Solutions for Stripping Cadmium Plate

Electrodeposited cadmium can be stripped chemically from the basis metal by immersion in one of the following solutions: ammonium nitrate, inhibited hydrochloric acid, chromic acid with a sulfuric acid addition, and ammonium persulfate with an ammonium hydroxide addition. Electrolytic stripping is performed in a solution of sodium cyanide with an addition of sodium hydroxide. Compositions of these stripping solutions, and the immersion times to be used with them, are given in Table 12.

Table 12 Solutions for stripping electrodeposited cadmium

Solution00

Composition

Amount

Immersion time, min(b)

g/L

oz/gal

1

Ammonium nitrate

105-136

14-18

10-20

2(c)

Hydrochloric acid (1.18 sp gr), undiluted

10-20

Antimony trioxide

15

2

3

Chromic acid

203

26.8

5-10

Sulfuric acid (95%)

48(d)

6.4(e)

4

Ammonium persulfate

51

6.7

5-10

Ammonium hydroxide

96.8(d)

12.8(e)

5(f)

Sodium cyanide

60-91

8-12

10-20

Sodium hydroxide

15-30

2-4

(a) Solutions are listed in order of preference; all solutions are used at room temperature.

(b) Immersion times are for deposits 8 to 13 ^m (320 to 520 ^in.) thick.

(c) Solution should not be used on stressed or hardened parts.

(f) Solution for stripping electrolytically; 540 to 1080 A/m2 (50 to 100 A/ft2) and 6 to 8 V; part to be stripped is made the anode.

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