| 摘要 |
A high speed bright nickel electroplate is produced from an acid nickel bath containing coumarin and a secondary brightener using a cathode current density of at least 10 amps/dm2 and maintaining a relative velocity between the bath and the cathode equivalent to 60 to 320 cm./sec. Preferably the nickel bath which may be of the Watts, modified Watts, high chloride, chloride-free (sulphate), or sulphamate type contains at least 0.2 g/1. coumarin and 1 to 10 g/1. of a secondary brightener which may be an aromatic sulphonate, sulphonamide or sulphonimide, e.g. sodium saccharin or dibenzene sulphonamide, and is of pH 3 to 5. The current density may be as high as 120 amps/dm2 and the required agitation of the bath may be effected by rotation or vibration, e.g. ultrasonic, of the cathode, by stirring the bath by means of a propellor, or by pumping the bath over the cathode surface e.g. by directing a stream of the bath through a conduit on to the cathode. |
