Interfacially-engineered trifunctional high-temperature nano/microstructured aluminum nitride ceramic for evaporation-based technologies

Abstract

For the first time, a trifunctional high-temperature AlN ceramic material that combines the extreme wicking, evaporative, and cooling functionalities for enhancing the efficiency of evaporation-based technologies was created through engineering a hierarchical surface nano/microstructure. The developed interfacially-engineered structure is an array of tapered micropillars, the surface of which is textured with irregular/regular nanostructures. The created material exhibits excellent wicking, evaporative, and cooling functionalities in a temperature range of 23–230 °C, both in the absence and presence of airflow. The wicking functionality provides unprecedentedly fast capillary flow of intensively boiling water on the AlN surface, even at a temperature of 230 °C. The developed ceramic also provides a very efficient evaporative cooling performance (from 230 to 126 °C). Our important result is a high evaporation rate of the AlN material at various airflows that exceeds that of a free water surface by a factor of 2.5–7.5, depending on the airflow velocity and temperature. The excellent performance of the trifunctional AlN ceramic at low and high temperatures under various airflow conditions shows its great potential for a large variety of evaporation-based technologies, including dew-point (DP) evaporative cooling systems for increasing power generation efficiency, water purification/desalination, thermal management, waste heat recovery, and other existing and emerging evaporation-based technologies.

Keywords

• Aluminum nitride
• Interface nano/microstructures
• Wicking
• Laser processing
• Evaporation