Deposition of a heavier coating requires more careful attention to process control to prevent nodules and pitting. Electroless nickel plating is sensitive to deficiencies such as pit, pinhole and nodules. These defects are generally caused by the bath ingredients and operating conditions. This study specifically examined that the defects free electroless Ni-P deposits for heavy coating. Results of our investigation show that selection of complexing agent, elimination of insoluble particles from the plating solution using fine filtration, selection of pH adjustor and operating conditions are critical factors to avoid these defects.
We investigated electroless aluminum plating using AlCl3-1-ethyl-3-methylimidazolium chloride (AlCl3-EMIC) ionic liquid containing diisobutyl aluminum hydride (DIBAH) and BiCl3. The plating film was analyzed using X-ray diffraction and scanning electron microscopy. The aluminum films prepared with BiCl3 were smoother than those prepared without BiCl3. Furthermore, the plating bath stability was improved by addition of BiCl3.
The effects on cell performance of Nafion® content in 1 mg/cm2 Pt with a Pt and carbon mixture containing 50 wt.% Pt (50 wt.%Pt/C-1 mgPt/cm2) catalyst layers were studied under several humidified operating conditions at 80°C and 1 atm. The optimum Nafion® content for these conditions was 28-32 wt.% (0.76-0.95 mg/cm2). The value obtained using the 50 wt.%Pt/C catalyst was compared with reported values obtained using 20 wt.%Pt/C or 20 wt.%PtCr/C catalyst. The catalyst layer’s activation polarization with insufficient Nafion® decreases concomitantly with increased humidity, but that of a layer with excessive Nafion® increases with increased humidity.