| In this paper, ceramic wave transparent materials in the application of space aircraftradome based on design, material, according to the zirconium oxide whisker magnesium boratewhisker and aluminum phosphate excellent mechanical properties and dielectric propertieswere prepared by the whisker, meet the performance requirements of the composite materialreinforced aluminum phosphate based ceramics, and the volume density, apparent porosity,bending strength, hardness, Vivtorinox thermal shock resistance, dielectric properties weretested and analyzed, discussed the zirconium oxide whisker reinforcing and tougheningmechanisms of aluminum phosphate matrix composite materials, improve and enrich thealuminum phosphate based transparent material systems, which has important theoretical andpractical significance to scientific wave material.Phosphate wave transparent materials with high strength, high temperature resistance,oxidation resistance, excellent dielectric property, low coefficient of thermal expansion andstructural features of good design, can meet a variety of military, civilian special request, is theideal material for high temperature resistance, low dielectric loss, and widely used in a varietyof aircraft, missiles, the rockets and the space shuttle. Reinforced aluminum phosphate matrixcan overcome the mechanical performance of aluminum phosphate is not high. With thewhisker reinforced ceramic wave transparent material, base with two or more than two kinds ofwhiskers, namely the hybrid whisker reinforced can overcome the disadvantages of singlewhisker reinforced materials, will get even better comprehensive performance. The elasticmodulus and tensile strength of zirconia whiskers high, performance remained stable at hightemperature, and has good physical and chemical compatibility with aluminum phosphate, verysuitable for reinforcement as ceramic wave transparent materials. The magnesium boratewhisker high elastic modulus, good mechanical strength, has the chemical resistance, heatresistance, acid resistance, neutron absorption and excellent performance of electricalinsulation, and low dielectric constant, can be chosen as the reinforced body wave transparentmaterials. So, choose to use zirconia whiskers and magnesium borate whisker reinforcedaluminum phosphate matrix material, in order to improve the mechanical properties ofaluminum phosphate, can further expand the aluminum phosphate wave transparent materials are used in the aerospace.By normal pressure sintering technology, select the appropriate whisker ratio and sinteringsystem reasonable, prepared zirconium oxide whisker reinforced aluminum phosphate matrixceramic wave transparent material and zirconium oxide whisker magnesium borate whiskerreinforced aluminum phosphate based common ceramic wave transparent material, and thebulk density, apparent porosity, bending strength and hardness, Vivtorinox, thermal shockresistance, dielectric properties were tested and analyzed, discussed the zirconium oxidewhisker reinforcing and toughening mechanisms of aluminum phosphate matrix material.The effects of different zirconium oxide whisker content, different sintering temperatureon bulk density, apparent porosity of ceramic composites, flexural strength, Vivtorinoxhardness, thermal shock resistance and dielectric properties. The experimental results show that:the same sintering temperature, the higher the whisker content of zirconia, volume densitywave transparent materials, the more significant the smaller porosity; under the same zirconiumoxide whisker content, along with the sintering temperature was increased, the bulk densityincrease and slightly downward trend, apparent porosity decreased slightly after increased;when the zirconium oxide whisker content at the same time, along with the sinteringtemperature increasing, the aluminum phosphate matrix radome material bending strength andhardness are Vivtorinox first increased and then decreased; adding zirconia whiskers can makethe aluminum phosphate matrix radome material thermal shock resistance, dielectricperformance enhancement. When the whisker content of zirconium oxide is20%, the sinteringtemperature is620℃, the comprehensive properties of aluminum phosphate medium wavetransmitting materials, various technical indicators are: the bending strength of Vivtorinox210MPa, hardness180MPa, dielectric constant is2.87, the dielectric loss angle tangent value of0.02425.Influence of sintering temperature on the different content and ratio of zirconia whiskersand magnesium borate whisker, different on bulk density, apparent porosity of ceramiccomposites, flexural strength, Vivtorinox hardness, thermal shock resistance and dielectricproperties. The experimental results show that: when the zirconia whiskers and magnesiumborate whisker content ratio of1:1, zirconium oxide whiskers and magnesium borate whiskercontent was30%, and the sintering temperature is800℃, the most excellent comprehensive properties of zirconium oxide whisker magnesium borate whisker reinforced aluminumphosphate medium wave transmitting materials, various technical indicators respectively.: therelative density of1.83g/cm3, apparent porosity of0.18, the flexural strength of Vivtorinox90MPa, hardness216MPa, dielectric constant is2.62, the dielectric loss angle tangent value of0.06350; compared with zirconium oxide whiskers and magnesium borate whisker content andthe sintering temperature, the maximum effect of comprehensive performance test materialcontent; adding zirconia whiskers can make the hardness of the material and thermal shockresistance improved significantly.According to the theory of toughening the whisker reinforced, the mechanism of thezirconium oxide whisker wave transmitting materials reinforced aluminum phosphate basedceramics, the author analysis: the introduction of zirconium oxide whiskers can improve thealuminum phosphate matrix strength and toughness, deflection, crack bridging and whisker,whisker pullout is the main reason for the ceramic wave transparent material strength andtoughness. |
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