Multilayer ceramic composites with high failure resistance

Since Clegg et al. first fabricated SiC/C multilayer composites in 1990, multilayer ceramics have received much attention because of their improved properties achieved by designing weak interfaces. The weak interface can deflect the crack propagating perpendicularly to the plane of laminates repeatedly during fracture, thus leading to extremely high work-of-fracture. In this work multilayer composites of Al2O3/LaPO4 were prepared using tape casting technique. Alumina slurry with acrylic latex binder was cast first on a polyester film, dried and then coated by LaPO4 interlayer cast on it. The coated green tapes were dried, stacked and laminated. After the removal of the binder, the green body was hot pressed in argon atmosphere at 1280 °C. A series of experiments were designed and conducted to investigate the influence of geometrical factors on mechanical properties of multilayer composites. Work-of-fracture of layered composites as high as 1100 J/m2 has been found.