Resilient Si_(3)N_(4)@SiO_(2)nanowire aerogels for high-temperature electromagnetic wave transparency and thermal insulation

作     者：Wei Zhang Lei Su De Lu Kang Peng Min Niu Lei Zhuang Jian Feng Hongjie Wang 

作者机构：State Key Laboratory for Mechanical Behavior of MaterialsXi’an Jiaotong UniversityXi’an 710049China Science and Technology on Advanced Ceramic Fibers and Composites LaboratoryNational University of Defense TechnologyChangsha 410073China 

出 版 物：《Journal of Advanced Ceramics》 (先进陶瓷（英文）)

年 卷 期：2023年第12卷第11期

页      面：2112-2122页

核心收录：

学科分类：08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）] 0703[理学-化学] 

基　　金：support from the National Natural Science Foundation of China(Nos.92263204 52072294 and 52102076). 

主　　题：electromagnetic wave transparency resilient ceramic aerogels high-temperature stability fire resistance high-temperature resistance 

摘      要：With the development of aerospace technology,the Mach number of aircraft continues to increase,which puts forward higher performance requirements for high-temperature wave-transparent materials.Silicon nitrides have excellent mechanical properties,high-temperature stability,and oxidation resistance,but their brittleness and high dielectric constant impede their practical applications.Herein,by employing a template-assisted precursor pyrolysis method,we prepared a class of Si_(3)N_(4)@SiO_(2)nanowire aerogels(Si_(3)N_(4)@SiO_(2)NWAGs)that are assembled by Si_(3)N_(4)@SiO_(2)nanowires with diameters ranging from 386 to 631 nm.Si_(3)N_(4)@SiO_(2)NWAGs have low density of 12–31 mg∙cm^(−3),specific surface area of 4.13 m^(2)∙g^(−1),and average pore size of 68.9μm.Mechanical properties characterization shows that the aerogels exhibit reversible compressibility from 60%compressive strain and good fatigue resistance even when being compressed 100 times at set strain of 20%.The aerogels also show good thermal insulation performance(0.032 W·m^(−1)∙K^(−1) at room temperature),ablation resistance(butane blow torch),and high-temperature stability(maximum service temperature in air over 1200℃).The dielectric constant and loss of the aerogels are 1.02–1.06 and 4.3×10^(−5)–1.4×10^(−3) at room temperature,respectively.The combination of good mechanical,thermal,and dielectric properties makes Si_(3)N_(4)@SiO_(2)NWAGs promising ultralight wave-transparent and thermally insulating materials for applications at high temperatures.