Scalable and shapable nacre-like ceramic-metal composites based on deformable microspheres

Area of Science:

• Materials Science
• Ceramics Engineering
• Biomimetics

Background:

• Natural nacre displays remarkable fracture toughness and strength due to its hierarchical 'brick-and-mortar' structure.
• Biomimetic ceramic composites inspired by nacre face limitations in size, fabrication efficiency, and shape flexibility.
• Developing scalable and versatile nacre-mimetic materials is crucial for advanced applications.

Purpose of the Study:

• To fabricate nacre-like ceramic-metal composites with a 'brick-and-mortar' architecture.
• To overcome limitations in size, production efficiency, and shape molding for biomimetic ceramics.
• To achieve simultaneous high strength and fracture toughness in the developed composites.

Main Methods:

• Deformable alumina microspheres coated with nickel salt were assembled into green bodies.
• Hot-pressing sintering induced microsphere flattening into platelets, forming a 'brick-and-mortar' structure with nickel interlayers.
• Microsphere size was tuned to optimize microstructure and mechanical properties.

Main Results:

• Successfully fabricated nacre-like alumina-nickel composites with a hierarchical 'brick-and-mortar' structure.
• Achieved high flexural strength (386 MPa at room temp, 286.86 MPa at 600°C).
• Demonstrated high fracture toughness (12.76 MPa·m^1/2 at room temp, 12.99 MPa·m^1/2 at 600°C) simultaneously with high strength.

Conclusions:

• The developed method allows for feasible mass production and all-in-one molding of nacre-like composites.
• The strategy enables control over shape, size, and raw materials for tailored ceramic-metal composites.
• This approach offers a promising pathway for creating high-performance, nacre-inspired structural materials.