Metal Finishing Guide Book

2011-2012 Surface Finishing Guidebook

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Table V. Troubleshooting Acid-Tin-Based Baths Problem Treeing Cause Low additive Low acid Roughness Organic contamination Solids in bath Metallic contamination Stannic tin Graininess Burning Streaking or pitting Poor throw Gassing Low additive Low tin Low acid Too high current density Low additive Low additive Low additive Low acid Low tin Too high current density Low additive Organic contamination Low tin Lack of adhesion Brittle deposits Dark deposit Low temperature Poor cleaning Organic contamination Low temperature Low additive Organic contamination Remedy Add additive. Increase acid. Carbon treat. Filter. Dummy bath. Filter and exclude air from bath. Add additive. Increase tin. Increase acid. Lower current density. Add additive. Add additive. Add additive. Increase acid. Increase tin. Lower current density. Add additive. Carbon treat. Increase tin. Increase temperature. Correct cleaning cycle. Carbon treat. Increase temperature. Add additive. Carbon treat. Table VI. Troubleshooting Lead-Based Baths Problem Treeing Cause Low lead Poor throw Roughness Low additive Low lead Low additive Metallic contamination Solids in bath Too high current density Low agitation Low additive Low acid Chloride/sulfate contamination cleaning cycle. Lack of adhesion Dark deposit Thin deposit Mossy deposit (ternary alloy only) Poor cleaning Organic contamination Low lead Too low current density Excess copper in bath Remedy Increase lead. Add additive. Increase lead. Add additive. Dummy the bath. Filter bath. Lower current density. Increase agitation. Add additive. Increase acid. Filter bath and check Correct cleaning cycle. Carbon treat. Increase lead. Increase current density. Analyze and adjust copper. 251

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