Research on Preparation and Performance of Al2O3 Fiber Reinforced Ceramic Wave-Transparent Composite Containing LaPO4 Interface
Alumina fiber reinforced ceramic matrix composites are characterized by good mechanical properties,high temperature oxidation resistance,corrosion resistance and excellent dielectric properties.This material can be used as a kind of high temperature-resistant wave-transmitting functional material for radome.Taking Al2O3 and mullite slurry as basement,Al2O3 fiber as reinforcement,and LaPO4 as interface,Al2O3/Al2O3 composite is fab-ricated by repeating infiltration and high temperature treatment process.And then,the tensile strength of the composites at room temperature and 1 200℃are measured,and the SEM is employed in observing the fracture microstructure.The tensile strength of Al2O3/Al2O3 composites with LaPO4 interface at room temperature is 148.3 MPa,and increment of tensile strength is 20.1%in comparison with Al2O3/Al2O3 composites without in-terface.The tensile strength of Al2O3/Al2O3 composites with LaPO4 interface at 1 200℃is 129.6 MPa,and its increment is 24.9%in comparison with Al2O3/Al2O3 composites without LaPO4 interface.The SEM observation shows that the fracture surface of the composite without LaPO4 interface is smooth at crack,and brittle in frac-ture.A large number of fibers are pulled out in the fracture of alumina fiber reinforced ceramic matrix composites with LaPO4 interface phase,showing ductile fracture characteristics.The average dielectric constant of the com-posite material is 5.77 and the dielectric loss is 0.001 8 when the frequency is 10 GHz and RT;the average dielec-tric constant of the material at 1 300℃is 6.18 with the dielectric loss is 0.002 0.The change rate of electric con-stant and dielectric loss is 7.10%and 11.1%respectively,meeting the needs of change rate<15%,and such a material is expected to be used in the field of wave-transparent composite materials.
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