Metal Finishing Guide Book


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Bath Type pH electrode AA, ICP, spectrophotometry Ammonia chloride NA Ammonia hydroxide pH electrode Pd metal AA, ICP, spectrophotometry Ammonia chloride NA Hydrochloric acid pH titration Lead metal AA, ICP, spectrophotometry Nickel metal AA, ICP Ammonia chloride NA Ammonia hydroxide Pd-Ni alloy (80/20) Pd-Co alloy (80/20) NA Pd metal Palladium chloride PdCl2 AA, ICP, spectrophotometry Ammonia sulfamate Ammonia hydroxide Palladosamine chloride Pd(NH3)4Cl2 Analytical Method Pd metal P-salt/sulfamate Pd(NH3)2 (NO2)2 salt Parameters pH electrode Table 5: Analysis of Pd, Pd-Ni, and Pd-Co Baths ANALYTICAL TECHNIQUES It is important to review the flow sheet of a given plating process (rack, barrel, reel to reel) and understand the sequence of the operation. This guides the operator to prepare for a safe start by analyzing the plating baths needed in the process. Most job shops use traditional wet methods. The commercial use of instrumental techniques is limited due to complex operations, maintenance, frequent calibrations, personnel training, and the expense of initial investment. The workload of a plating plant can justify the use of any instrumental technique, such as AA, ICP, chromatographic techniques, or any dedicated electrochemical method. The following outline may be helpful in understanding their relationship. a) Photometric methods: 1. Spectrophotometry 2. Colorimetry (measures color intensity at a given wavelength) 3. Turbidimetry (measurement of radiation passing through suspension) 4. Nephelometry (measurement of radiations scattered from suspension) All methods are based upon the absorption of light. b) Spectrophotometric methods are based on emission of light. For example: 1. Flame photometry 2. Flame spectroscopy 3. Mass spectrometry (MS) 514

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