1.Cleaning:<br />The following cleaning treatments may be used for all conditions and types of electrodeposited nickel. The choice of the procedure will be governed largely by the condition of the surface.<br />1.1. Degreasing—Degreasing is used to remove the bulk of grease, oil, and buffing compounds that may be present on the surface. The cleaning may be effected with vapor degreasing, organic solvents, emulsion cleaners, or soak cleaner.<br />1.2. Electrolytic Alkaline Cleaning—Removal of final traces of dirt, grease, and oil is accomplished best with electrolytic alkaline cleaning. The solution may be either a proprietary cleaner or a formulated one. Since a nickel surface forms an oxide coating if treated anodically in an alkaline solution.<br />2. Activating<br />The procedure used for etching or activating the nickel surface.<br />2.1 Anodic Treatment in Concentrated Sulfuric Acid- (Nickel removed nil). A70 mass % sulfuric acid solution containing 661 mL of concentrated, 96 mass % sulfuric acid (density 1.83 mL) diluted to 1 L may be used for activating the nickel surface provided the temperature of the solution is not over 30°C The time of treatment should be about 1 min at a current density of 10 A/dm2. At this current density the nickel normally goes passive and a bright surface becomes only slightly dull. This type of passivity is removed by subsequent rinsing in water.<br />Warning-Slowly add the sulfuric acid with rapid stirring to the approximate amount of water required.<br /><br />2.2 Cathodic Treatment:<br /> Prior cleaning may be required, such as alkaline soak cleaning or electrocleaning, or both. If electrocleaning is employed, only cathodic current should be used. In the following formulations, 96 mass % sulfuric acid with a density of 1.83 g/mL, and 37 mass % hydrochloric acid with a density of 1.16 g/mL, are used.<br />Cathodic Treatment in Sulfuric Acid:<br /> <br />Cathodic Treatment in Hydrochloric Acid:<br /><br /><br /><br /> <br /><br /><br /><br />