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and 0.25% silicon; and cast bars containing approximately 0.25% carbon and 0.25% silicon. Soluble auxiliary anodes are generally carbon- and silicon-bearing small-diameter rods. With the exception of the sulfur-bearing materials, nickel anodes require the presence of chloride ion in the plating bath to dissolve efficiently. Rolled or cast carbon-bearing materials are used up to a pH of 4.5, and oxygen-bearing, rolled depolarized anode bars can be used above a pH of 4.5 when chlorides are present in solution. References 1. Brown, H. and B.B. Knapp, "Nickel," in Lowenheim, F.A. (Ed.), Modern Electroplating, 3rd Ed., pp. 287-341; John Wiley, New York; 1974 2. American Society for Testing and Materials, "Standard Practice for Use of Copper and Nickel Electroplating Solutions for Electroforming," in Annual Book of ASTM Standards, Section 2, Vol. 02.05, B 503-69; ASTM, Philadelphia; 1993 236