Radioisotope tracer techniques were used to study the following phenomena:(l) The effect of the nickel dip on the deposition of cobalt metal during firing of a cobalt-bearing ground coat on pickled and sand-blasted iron, (2) the effect of surface pretreatment on the amount and distribution of nickel deposited from the nickel dip on enameling iron, and (3) the effect of application and firing of cobalt-free and cobalt bearing:enumels on the chemical form and physical distribution of nickel previously deposited on enameling iron by the nickel dip.nThe use of radioactive nickel in the nickel-dip solution was found to oiler several advantages for studying the deposition of nickel by this process. Autoradiographs give an informative picture of the actual dis¬tribution of the deposit with good resolution. Radioassays are a quick, nondestructive method of determining the amount of nickel deposited, and radioassays were made on the same area of specimens at various stages in the processing to evaluate the effect of various treatments on the amount of nickel retained by the iron.
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