GB1354078A - Zinc electroplating - Google Patents

Abstract

1354078 Zinc plating bath HENKEL & CIE GmbH 14 April 1972 [16 April 1971] 17209/72 Addition to 1285256 Heading C7B An acid (e.g. pH 3-5) lustrous Zn electroplating bath has a Zn salt, e.g. ZnCl 2 or ZnSO 4 , optionally a further conducting salt, e.g. NH 4 Cl, AlCl 3 or Al 2 (SO 4 ) 3 , with boric acid or sodium acetate, with conventional lustring and/or wetting agent, and, as lustring agents, (1) a thiourea derivative of the formula: R-NH-CS-NR 1 R 2 , in which R is a saturated aliphatic C 6-22 hydrocarbon, a mono- or poly-nuclear (aliphatic or aromatic substituted) aryl, an alkylaryl or a cycloaliphatic residue, R 1 is a straight or branched chain hydroxy C 2-6 alkyl residue, preferably interrupted by one or more ether groups e.g. (oxyethoxy)-ethyl or -propyl; and R 2 is H or R 1 , with (2) an aromatic carbonyl compound of the formula R-A-CO-R 1 , in which R is an aromatic residue, A is a C 1-4 aliphatic bridging member which may be omitted, and R 1 is an aliphatic residue which may be substituted by ester-, carboxyl- or carbonyl groups. Examples of aromatic carbonyl compounds are acetophenone, benzoyl acetic acid (ethyl ester), benzoyl acetone, benzal acetone (α-acetyl naphthalene). A ZnCl 2 bath may contain as wetting agent an addition product of ethylene oxide to a higher M. W. aliphatic (e.g. isononyl) alcohol or alkyl (e. g. nonyl) phenol. A ZnSO 4 bath may contain as wetting agent a fatty alcohol (ether) sulphate or polyalkylene glycol. A current density of 0À5-8A/dm<SP>2</SP> may be used. Specification 1285254 is referred to.