Polymer injection is an effective technique for increasing oil production in the later stage of petroleum exploitation. The pumps used typically incorporate ceramic plungers because they do not produce metal ions which tend to decrease polymer viscosity. This paper compares the performance of plasma sprayed and sintered alumina plungers and includes the results of stress analysis using finite elements and field testing. Under real working conditions, plasma sprayed plungers achieved an average lifetime of 12,000 hours, approximately double that of their sintered ceramic counterparts.