Molten salts thick deposits

Pt electrodeposits may also be produced from molten salt electrolytes. Such a high-temperature process has the advantage that the deposits are diffusion bonded to the titanium substrate and thus have good adhesion, and, if necessary, thick deposits can be produced. However, they have the disadvantage that because of the complexity of the process there is a limitation on the size and shape of the object to be plated, and the resultant deposits are softer and less wear resistant than those from aqueous solutions... 

Through immersion, metals such as copper or silver are deposited from an aqueous solution or molten salt onto the material to be protected. The coating thickness is approximately 1 pm, and the adhesion strength is not always satisfactory. 

A more economical method of making hf structures involves electrochemical deposition from molten salts of a thick niobium layer of a sufficiently high mechanical strength onto a matrix reproducing the inner surface of the article followed by removing the matrix [2,3]. The aim of this work is investigation of physico-mechanical characteristics of niobium coatings obtained by electrodeposition to evaluate the hf superconductivity of the articles which can be made on their basis. 

In discussing molten salt tests, it is useful to consider first thin deposits where diffusion through the deposit of reactants from the gas plays a significant role in the corrosion process, and thick deposits where such diffusion is less important and sometimes negligible. 

TD Diffusion Coating. Carbides are coated on to iron and steel by dipping in a molten salt bath for 1-10 hours. The bath is mainly borax added to low cost carbide precursors. Coatings 5 to 15mm thick are deposited, and cooled in air or by quenching in oil or water to obtain optimum mechanical properties. (Toyota R D Laboratories, Japan. Engrs. Dig. 36, (7), 1975, p27). 

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