无机复合材料.pptVIP

Fabrication and characterization of three dimensional woven carbon fiber /silica ceramic matrix composites Reporter:Zhang bao jie Gao T, Zhao Y, Zhou G, et al. Composites Part B: Engineering, 2015, 77: 122-128. Introduction Fiber reinforced ceramic matrix composites (CMCs) possess advantages of lower density, better toughness and higher specific strength than monolithic ceramic materials.Therefore, fiber reinforced CMCs have an increasingly important application. low impact resistance and complicated manufacture processes and delamination and anisotropy of mechanical properties are the disadvantages of unidirectional and 2D structure reinforced CMCs. The main processing routes for 3D structure reinforced CMCs are chemical vapor infiltration (CVI) and precursor infiltration and pyrolysis (PIP).but they all have disadvantages.such as high energy consumption , high cost and often exhibit substantial porosity. In order to develop more efficient processing method for CMCs,a novel modified slurry impregnation and hot pressing (SIHP)method is developed in current study to make three dimensional woven preform reinforced carbon fiber/silica CMCs (3D Cf/SiO2 CMC). Unlike the traditional SIHP process based on continuous fiber impregnation and filament winding, silica slurry was first injected and coated around fibers and in between fiber layers during weaving process, then vacuum assistant slurry transfer molding (VASTM) method was applied to assist slurry infiltration into the voids in the perform to densify the composite and lower the porosity. Experimental 1.Materials polyacrylonitrile (PAN); The matrix silica powder (SiO2: 99.28 wt.% pure, and average particle size around 4.8 mm) and dispersing agent (isopropyl alcohol)were mixed by ball-milling machine for 4 h, using distilled water as the solvent to form homogenous silica slurry. 2.Fabrication and sintering The 3D orthogonal preformwas composed of 3 warp and 4 weft layers as shown in Fig. 1. The