Metal Finishing Guide Book

2011-2012 Surface Finishing Guidebook

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Sample 0 1 2 3 4 5 Ni-Sulphamate HS [10 A/dm2 ] 1.5 µm 1.5 µm 1.5 µm 1.5 µm 1.5 µm 1.5 µm Aurocor SC [µm] 0.3 0.3 0.3 0.3 0.3 0.3 Table 2: Part of the Sample Matrix Highlighting the Benchmark Products Figure 7: Stable contact resistance values before (red) and after (orange) an 8-hour pressure-cooker test. • <0.05 mm • 0.05–0.12 mm • 0.12–0.4 mm • >0.4 mm For each test specimen, a target area of 36 mm2 was used for each set of measurements. The process sequence used to prepare the samples was as per Figure 5. A total of 200 samples with a target gold thickness 0.3 µm were prepared and examined alongside samples treated with commercially available corrosion inhibitors (Benchmarks 1–4). Table 2 highlights a small fragment of the exper- imental matrix used. After being subjected to 2 hours of NAV testing, all samples were catego- rized by calculating and evaluating the pore count per corroded surface area. Figure 6 compares the calculated corrosion area of the samples. CONTACT RESISTANCE MEASUREMENT Extensive measurements establish that treatment with Betatec post-dip does not cause an increase in contact resistance. The parameters: I = 10 mA, U = 20 mV, F = 5 cN were used to satisfy the EN IEC 512 standard. The mean value of 30 mea- surements was used for each test sample. 151 below that used in previous studies). Samples removed from the chamber were oven-dried at 80°C prior to pore examina- tion, which was undertaken using a micro- scope together with Aquinto a4i docu/analysis software. Calculations involved pore count per area and individual pore diameter, providing an overall % cor- rosion area in accordance with the ASTM specification. Pores were size-categorized as follows: Post-treatment None Benchmark 1 Benchmark 2 Benchmark 3 Benchmark 4 Betatec

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