Properties of BaTiO3/Al2O3 Laminate Structure by Nanoindentation

Abstract

The proposed material design of BaTiO3/Al2O3/ZrO2 laminate structure predetermined for energy harvesters taking advantage of residual stresses developed during processing was prepared by electrophoretic deposition. The main aim of developed residual stresses is to enhance overall mechanical reliability of piezoceramic functional layers and/or to enhance piezoelectric effects acting in the laminate. The concept of co-sintered BaTiO3 piezo ceramic functional layers with protective ZrO2 and Al2O3 layers is based on strongly bonded layers. In this contribution will be described particular behaviour of the specific material configuration BaTiO3/Al2O3 laminate where an interface interlayer among other effects was formed. The influence of sintering conditions on the microstructure development of the laminate as well as the formation of the interlayer was investigated. The relationship between observed microstructural changes and resulting mechanical properties as hardness and indentation elastic modulus was analyzed by means of nanoindentation technique. The cracks propagation through the individual layers and specific formed interfaces were observed and analyzed. The crack deflection due to the presence of developed residual stresses during the cooling stage of sintering as well as the consequence of microstructural changes on mechanical properties was confirmed.The proposed material design of BaTiO3/Al2O3/ZrO2 laminate structure predetermined for energy harvesters taking advantage of residual stresses developed during processing was prepared by electrophoretic deposition. The main aim of developed residual stresses is to enhance overall mechanical reliability of piezoceramic functional layers and/or to enhance piezoelectric effects acting in the laminate. The concept of co-sintered BaTiO3 piezo ceramic functional layers with protective ZrO2 and Al2O3 layers is based on strongly bonded layers. In this contribution will be described particular behaviour of the specific material configuration BaTiO3/Al2O3 laminate where an interface interlayer among other effects was formed. The influence of sintering conditions on the microstructure development of the laminate as well as the formation of the interlayer was investigated. The relationship between observed microstructural changes and resulting mechanical properties as hardness and indentation elastic modulus was analyzed by means of nanoindentation technique. The cracks propagation through the individual layers and specific formed interfaces were observed and analyzed. The crack deflection due to the presence of developed residual stresses during the cooling stage of sintering as well as the consequence of microstructural changes on mechanical properties was confirmed.