Effects of process parameters on the synthesis of palladium membranes

In this study, palladium film plating was carried out on porous glass supports using the electroless plating technique. This technique was applied to study the effects of bath temperature and reducing agent concentration on the amount and the structure of palladium plated. Hydrazine concentration was fixed at 10 ml/L in the baths using 1 M hydrazine solution while the temperature was changed between 25 and 50 °C. The total mass gain and Pd/Si ratio (wt/wt%) on the surface were obtained as 7.76 mg/cm2 and 68.7 in a bath temperature of 35 °C, respectively. With the help of LM microscope analysis, thickness of the membrane prepared at this temperature was determined as 31 μm. In the studies in which the bath temperature was examined as a parameter, the minimum total mass gain was obtained in a plating bath temperature of 43 °C. In the second part of this study, in order to study the concentration effect of hydrazine, hydrazine concentration was increased to 15 and 20 ml/L at a bath temperature of 43 °C. It was shown that as a result of increasing the hydrazine concentration from 10 ml/L to 15 ml/L, total mass gain increased more than twice and a denser plating was obtained. On the contrary to expectations, a result less successful than in the study of 10 ml/L concentration was obtained through increasing hydrazine concentration to 20 ml/L. This study showed that bath temperature of 25 °C was too low to carry out effectively autocatalytic reaction on the activated surface. Plating bath decomposed in plating studies performed at 43 °C and 50 °C. In the studies where hydrazine concentrations were examined as a parameter, it was observed that the stability of the bath could not be maintained in each of the three baths throughout the plating time. The highest decomposition rate was also predicted for the study carried out at a hydrazine concentration of 20 ml/L. Decomposition seen at high temperatures and high hydrazine concentrations was explained as a consequence of insufficient EDTA concentrations in plating baths.