One-step fabrication of thermal sprayed polymer coating on metals

This study presents the polymer coating onto metal-based structures by the thermal spray process. The deposition of polymers onto metal substrate has been developed by controlling the temperature in conventional thermal spray process. Properties of final polymer coating are investigated, such as microstructural, crystallization, mechanical, friction and corrosion properties. The objective of this is to deposit a polymer coating by controlling temperature in conventional thermal spray process and evaluate the coating properties for specific applications such as polymer coating on vacuum pump screws as abrasion resistant coating and on Kevlar fabric to provide strength for bullet proof soft armor vest for defense application. This study reports that as-sprayed coating can be used without post processing like annealing and filing. As-sprayed PEEK coating has a considerable hardness and adhesion strength found to be 17 5 HV, 16 3.0 MPa, respectively. However, post annealing treatment may introduce further improvements in wear and friction resistant properties of the final polymer coating system. The microhardness value has increased from 17 HV to 29 HV in average. The annealed semi-crystalline coatings exhibit the slightly lower friction coefficient than amorphous coating (as-sprayed); 0.31 in average versus 0.36. The wear rate of annealed coating is lower than the as-sprayed coating, decreased by approx 50% (10.5 in average versus 20.5 x 10(- 6) mm(3) N-1 m(-1)). The PEEK coating protects the base metal against corrosion and life against corrosion is found to be 25.4 mu m.y(-1); 81.75% efficiency in reduction of corrosion with respect to steel exposed in 5% NaCl solution.