresses are often observed under some conditions of electroforming. As electrolyte temperature increases, internal stress decreases. Internal stress is affected a little by flow speed of electrolyte.
(3) Low internal stress, in the range of ±5 kg/mm
2 (+ means tensile state, - means compressive state), is observed under the condition that electrolyte temperature is 60°C, flow speed of electrolyte is from 0.8 m/s to 5.4 m/s, current density is from 60 A/dm
2 to 120 A/dm
2.
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