The electrical resistivity of metal fiber-filled polymer composite always increases during injection molding process because the conductive fibers were easily broken down to shorter under the action of high shear stress. In order to decrease electrical resistivity of the molding, we investigated the microstructure at different layers within the molding made from stainless steel fiber-filled polypropylene and measured their resistivities. High resistive zone mediate resistive zone and low resistive zone were found within the molding. The results showed that the high resistivity zone located at the skin area of the molding where average length of filled fibers was less than other zones, and the smallest resistive zone located at the core area where most fibers preserved large ratio of length to diameter and oriented along flowing direction of the melt, and the sub-skin zone is mediate resistive zone.

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