Friday, August 11, 2017

A new featherweight, flame-resistant and super-elastic metamaterial from Purdue Uniuversity

Purdue University reports: WEST LAFAYETTE, Ind. — A new featherweight, flame-resistant and super-elastic metamaterial has been shown to combine high strength with electrical conductivity and thermal insulation, suggesting potential applications from buildings to aerospace.


A new composite material combines ultra-lightweight with flame-resistance, super-elasticity and other attributes that could make it ideal for various applications. Here, the material is viewed with a scanning electron microscope, while its flame resistance is put to the test. (Purdue University photo)

[From the abstract, Adv. Mater., DOI: 10.1002/adma.201605506] "A ceramic/graphene metamaterial (GCM) with microstructure-derived superelasticity and structural robustness is achieved by designing hierarchical honeycomb microstructures, which are composited with two brittle constituents (graphene and ceramic) assembled in multi-nanolayer cellular walls. Attributed to the designed microstructure, well-interconnected scaffolds, chemically bonded interface, and coupled strengthening effect between the graphene framework and the nanolayers of the Al2O3 ceramic (NAC), the GCM demonstrates a sequence of multifunctional properties simultaneously that have not been reported for ceramics and ceramics–matrix–composite structures, such as flyweight density, 80% reversible compressibility, high fatigue resistance, high electrical conductivity, and excellent thermal-insulation/flame-retardant performance simultaneously."
 
Findings were detailed in a research paper published on May 29 in the journal Advanced Materials. The paper was a collaboration between Purdue, Lanzhou University and the Harbin Institute of Technology, both in China, and the U.S. Air Force Research Laboratory. A research highlight about the work appeared in the journal Nature Research Materials and is available at https://www.nature.com/articles/natrevmats201744.pdf. A YouTube video (below) about the work is available at https://youtu.be/PVd-eS_KMlU.

The ALD process of the nanolayer Al2O3 ceramic (NAC) were performed in an Utratech Fiji F200 (now Veeco CNT) ALD system at 250 °C using trimethylaluminum (TMA) and H2O.