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 CN bond on 287.5 eV, which revealed that AlN and carbon foam through CN 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.