Preparation of EMI shielding and corrosion-Resistant composite based on electroless Ni-Cu-P coated wood

Abstract

A simple electroless Ni-Cu-P plating process for preparing an EMI-shielding and corrosion-resistant wood-based composite has been developed. The effects of solution pH value on the metal deposition, surface resistivity, chemical composition, anti-corrosion properties, and crystal structure of the coatings were studied. The coatings were characterized using X-ray photoelectron spectroscopy, X-ray diffraction, and scanning electron microscopy. When the solution pH was increased from 8.5 to 10.0, the metal deposition increased and the surface resistivity decreased. Chemical composition indicated that the nickel deposition increased, whereas the opposite effect was obtained on copper and phosphorus elements with a pH increase from 9.0 to 10.0, and the crystal structure of the Ni-Cu-P coatings changed from an amorphous state to a microcrystalline one. Tafel curves of the Ni-Cu-P coatings prepared at pH 9.0 or 9.5 showed that they had excellent anti-corrosion properties in a 3.5 wt% NaCl solution. The morphology of the coating containing 69.86% Ni-7.65% Cu-22.49% P is superior to that with 75.99% Ni-6.60% Cu-17.41% P after corrosion tests. The plated birch veneers exhibited electromagnetic shielding effectiveness higher than 58 dB in frequencies ranging from 9 KHz to 1.5 GHz, and the coating firmly adhered to the wood surface.