This paper mainly studies the measuring method for the thickness of plating layer ofthe eddy-current sensor in the case of the multi-frequency and multi-parameters.

The fiber is firstly coated with a thin copper or nickel plate with electroless plating method. Then, a thicker nickel plate is coated on the surface of the conductive layer.

A method for autocatalytic plating of silver metal directly onto a silicon surface without the need for an intervening layer of metal is also disclosed.