The discovery and production of good anodes were vital to the success of nickel plating. I should love to tell this fascinating story, but I shall refrain and limit these comments to those developments that have been most influential. First, there was the discovery by Isaac Adams, who described his invention about 1869 and who must be credited with the first practical nickel anode, even though W.H. Remington patented a less useful one in 18681,57. Then came the high-iron anodes, which dissolved readily, but caused trouble in low-pH electrolytes. The Watts bath made additional improvements possible. Consequently, the high-iron anode was followed by ones of much higher purity containing as much as 99 percent nickel and varying amounts of carbon, which prevented loose nickel from falling into the bath by forming a film on the surface of the anodes as they corroded. An anode containing oxidized pitch enjoyed modest success, but it was difficult to cast. By the 1920s, the use of anode bags had become common, and electrolytic nickel was available at reasonable prices, thus tempting platers to try using electrolytic strips for anodes. But pitfalls were legion; most attempts to overcome the disadvantages had only isolated success. Nickel anodes had come a long way by the end of the 1920s, but the industry still did not have a consistently reliable product.
The need was met in stages. In 1930, Harshaw, Savage and Bezzenberger patented a rolled anode depolarized with oxygen (and other elements). Inco acquired the patent, commenced production at its rolling mill in Huntington, WV, and thus established a milestone in the history of nickel plating. The industry now had a dependable anode with consistent, reproducible chemistry and physical properties and which corroded at high anode efficiency over a wide range of operating conditions and bath compositions. It was ideal in many applications, but caused roughness with some bright nickel solutions.
In bright nickel baths, anodes containing carbon and silicon were much better. But all were cast, and although some performed satisfactorily, large grain size and variations in the quality of castings made most far from ideal. With what may have been a mixture of foresight and luck, Inco once again stepped up to the need and introduced in the early 1930s a rolled anode containing carbon and silicon with traces of other elements. The anode performed ideally in bright nickel baths and in many other electrolytes. Quality of cast carbon anodes improved; these were offered by a few leading suppliers. The rolled carbon anode, however, remained for more than a quarter of a century the quintessential anode of the industry.
Its preeminence was shattered in 1962, when A.G. Sleeker and V.J. Cassiday revealed the use of anodes composed of titanium baskets filled with squares of electrolytic nickel to plate automobile bumpers58. Titanium baskets did not lessen the electrochemical deficiencies of electrolytic nickel. But they overcame the physical limitations. Baskets could be as long, as wide, and as thick as the plating tank and the work required, and to maintain a constant anode area, the plater had only to add more nickel squares to the baskets as the nickel corroded. Later that year, a group of platers met in Chicago to discuss plating with baskets and some of them, eager to save money, decided to try them. Use spread; the anode industry was never the same again.
Knowing the disadvantages of electrolytic nickel as an anode and realizing baskets were here to stay, Inco, in 1963, introduced a new electrolytic nickel containing just enough sulfur to enable it to corrode smoothly and efficiently over a broad range of conditions. The product proved to be even better electrochemically than the carbon anode. This was followed a few years later by another Inco innovation, the same excellent depolarized electrolytic nickel in a round, or button, shape with obvious advantages over the squares.
About 1980, both Falconbridge Nickel Co. and Inco introduced round forms of pure electrolytic nickel for those platers who preferred that type despite its deficiencies. The anode industry had come a long way since the days of Isaac Adams.
