A new electroless Ni plating procedure of iodine-treated aramid fiber

摘要

A new, durable, etchant- and tin-free cataly-zation process was studied for electroless nickel metallization of aramid fiber via iodine pretreatment. Firstly, iodine components were selectively doped onto the inner part of the fiber using vapor iodine exposure followed by treatment with a tin-free acidic palladium chloride solution to form palladium iodide (PdI_2) on the fiber surface. After subsequent reduction of PdI_2 into metal palladium (Pd), electroless plating was carried out. A uniform Ni plating layer was formed on the fiber surface, which exhibited high durability against resistance tests of ultrasonic exposure, tape peel-off, and corrosion in NaCl solution. Here, Pd particles that formed at the inner part near the fiber surface functioned as an anchor of the plated layer as well as a catalyst of electroless plating. Investigation of the plate bath composition shows that the use of anionic surfactant enhances the adhesion of the plated layer with fiber matrix, while a reducing agent in the plate bath reduces the smoothness of the plated surface. Also, the plate bath pH and the temperature of the plating solution control the layer deposition rate noticeably more than does the plating time. The proposed method retained good tensile strength in the plated fiber. Ni-plated aramid fiber exhibited durable electrical conductivity and magnetic properties.