METHOD FOR DEPOSITING NICKEL-PHOSPHORUS COATING ON METAL SURFACES Russian patent published in 2016 - IPC C23C18/36 

FIELD: chemistry.

SUBSTANCE: method comprising preparation of the said surface, depositing nickel-phosphorus coating from the electrolyte solution, comprising nickel and phosphorus ions, and adjusting the electrolyte solution to achieve required concentrations of the said ions, pH value and electrolyte volume. The nickel-phosphorus coating was deposited from an electrolyte solution of pH 3.5-5.0, comprising nickel sulphate, nickel chloride, sodium sulphate, sodium hypophosphite and boric acid at a temperature of 80-90°C. The electrolyte solution adjustment was performed throughout the duration of process by continuous dripping of the corrective agent having pH 5.5-7.5 into the said electrolyte at a rate of 2-7 ml/min. per one litre of electrolyte under continuous stirring; the corrective agent comprising the electrolyte mixed with 25-50 ml/l of a 50% solution of potassium hydroxide.

EFFECT: constant electrolyte volume and composition in terms of key ingredients maintained during depositing of nickel-phosphorus coating, stable rate of depositing, uniform chemical composition across the coating thickness, increased service life of the electrolyte.

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