An amorphous ceramic Al32.4Er7.6O60 fiber with large viscous flow deformation and a high-strength nanocrystallized ceramic fiber

An amorphous ceramic Al_32.4Er_7.6O₆₀ continuous fiber with a diameter of about 20 m could be made successfully by using the melt extraction method. This fiber shows large viscous flow deformation at the supercooled liquid state (about 1273 K). The fiber's tensile strength is about 900 MPa and this strength is maintained up to around 1100 K. A high-strength continuous ceramic fiber with a uniform Er₃Al₅O₁₂ nanocrystalline phase in an amorphous matrix can also be obtained with suitable crystallization from the amorphous state by heat treatment. The heat resistance, Young's modulus, and other properties are therefore improved. The nanocrystallized fiber which was heat-treated at 1373 K for 2 hours in an air atmosphere has a maximum room temperature tensile strength of 1.9 GPa, around twice that of an as-extracted amorphous fiber. The amorphous continuous ceramic fiber is promising as a ceramic that can be easily shaped at relatively low temperatures (about 1273 K), and as a reinforcing fiber for composites that can undergo secondary processing. Furthermore, this fiber can be considered as more superior to glass fibers because of its greater high-temperature strength and its high Young's modulus.