Development and application of a high-temperature imaging system for in-situ scanning electron microscope

In-situ scanning electron microscope (SEM) is essential for investigating materials' properties. In this study, a custom-built in-situ heating system was developed to improve SEM imaging at elevated temperatures. A heater equipped with a double helical tungsten filament was specifically designed to achieve unprecedented high temperatures for heating materials. A bias-voltage control system was proposed to suppress thermal electrons during heating. Additionally, a high-temperature secondary-electron detector was developed and equipped with a variable visible-light filter to mitigate the impact of visible and infrared light at high temperatures. The heater and detector worked within a high vacuum environment with a pressure level below 1 x 10-3 Pa. Two in-situ heating experiments were conducted using the heating system to observe the melting and crystallizing pro-cesses of cobalt and the phase transformation of carbon steel. The results exhibited the remarkable capability of the heating system to image at temperatures as high as 1500 degrees C, offering a resolution of 40 nm. This heater is anticipated to advance materials characterization, providing comprehensive insights into their behavior at high temperatures and opening new avenues for developing material properties.