Atmospheric corrosion resistance of electroplated Ni/Ni–P/Au electronic contacts

Enhancing the corrosion resistance of Cu/Ni-P/Au electrical contacts by electropolymerized poly(methyl methacrylate)

“…The effect of electropolymerization cycles on the mass gain of samples is illustrated 3 in Figure 2. A strong increase of sample mass can be seen in the first 5 cycles, 4 followed by a slow mass increase between C5 to C50 with a quasi-constant slow rate 5 of deposition. This result is in good accordance with the small variation of the current 6 on CV curves in Figure 1 between C5 to C25.…”

“…Therefore, 1 Ni-P films have superior properties due to the lack of crystalline defects (such as 2 grain boundaries) that serve as preferential sites for diffusion of chemical species 3 and localized reactions like corrosion. The required thickness of Au is reported to be 4 drastically reduced when amorphous Ni-P films are used. The Au film is notably 5 thin due to its high cost; the total thickness of the Ni barrier layer and Au film 6 remains below 3 µm [3,4].…”

“…The required thickness of Au is reported to be 4 drastically reduced when amorphous Ni-P films are used. The Au film is notably 5 thin due to its high cost; the total thickness of the Ni barrier layer and Au film 6 remains below 3 µm [3,4]. 7 However, the porosity of thin films increases with decreasing the thickness.…”

“…7 However, the porosity of thin films increases with decreasing the thickness. Hence, 8 thin top Au films in electrical contacts are to some extent porous [4]. The pores act 9 as channels and deliver corrosive media to the under-layer [2].…”

“…Note that the intensity for Au is almost intact. The formation of an amorphous phase, 4 here PMMA, on the surface of metals increases the X-ray intensity at low diffraction 5 angles [38][39][40]. The intensity decrease of Cu and Ni can be attributed to the PMMA-6 filled pores.…”