Hybrid sintering of CNT/PZT ceramics using microwave oven

Abstract

Piezoelectric materials play a major role in a variety of applications such as sensing, actuation and energy harvesting. Lead Zirconate Titanate (PZT) is a commonly used piezoelectric material because of its superior piezoelectric properties. One of the key elements to optimize the manufacturing process of this group of piezoelectric materials is minimizing the processing time and energy required to prepare ceramic parts. Among the production steps, the sintering process needs the most time and consumes the most energy. In this study, a rapid sintering method of bulk PZT elements is proposed based on microwaves. Carbon nanotubes (CNTs) are added to the material as an absorption aid. The effects of different sintering temperatures, microwave (MW) power and CNT weight fraction on the grain size, physical, mechanical and piezoelectric properties are investigated. The results show that higher MW powers lead to smaller grain sizes, higher mechanical properties but lower densities and electromechanical properties. The introduction of CNTs to the PZT material results in higher heating rates at the initial portion of the sintering process as well as smaller and more uniform grains while decreasing the density. The ceramic parts with 1 wt% CNTs concentration have the highest piezoelectric coefficient after sintering and poling. Generally, the proposed method is more environmentally friendly than the conventional method because not only does it require a lower processing time and energy, but also it leads to the formation of a single-phase perovskite structure without the need for additional amounts of lead.