Microstructure Optimization via Grain-Boundary Segregation to Enhance DC Bias Dielectric Performance of BaTiO₃...

Area of Science:

• Materials Science
• Ceramic Engineering
• Nanotechnology

Background:

• Multilayer ceramic capacitors (MLCCs) are vital electronic components.
• Enhancing capacitance requires thinner ceramic layers, posing challenges in grain size control and high electric field stability.
• Current MLCCs often rely on expensive rare-earth elements.

Purpose of the Study:

• To develop a cost-effective strategy for producing fine-grained BaTiO₃ for MLCCs.
• To investigate the effect of single-element additives (Fe³⁺, Ni²⁺) on grain growth suppression.
• To optimize BaTiO₃ microstructures for enhanced capacitance and reliability.

Main Methods:

• Utilized single-element additives (Fe³⁺, Ni²⁺) to control grain growth in BaTiO₃.
• Analyzed grain boundary segregation of additives.
• Sintered BaTiO₃ ceramics to achieve fine-grained microstructures.
• Characterized dielectric properties (permittivity, loss) and stability under high DC bias.

Main Results:

• Fe³⁺ and Ni²⁺ additives effectively suppressed grain growth by segregating at grain boundaries.
• Optimized BaTiO₃ samples achieved a stable high permittivity (≈10³), low dielectric loss, and improved reliability.
• Identified an ideal grain size of ≈200 nm for maximizing capacitance under high DC bias (> 4 V µm⁻¹).
• Developed fine-grained microstructures without rare-earth elements.

Conclusions:

• Single-element additives offer a viable, cost-effective method for controlling grain size in BaTiO₃.
• The optimized fine-grained BaTiO₃ exhibits excellent dielectric properties and stability for advanced MLCC applications.
• Reducing dielectric layer thickness to 200 nm is a promising avenue for future high-performance MLCCs.