A team of researchers from MIT recently demonstrated a new electrochemical method to study thermodynamic processes in an ultra-high temperature molten oxide. In an effort to find new insights into the thermodynamic properties of refractory materials, researchers have developed a container-less electrochemical method to study thermodynamic properties of materials like aluminum oxide, which melts at temperatures above 2,000 degrees Celsius.
The finding were reported in the open access paper, “Electrochemical Study of a Pendant Molten Alumina Droplet and Its Application for Thermodynamic Property Measurements of Al-Ir,” which was recently published in the Journal of The Electrochemical Society.
“We have a new technique which demonstrates that the rules of electrochemistry are followed for these refractory melts,” says senior author Antoine Allanore, an associate professor of metallurgy and member of ECS. “We have now evidence that these melts are very stable at high temperature, they have high conductivity.”
This from MIT:
Adapting a thermal imaging (or arc imaging) furnace more commonly used for floating zone crystal growth, MIT graduate student Brad Nakanishi melted an alumina (aluminum oxide) rod and contacted the liquid pendant droplet that it formed with electrodes, creating an electrochemical cell that allowed decomposition of pure, alumina electrolyte to oxygen gas and aluminum alloy by electrolysis for the first time. The aluminum oxide itself serves as the electrolyte in this electrochemical cell, which operates similarly to water electrolysis.
“Decomposition voltage measurements give us direct access to the quintessential thermodynamic property that is chemical potential, also called Gibbs energy,” Nakanishi says. “We’ve shown we make electrochemical measurements in a new class of electrolytes, the molten refractory oxides.”
Using this technique, four reflected xenon lamps hone in on the tip of the sample, melting a liquid droplet, which is held to the rod by surface tension and quickly solidifies after the lights are turned off. While the droplet is liquefied, the electrodes are raised into the droplet to complete an electrical circuit, with the liquid alumina itself functioning as the electrolyte.
The researchers believe this new development could help predict industrial questions, such as how hot a turbine engine can run.
