GB1051624A - - Google Patents

Abstract

1,051,624. Acid zinc electroplating baths. PERNIX ENTHONE. May 20, 1964 [May 21, 1963], No.20905/64. Heading C7B. Bright zinc is electrodeposited from an acid zinc plating bath comprising a zinc compound and an inorganic acid and containing an aldehyde solubilized by a solubilizer in an appropriate solvent and a meat protein hydrolysate. Preferably the latter which is derived from meat which has been degraded by means of a proteolytic e.g. pancreatic enzyme is added to the bath before the aldehyde and the precipitate of fatty acids and hydrocarbons produced on adding the solubilized aldehyde should be filtered off before using the plating bath as they tend to cause pitting. Specified aldehydes are aliphatic aldehydes containing at least 5 carbon atoms, e.g. 2-methyl-2-ethyl-3-dydroxy-propionaldehyde, or an aromatic aldehyde in which a benzene ring has one or more substituents in the p- or o- and ppositions, such as vertraldehyde, anisic aldehyde, piperonal, vanillin, hydroxybenzaldehyde, or 2:4 - dichlorobenzaldehyde. The aldehyde solubilizer disclosed is sodium bisulphite which should not be present in molar excess with respect to the aldehyde. An antipitting surfactant such as an alkali metal alkyl sulphate or an aromatic sulphonic acid may be included in the bath and a preservative such as 2:4:5-trichlorophenol may also be present. The plating bath may comprise zinc sulphate, boric acid, ammonium chloride or fluoride and optionally zinc chloride, zinc acetate or aluminium sulphate and is used in a temperature range of 80 to 130‹F.