The researchers found that in contact between a solid and a liquid there is order within the liquid
Researchers from the Faculty of Materials Engineering and the Berry Institute for Research in Nanotechnology at the Technion in collaboration with researchers from the "Max Planck" Institute in Stuttgart, Germany, have proven the existence of a new state in nature. This is what the prestigious scientific newspaper "Science" reveals. Doctoral student Yaron Kaufman, under the guidance of Professor Wayne Kaplan, found that in contact between a solid and a liquid, there is an intermediate layer where order exists within the liquid. In doing so, they proved a hypothesis that had existed for decades, but so far had not been directly proven.
The researchers found that when close to the crystal (sapphire stone), the liquid (in this case liquid aluminum) no longer behaves like a liquid and the proximity to the crystal causes the atoms in the liquid to line up. "A crystal is defined as a substance in which the atoms are arranged in space in a cyclical and long-term manner, and the liquid - as a substance in which the atoms are not arranged in the long-term," explain the Technion researchers. "The meaning of the discovery is that at the meeting between a crystal and a liquid there exists an intermediate state, which is neither a solid crystal nor a liquid."
During the research, the researchers used a powerful electron microscope at the Max Planck Institute in Stuttgart, which allowed them to heat the sapphire stone up to a temperature of 750 degrees Celsius and at the same time examine under the microscope lenses the intermediate surface between the liquid aluminum and the sapphire at the atomic level.
Sapphire can also be produced artificially, as is currently done in industry. It is a transparent material like glass, strong, hard and scratch-resistant dozens of times more than glass. The research also revealed for the first time the growth mechanism of the sapphire crystal, which was not known until now.
Technion researchers are now focusing on controlling the crystalline structure that the liquid takes on during solidification. They believe that this is possible as a result of the solidification of the liquid in proximity to surfaces with different geometrical constraints. Thanks to this control, they will be able to obtain structures that do not currently exist in nature, thus obtaining various engineering properties with the help of which it will be possible to create new materials for microelectronics and even optical devices.
Understanding the nature of intermediate surfaces between liquid and solid is of great importance in various technological processes, such as solidification, wetting, connection processes in the liquid phase, crystal growth and lubrication processes. This work proves that the high resolution penetrating electron microscope is one of the most powerful methods for investigating materials on the nanometer scale. In the near future, a unique electron microscope of its kind in the world will arrive at the Technion, as part of the Berry Institute for Research in Nanotechnology, which will make it possible to conduct similar and even more advanced research in Israel.
