Nickel coated on beech wood by electroless nickel coating: effects of complexing agent concentrations on nickel film properties

In order to obtain beech wood substrates with new functions as conductive materials and to develop their utilities in industrial fields, the technique of electroless nickel coating on the beech wood substrate was employed. The influence of complexing agent concentration [Na2EDTA·2H2O] on the nickel surface resistivity was studied. The process conditions were Ni(CH3COO)2·4H2O 0.103 mol/L, CH3CHOCOOH 18.18 mL/L, N2H5OH 54.54 mL/L, NaOH 0.193 mol/L, pH value of 9.5, temperature of 75 °C, and the complexing agent concentration varied between 0.012 and 0.061 mol/L. By means of XRD, EDXRF, and SEM, the chemical composition and morphology of the prepared films were investigated. The results showed that when the complexing agent concentration increased from 0.012 to 0.061 mol/L in the electroless nickel coating baths, the gained nickel mass on the beech wood substrate decreased from 17.04 to 9.03 mg/cm2, the nickel crystallite sizes reduced from 16.1 to 1.41 nm and the electric measurements demonstrated that the nickel surface resistivity rose from 0.004 to 192.16 kΩ/cm2.