钾钠含量对堇青石蜂窝陶瓷性能的影响

以高岭土、滑石和氧化铝为主要原料采用生料一次烧结工艺制备低膨胀堇青石蜂窝陶瓷,研究了碱金属氧化物K2O和Na2O(用R2O表示)含量对试样热膨胀系数、显气孔率和抗压强度的影响,并利用X射线衍射仪、扫描电镜分析了试样的物相组成和断面形貌.研究表明,R2O含量在0.22;以下时制备的堇青石蜂窝陶瓷的热膨胀系数可达0.56×10 -6/℃,从0.22;增加到0.52;时,热膨胀系数增加到1.58×10-6/℃,显气孔率逐渐降低,而抗压强度增大；R2O含量为0.12;的基础配方试样主要由定向排列的片状堇青石晶粒构成,呈疏松多孔结构,气孔小,随着R2O含量的增加,气孔尺寸变大而数量减少.

Effects of Potassium and Sodium Content on Properties of Cordierite Honeycomb Ceramic

Low thermal expansion cordierite honeycomb ceramics were prepared by one step sintering technique,using kaolin,talcum and α-Al2O3 micro-powders as main starting materials.Effects of alkali oxides K2O and Na2O(R2O) on the coefficient of thermal expansion(CTE),apparent porosity and compressive strength of the prepared cordierite honeycombs were studied.The phase composition and morphology of cross section of the cordierite honeycomb were analyzed by X-ray diffraction(XRD) and scanning electron microscope(SEM),respectively.The results show that the CTE of the cordierite honeycomb is 0.56×10-6/℃ with the content of R2O below 0.22%.The CTE increases to 1.58×10-6/℃ when the R2O content increased from 0.22% to 0.52%.As the R2O content increasing,the apparent porosity decreased gradually and the compressive strength increased.The prepared samples with 0.12% R2O shows a porous microstructure composed of orientation-arranged cordierite crystals and small pores.The pore size becomes bigger and the quantity reduces with the increase of R2O content.