Gold Electroplating

The deposition of gold by electroplating has more advantages than the simple chemical deposition by immersion or gilding process. In gilding by dipping, or simple immersion, it is obvious that, as a rule, only a limited amount of gold can be deposited upon the work, and that the application of this method of gilding, therefore, must be confined to cheap classes of work, or to articles which will not be subjected to much friction in use. In gold electroplating by the application of an electric current, on the other hand, it is possible to obtain a deposit of the precious metal not only of any required thickness, but also upon many articles which it would be practically impossible to gild properly by simple immersion in a solution of gold.

Gold electroplating is performed either with hot or cold solutions; but for most practical purposes hot solutions may be employed. When gold is deposited from cold solutions, the colour of the deposited metal is usually of a yellow colour, and not of the rich orange-yellow tint which is the natural characteristic of fine gold; the deposit, moreover, is more crystalline, and consequently more porous in cold than hot solutions, and is therefore not so good a protective coating to the underlying metal. The gold deposited from hot solutions is not only of a superior colour and of closer texture, but it is also obtained with much greater rapidity; indeed, from the moment the articles are immersed in the electroplating bath, all things being equal, the colour, thickness, and rapidity of the deposit are greatly under the control of the operator. In a few seconds of time an article may be gilded of the finest gold colour, with scarcely an appreciable quantity of the precious metal, while in the course of a very few minutes a coating of sufficient thickness may be obtained to resist a considerable amount of wear.

The superior conductivity of hot electroplating solutions enables the operator to treat many metallic surfaces, as tin, lead, Britannia metal, and steel, for example, which are difficult to treat satisfactorily with cold solutions; moreover, hot electroplating solutions readily dissolve any trace of greasy matter, or film of oxide which may be present on the surface of the work, through careless treatment, and thus clean the surface of the work for the reception of the gold deposit. Since cold electroplating solutions are also used in electro-deposition of gold, these may be used for special purposes. The final election must be based on the use of the article due to the environment is different in each case.