Reducing Sintering Temperature While Optimizing Electrical Properties of BCZT-Based Lead-Free Ceramics by Adding MnO₂...

Area of Science:

• Materials Science
• Solid State Chemistry
• Ceramic Engineering

Background:

• Lead-free piezoelectric ceramics are crucial for sustainable electronic devices.
• Reducing sintering temperatures is key to cost-effective and environmentally friendly manufacturing.
• Manganese dioxide (MnO2) is explored as a potential sintering aid.

Purpose of the Study:

• To investigate the effect of MnO2 doping on the properties of lead-free piezoelectric ceramics.
• To reduce the sintering temperature of [(Ba0.85Ca0.15)0.999(Dy0.5Tb0.5)0.001](Zr0.1Ti0.9)O3 (BCDTZT).
• To optimize MnO2 content for improved phase structure, sintering behavior, and electrical properties.

Main Methods:

• Synthesis of BCDTZT ceramics with varying MnO2 content (x = 0.05–3 mol%).
• Analysis of phase structure, sintering behavior, and density using X-ray diffraction and density measurements.
• Evaluation of electrical properties including dielectric constant, piezoelectric constant (d33), strain, and hysteresis.
• Calculation of activation energy to understand conductivity mechanisms.

Main Results:

• MnO2 addition successfully reduced the optimal sintering temperature from 1515 °C to 1425 °C.
• Ceramic density increased with MnO2 doping, reaching a maximum of 5.38 g/cm³ at 0.8 mol%.
• 0.4 mol% MnO2 doping yielded optimal performance: dielectric constant of 12,817, piezoelectric constant of 330 pC/N, strain of 0.118%, and low hysteresis (2.66%).
• High-temperature conductivity was dominated by oxygen vacancies.

Conclusions:

• MnO2 acts as an effective sintering aid, lowering processing temperatures for BCDTZT ceramics.
• Optimized MnO2 doping significantly enhances piezoelectric properties and reduces strain hysteresis.
• These improved lead-free piezoelectric ceramics hold promise for low electric field sensors and actuators.