Japanese researchers have developed a new type of glass almost as hard as steel, a breakthrough that could lead to the development of substantially tougher windows and tableware.
Thinner and lighter and stronger glass are desired for windows in buildings and cars, substrates for TFT displays, and smart-phones.
“We will establish a way to mass-produce the new material shortly,” said Atsunobu Masuno, an assistant professor at the University of Tokyo’s Institute of Industrial Science. “We are looking to commercialize the technique within five years.”
Oxide glass mainly consists of silicon dioxide, with its strength boosted by mixing in alumina, an oxide of aluminum. But it had been difficult for scientists to form glass containing a large amount of alumina because the oxide causes crystallization when the glass comes into contact with its container.
The scientists bypassed this problem by using a containerless processing technique.
The plan is to commercialize the steel hard glass within 5 years.
Ingredients pushed into the air with gas synthesize to form a new type of glass. (Provided by the University of Tokyo’s Institute of Industrial Science)
They used gas to push the chemical components into the air where they synthesized to form the glass. The resultant glass was colorless, transparent and very tough, 50 percent of it being composed of alumina.
The Young’s modulus of the new glass, an indicator of rigidity, was twice as high than typical oxide glass and almost at the same level as steel and iron, according to the scientists.
Glasses with high elastic moduli have been in demand for many years because the thickness of such glasses can be reduced while maintaining its strength. Moreover, thinner and lighter glasses are desired for the fabrication of windows in buildings and cars, cover glasses for smart-phones and substrates in Thin-Film Transistor (TFT) displays. In this work, we report a 54Al2O3-46Ta2O5 glass fabricated by aerodynamic levitation which possesses one of the highest elastic moduli and hardness for oxide glasses also displaying excellent optical properties. The glass was colorless and transparent in the visible region, and its refractive index nd was as high as 1.94. The measured Young’s modulus and Vickers hardness were 158.3 GPa and 9.1 GPa, respectively, which are comparable to the previously reported highest values for oxide glasses. Analysis made using 27Al Magic Angle Spinning Nuclear Magnetic Resonance (MAS NMR) spectroscopy revealed the presence of a significantly large fraction of high-coordinated Al in addition to four-coordinated Al in the glass. The high elastic modulus and hardness are attributed to both the large cationic field strength of Ta5+ ions and the large dissociation energies per unit volume of Al2O3 and Ta2O5.