Improved heating method for shape-memory alloy using carbon nanotube and silver paste

Abstract

Shape memory alloys (SMAs) have a special ability to remember their initial shape and return from operating temperature. For this special ability, there are many studies in the field of smart wearables to replace rigid, heavy, and large electric actuators with SMAs that can be a fabrication. The usual operating method of the SMA is heating the SMA by direct Joule heating with electricity. Although direct Joule heating is fast and easy, there is overshooting, unstable, and high-power consumption. For these issues to use the SMA as textile actuators, this research suggested a heating method with silver paste required lower power consumption and coating the basic fabric with carbon nanotubes (CNTs) to support heating stability and heat uniformity. The heating method evaluated the efficiency of heat by comparing direct heating and silver layer heating and the uniformity of heat with the infrared images of whether CNTs coated or not. In this research, we reached higher temperatures with lower power than direct Joule heating using wearable heaters manufactured using silver paste. In addition, we confirmed that coating the basic fabric with carbon nanotubes reduce the temperature imbalance, and improved the heating stability. This research is expected that SMA will be used as a wearable actuator to help develop wearable devices that can move.