Electrical conduction mechanisms in piezoelectric ceramics under harsh operating conditions

Deyi Zheng, Jonathan Swingler, Paul M. Weaver

Research output: Contribution to journalArticle

Abstract

Piezoelectric ceramics are widely used in industry for sensor and actuator applications. Under an applied electric field over a long duration, the conductivity of the ceramic increases resulting in leakage currents and increased power consumption. This process is accelerated by harsh environments and operating conditions such as high temperature, high humidity and high electric field. In this study, a piezoelectric ceramic was stressed by exposure to high relative humidity, at an elevated temperature, with a continuously applied d.c. electric bias field. Periodically during the test, the bias field was removed and a low frequency a.c. electrical cycle applied, during which current and voltage were measured. Results show that the conductivity is both time and voltage dependent and indicative of a complex breakdown process in the ceramic. The breakdown field strength was observed to vary only slightly during the exposure to humidity and d.c. bias despite large increases in conductivity. The reestablishment of the conduction process on re-application of the d.c. bias field was also studied. Whilst these results are specific to the piezoelectric material system studied, the mechanisms and insights into the interaction of electrodes with a ceramic material under conditions of high humidity and high electric field are likely to have much wider relevance for electro-ceramics in general, including technologically important materials such
Original languageEnglish
Pages (from-to)19-24
JournalSensors and Actuators A: Physical
Volume167
Issue number1
DOIs
Publication statusPublished - 2011

Keywords

  • Piezoelectric ceramics
  • Electrical conduction mechanisms
  • Harsh operating conditions
  • Electrical breakdown

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