Metal Finishing Guide Book

2011-2012 Surface Finishing Guidebook

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Page 272 of 707

Table II. Bath Parameters Wetting agents, refining agents or carrier Brightener Temperaturea a Acid Chloride Zinc 2.0–5.0% vol./vol. 0.05–0.2% vol./vol. 60–130°F (15–55°C)1 Alkaline Non-cyanide Zinc 1.0–3.0% vol./vol. 0.05–0.2% vol./vol. 60–110°F (15–48°C) Cyanide Zinc Not applicable 0.2–0.5% vol./vol. 60–110O Positive and negative effects are observed when a bath is operated above room temperature (75°F): • Because of the solution evaporation, bath buildup problems can be minimized or eliminated. • At higher temperatures, higher conductivity means less power consumption. • Plating speed is increased at higher temperatures. This means less plating time is required. • Operating at higher temperatures means savings in refrigeration cost. • At elevated temperatures, brightener consumption may be higher than at room temperature. • The solubility of organic additives can become a negative factor. 1 New high-temperature chloride zinc systems for barrel work have reduced plating time 10–50% and increased production 30–100%. SAFETY CONCERNS The characteristics of zinc plating baths deserve consideration due to possible safe- ty hazards. While acid chloride zinc and alkaline non-cyanide zinc result in no tox- icity to humans, cyanide zinc is highly poisonous. Platers should remember that the formulations of acid chloride zinc baths make them corrosive to equipment. Alkaline non-cyanide and cyanide baths are noncorrosive to equipment. Exposure to the chemicals in alkaline non-cyanide zinc and cyanide zinc baths can be corrosive to living tissue, whereas acid chloride zinc appears to have little ■ BRASS ■ COPPER ■ BRONZE ■ F (15–43°C) Will Make You Look Good Our PLATING ANODES world of Trivalent Chromates. We're re-coloring the Add value to your plating anodes purchase with the highest quality, most cost-effective product. We offer a large inventory of metals and shapes. Belmont's renowned customer service saves you time and money. SpectraMATE® YOUR ZINC PARTS FOR 250 HOURS OF CORROSION PROTECTION WITHOUT A TOPCOAT ® SpectraMATE® is the new generation trivalent (hex- chrome-free) thick-film chromate. It exceeds automotive standards with 250 hours of consistent corrosion-resistance – at ambient temperatures, lower concentrations, and a wide operating window. VISIT Tel. (718) 342-4900 ■ FAX: (718) 342-0175 ■ CADMIUM ■ NICKEL ■ ZINC ■ SpectraMATE your zinc parts for the most consistent high-corrosion trivalent chromate protection available. Contact us at 330/225-3200 or 271 ■ OV AL ■ ROLLED ■ SPECIAL SHAPES ■ FLAT TOP ■ ■ LEAD ■ SOLDER ■ TIN ■ BALL ■ CAST FLA T ■

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