Effect of the Applied Pressure on the Physical and Chemical Properties of Nickel Films Prepared by Electroless Plating on Beech Wood

Abstract

Nickel films were deposited on beech wood substrates using the electroless plating method, and the effect of applied mechanical pressures (2, 4, 6, and 8 kN/cm2) on their structural, morphological, wetting, and electrical properties was systematically investigated. Nickel-coated wood specimens were subjected to uniaxial pressures for 3 s, followed by characterization using scanning electron microscopy (SEM) with energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD), contact-angle (CA) measurements, and current–voltage (I–V) analysis. SEM revealed surface openings of approximately 2–4 μm at 2 kN/cm2, which progressively narrowed with increasing pressure and were nearly absent at 8 kN/cm2. Cross-sectional SEM-EDS confirmed Ni penetration into the porous wood structure, with the greatest apparent penetration depth observed at 6 kN/cm2. XRD identified face-centered-cubic Ni with a preferential (111) orientation, while Williamson-Hall analysis indicated pressure-dependent variations in crystallite size and lattice microstrain. The wetting behavior exhibited a pressure-dependent response, with the highest initial contact angle observed at 6 kN/cm2, followed by a decrease at 8 kN/cm2 consistent with increased water penetration associated with pressure-induced surface and interfacial damage. All samples exhibited approximately linear I–V characteristics (R2 > 0.99), with the highest electrical response observed at 6 kN/cm2 and a subsequent decline at 8 kN/cm2. Overall, the results demonstrate a pressure-dependent balance between compaction of the nickel conductive network at moderate pressures and mechanical degradation under excessive compression, providing a basis for pressure-controlled design of functional conductive Ni/wood interfaces.