Ordered liquid aluminum at the interface with sapphire

Area of Science:

• Materials Science
• Surface Science
• Nanotechnology

Background:

• Solid-liquid interfaces are crucial for numerous technological applications, including crystal growth and lubrication.
• Previous research suggested density fluctuations at these interfaces through indirect methods like X-ray scattering and simulations.

Purpose of the Study:

• To provide direct, atomic-scale evidence of liquid atom ordering adjacent to a crystal interface.
• To investigate the in situ crystal growth of alumina into liquid aluminum.

Main Methods:

• Real-time, high-temperature observations of alumina-aluminum solid-liquid interfaces using atomic-length scale microscopy.
• High-resolution transmission electron microscopy (HRTEM) for in situ observation of crystal growth.

Main Results:

• Direct evidence of ordered liquid aluminum atoms adjacent to the alumina crystal interface was observed.
• In situ observation of alumina crystal growth into liquid aluminum was achieved.
• Interfacial transport of oxygen from the microscope column facilitated the observed crystal growth.

Conclusions:

• Atomic-level ordering exists at solid-liquid interfaces, challenging previous indirect observations.
• The findings offer new insights into interfacial phenomena relevant to materials processing and crystal growth.
• In situ HRTEM is a powerful tool for studying dynamic processes at solid-liquid interfaces.