Lead-Free Piezoelectric Element Mixed Crystal Structure
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lead-free piezoelectric materials used in liquid ejecting heads and sensors face challenges with high leak current and insufficient displacement, limiting their effectiveness compared to lead-based materials.
Innovation Solution
A piezoelectric element comprising a mixed crystal structure with complex oxides having rhombohedral and tetragonal perovskite structures, including BiFeMnO3, (Bi0.5K0.5)TiO3, and Bi(Mg0.5Ti0.5)O3, which suppresses Fe2+ generation, utilizing lattice distortion and morphotropic phase boundary effects for enhanced piezoelectric displacement and reduced leak current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If lead-free piezoelectric material is used, then environmental friendliness is improved, but leak current increases and displacement amount decreases
Solution Approach 1:
The invention uses a composite piezoelectric material combining multiple perovskite structures (rhombohedral BiFeO3 and tetragonal BaTiO3) in a single system. This composite approach leverages the advantages of each component: BiFeO3 provides high piezoelectric potential, while BaTiO3 contributes to structural stability and reduced leakage. The synergistic combination achieves both environmental friendliness and improved electrical characteristics compared to single-phase lead-free materials.
Solution Approach 2:
The invention optimizes the compositional parameters of the piezoelectric material by controlling the ratio of rhombohedral to tetragonal perovskite structures. By adjusting the proportion of BiFeO3 and BaTiO3 phases and controlling Fe2+ content through parameter optimization, the material achieves reduced leak current and enhanced displacement characteristics while maintaining lead-free composition.
2Reliability
If lead-based piezoelectric material (PZT) is used, then displacement amount and piezoelectric characteristics are improved, but environmental harm increases
Solution Approach 1:
The invention replaces expensive and environmentally harmful lead-based materials with lead-free alternatives. While early lead-free materials had performance limitations, the optimized composite lead-free material now provides comparable functionality without the environmental burden, effectively making the system more sustainable and environmentally acceptable.
Solution Approach 2:
Through precise control of compositional parameters including the ratio of rhombohedral to tetragonal phases, doping concentrations, and sintering conditions, the invention achieves piezoelectric performance in lead-free materials that approaches or matches traditional PZT, thereby eliminating the need for lead-based materials.
3Reliability
If substitution elements are introduced to improve leakage characteristics, then leak current is reduced, but material complexity increases
Solution Approach 1:
The invention manages material complexity by focusing on optimizing a limited set of key parameters: the ratio of rhombohedral BiFeO3 to tetragonal BaTiO3 phases, and the suppression of Fe2+ generation. This targeted parameter optimization approach achieves improved leakage characteristics without requiring complex multi-element substitutions, thereby controlling material complexity while enhancing performance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution achieves high piezoelectric displacement and low leak current, while being environmentally friendly by eliminating lead, thus improving the performance and reducing environmental impact.
Implementation Method 1
a piezoelectric layer made of a piezoelectric material having an electromechanical conversion function
Implementation Method 2
this vibrating plate is deformed by a piezoelectric element to pressurize an ink in the pressure generation chamber
Data Source
AI summary
A piezoelectric element 300 includes a first electrode 60, a piezoelectric layer 70 which is provided on the first electrode, and a second electrode 80 which is provided on the piezoelectric layer, and the piezoelectric layer is made of a piezoelectric material expressed as a mixed crystal including a first component formed of a complex oxide containing Bi and Fe and having a rhombohedral perovskite structure and a complex oxide containing Ba and Ti and having a tetragonal perovskite structure, a second component formed of a complex oxide containing Bi, K, and Ti and having a tetragonal perovskite structure, and a third component formed of a complex oxide containing Bi, Mg, and Ti and having a rhombohedral perovskite structure.