湿化学法制备先进陶瓷粉体的研究现状

湿化学法可以获得尺寸（从微米到纳米级的尺度）和形状（如粉末、纤维、薄膜或块状）可控的先进陶瓷粉体,并且具有较高的反应活性和纯度,是制备先进陶瓷粉体的重要技术手段。本文阐述了几种典型的湿化学法：共沉淀法、溶胶凝胶法、溶剂热法、喷雾热解法、喷雾干燥法、火焰喷雾热解法等在先进陶瓷粉体制备方面的研究现状,总结归纳了湿化学法中急需解决的问题以及未来发展的一些趋势。     

Moisture-proof and enhanced effect of inorganic coating on porous Si<Subscript>3</Subscript>N<Subscript>4</Subscript> ceramic

Inorganic coating was fabricated on the surface of the porous Si₃N₄ ceramic by polymer derived (PD) and spraying technology, via using vinyl-polysilazane (PSN-1) as a preceramic polymer and Si₃N₄ and lithium aluminosilicate (LAS) powders as fillers. The phase and microstructure of the coatings were analyzed by X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM), respectively. The effect of the coatings on mechanical property and humidity resistance of the porous Si₃N₄ ceramic was investigated. The experimental results showed that we successfully fabricated the uniform and dense coating which preferably combined with the substrate upon the addition of fillers. The bending strength of the porous Si₃N₄ ceramic sprayed the coating increased by more than 18%, and the surface hardness increased by 1.7 times. The apparent porosity of the materials reduced by an average of 97.7%, and water absorption was below 0.5%. Therefore, the prepared coating with preferable density had an obviously moisture-proof and enhanced effect on the porous Si₃N₄ ceramic.     

陶瓷天线罩无机涂层的研究进展

通过在天线罩表面制备涂层,可以有效提高天线罩的多方面性能,因此天线罩涂层的研究具有重要的工程价值.本文综述了天线罩无机涂层的制备工艺以及研究进展,指出天线罩涂层研究正朝着提高天线罩基体材料的防潮、抗烧蚀、耐冲刷和耐高温性能以及拓展频带等集多功能于一体的方向发展.