ساختار چند لایه ساندویچی جدید برای اختفای مادون قرمز
Abstract
1- Introduction
2- Experimental section
3- Results and discussion
4- Conclusions
References
Abstract
At present, infrared stealth materials for advanced detection and stealth technology is usually prepared with low emissivity coating on the surface, but there are very few efficient infrared stealth materials based on textiles with lightweight and flexible features. In this paper, we designed a carbon nanotube-doped aerogel (CNTAs) sandwich structure on polyimide (PI) fabric by hot pressing and then coated with a low emissivity Al-doped ZnO (ZAO) on the outer surface. The surface emissivity lower than 0.5 due to the existence of ZAO and the thermal conductivity of the intermediate interlayer aerogels as low as 0.013 W/(m·K). Additionally, through experiments, theoretical derivation and simulation analysis, we found the resultant composite demonstrated a high infrared stealth performance with super insulation effect, implying it will have a fine prospect in infrared stealth and thermal insulation protection fields with its unique structure and excellent properties.
Introduction
With the rapid development of infrared (IR) detection systems and the improvement of detection accuracy, the security and survival of military equipment and facilities have been seriously threatened [1-3]. Therefore, IR stealth provides a guarantee for the survival of soldiers and weapons, and plays an extremely important role in the battlefield [4, 5]. However, all objects above absolute zero will emit IR radiation [6], and IR detection just relies on the difference in IR radiation between the target and the background to detect the target [1]. Needless to say, soldiers and weapons often have higher temperatures than their environment, especially at night, as they will exhibit high brightness on an infrared thermal imaging in contrast with the background[6]. According to Stefan-Boltzmann's law[7], there are two main methods to reduce the infrared radiation of the target: one is to reduce the emissivity of the target surface; the other is to control the temperature of the target surface. Therefore, take these two factors into account; the key to stealth technique is to prepare a functional composite with isolate heat structure inside combining with low surface emissivity outside. This functional composite can not only used in infrared stealth fields, but also in high-temperature environments such as steelmaking, ironmaking, and firefighting when based on textiles as it has a good heat isolation function with flexible and lightweight features[8]. This composite can also be used in the energy-saving fields like building upholstery [8, 9]. Therefore, the development of infrared stealth material based on textiles with excellent thermal insulation properties is great significance, while fire retardancy, resilience and flexibility are also demanded in practical use [8, 10].