Electroless plating of nickel-cobalt-phosphor alloy on surface of glass fiber

Nickel-cobalt-phosphor (Ni-Co-P) alloy was deposited on the surface of glass fiber by electroless plating from a bath using ammonium sulfate as a buffer agent, hypophosphite as a reducing agent, and nickel sulfate and cobalt sulfate as the main salts. The deposits were characterized using a scanning electron microscope, energy dispersive X-ray spectroscopy, differential scanning calorimetry, and X-ray diffraction. It is found that the presence of ternary complexing agents in the bath is able to improve the stability of the bath and the morphology of the deposits. Comprehensively considering the deposition rate, bath stability and resistivity, mole ratios of n (H₂PO₂^-) /n(Ni²⁺+Co²⁺)=2-2.5 were chosen. Electroless plating of Ni-Co-P alloy on the surface of glass fiber has good heat stability. The suitable working temperature range is lower than 180°C.The deposits have a typical amorphous structure when the mass fraction of phosphorus in deposits ranges from 8.1% to 23.6%. The crystallization behavior of Ni_63.2Co_16.5P_20.3 was studied. The crystallization processes of the film are as follows: Ni→Ni+Ni₅P₂ →Ni+Ni₅P₂ +Ni₁₂P₅+Ni₃P →Ni+Ni₁₂P₅+Ni₃P. The alloy as plated is a soft magnetic material. There is almost no magnetic loss of the conducting glass fibers, but the dielectric loss of the conducting glass fibers is extremely large, the plating is a typical dielectric loss material.