退火重结晶制备AlN/C复合泡沫材料及其力学性能研究

为了得到一种轻质、高强度、耐烧灼的新型碳泡沫材料,以无定形AlN为添加剂,在空心微球/网络复合型碳泡沫的基础上,采用退火热处理工艺成功地制备出了AlN/C复合泡沫材料.通过扫描电镜、透射电镜对样品进行表征,测试结果表明无定形AlN在碳微球的表面重结晶为AlN晶须,其直径大约为50nm左右,长度10μm以上,具有较大的长径比.X-射线衍射峰证明样品石墨化程度高,且AlN晶须为六方结构.X-射线光电子能谱测试发现在287.5eV处有较明显的C-N峰出现,这表明AlN和碳泡沫在界面处通过C-N键结合.同时,对其力学性能进行测试,通过分析应力-应变测试结果,AlN/C复合泡沫材料的压缩强度为40.27MPa,相对碳泡沫材料而言提高了近一个数量级.测试结果表明,AlN晶须显著增强了碳泡沫的压缩强度,这种新型复合泡沫材料有望应用于各种抗压减震航空材料.

Preparation of AlN/C composite foam through annealing recrystallization and its mechanical performance study

Order to get a new type carbon foam material, AlN/C composite foam was successfully synthesized by using AlN as an additive and hollow microspheres/reticulated carbon foam as a basement thought the annealing high-temperature heated process. The prepared samples were characterized by Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM). The results of test indicated that AlN whiskers with diameter of 50nm, length large than 10 um and larger length-diameter ratio were prepared by amorphous AlN recrystallization at the surface of carbon microspheres. Diffraction peaks of XRD demonstrated that the sample was characterized as graphitization and AlN whiskers were hexagonal structure. XPS test showed that there was an obvious peak of C-N bond on 287.5 eV, which revealed that AlN and carbon foam through C-N bond combined on their interfaces. Meanwhile, it was showed that AlN/C foam material's compression strength was 40.27 MPa through the analysis of the stress-strain of mechanical performance, which increased nearly one order of magnitude compared with the carbon foam material. The results of test showed that compressive strength of carbon foam was obvious reinforced by AlN whisker. And this new composite foam has infinite applications value in various kinds of resist compression and absorbing aeronautical materials.