Influence of processing conditions on nanoindentation properties of spark plasma sintered ptfe

Abstract

The Spark Plasma Sintering (SPS) is considered as fast sintering route using self-heating action from inside the powder similar to microwave sintering and self-propagating high temperature. High sintering rate, low temperature processing, ease of operation and accurate control of sintering energy are the major advantages of this non-melting technique with regard to classical methods. The aim of this investigation is to take benefit from the advantages offered by the SPS process in order to sinter the polytetrafluoroethylene (PTFE) polymer materials from PTFE powder particles. The effect of the process’s parameters, namely the sintering temperature and heating rate, on the nanoindentation deformation is explored at room temperature. Empirical data on depth-dependent hardness are confronted to some theoretical models with a special focus on the apparent surface stress changes with the indentation depth. Furthermore, the obtained results are compared to the macro-behavior deduced from tensile and bending properties in order to assess the change in both surface and bulk deformations of the SPSed samples and according to the processing parameters.