Bio-inspired material is 10x stronger than ceramic
Researchers have copied the structure of nacre – a strong, iridescent material found on the inside of mollusk shells – to create a material that's almost 10 times stronger than conventional ceramics.
Nacre, also known as mother-of-pearl, is made up of layers of brittle platelets and thin layers of elastic biopolymers. The brickwork-like arrangement of the platelets inhibits crack propagation and greatly increases toughness – hence why the researchers decided to replicate it.
As a base ingredient, the team from the Laboratoire de Synthèse et Fonctionnalisation des Céramiques in Paris used a ceramic powder made up of microscopic alumina platelets.
To obtain the layered mother-of-pearl structure, they suspended this powder in water. The colloidal suspension was then frozen to obtain controlled ice crystal growth, causing the alumina to self-assemble in the form of stacks of platelets.
The final material was subsequently obtained from a high temperature densification step.
In lab tests, the researchers found that cracks had great difficulty spreading through the ceramic because they had to move around the alumina 'bricks' one by one to propagate.
The material was also able to retain its properties at temperatures of 600°C, which means it could find application in industry and reduce the weight or size of ceramic elements in motors and energy generation devices.
What's more, the researchers say the production process should work with any type of ceramic powder and can be easily scaled up.
