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AUGUST 2018 I PCB007 MAGAZINE 61 and nickel thickness. This was followed by electroless non-phos palladium. The coupons' dwell time in the palladium bath was 1, 2, 4, 6, 8, and 10 minutes, giving rise to thickness that varied from 2–10 µin (0.05–0.25 µm) of pal- ladium. All six samples were then immersed into the immersion gold bath for 30 minutes at 180°F. The holes from each coupon were then cross-sectioned. Using the SEM, twenty corners were evaluated for nickel corrosion at 5000 and 1000X. Figure 6 is a graphic presentation of the data from Table 4. The data shows that the gold thickness at the lower palladium thickness was as high as 3.2 µin (0.06 µm) and continued to diminish as the thickness of the palladium in- Figure 2: Chart of phos-palladium and gold thicknesses vs. time in the palladium bath. Figure 3: Nickel corrosion at 2 µin (0.05 µm) of phos palladium. Corrosion was extensive and shallow. Figure 4: Ni corrosion at 4.8 µin (0.12 µm) of phos palladium. Few intermittent deep corrosion spikes. Figure 5: No corrosion at 8.8 µin (0.22 µm) of phos palladium. No corrosion was found. Table 4: Thickness of the different coupons for Test #2 with non-phos palladium.