( in the keyboard of a PC-compatible comp...)Characterizing galvanizing baths

Experimental Procedures
Samples obtained for analysis were divided into six segments. Electron-galvanizing bath (EV) was a sample of the current bath causing problems for the operator. Sample A is the plating bath that would compose the ideal EV bath. Sample B is a bath that contains 0.6 mL of starter and 1.5 mL of brightener. Sample C is a bath that contains 2 mL of starter and 0.5 mL of brightener. Starter and brightener stock samples were obtained for comparison.

Results and Discussion
The six samples were characterized by their excitation and emission spectra shown in Figures 1 through 4. The fluorescence spectra could offer a possible method for correctly mixing the appropriate concentrations or proportion of starter and brightener solutions in the EV bath. For the coating process to work, a constant level of starter and brightener is necessary.

Figure 1 illustrates that sample A was 5 10⁵ counts lower in fluorescence intensity than the EV bath. Sample C was 10⁶ counts higher in intensity than the EV bath. Therefore, a component in sample C must have been the cause of the greater intensity. Sample C contained the largest amount of starter solution, the smallest volume of brightener solution. This indicates that the actual EV bath contained too much starter solution, based on the difference in fluorescence intensities.

The data were fitted to the following linear equation:

I_f =A [Brightener] +B [Starter] +C

where A, B, and C are constants, [Brightener] is the concentration of brightener, [Starter] is the concentration of starter, and I_f is the observed intensity of fluorescence. An empirical linear relationship thus was established between the fluorescence intensity and ra
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