以石墨为造孔剂制备堇青石多孔陶瓷材料

Prepartion of porous cordierite ceramics using graphite as pore forming agen

以滑石、高岭土、氧化铝、氢氧化铝和二氧化硅为原料,采用基础配方(w):氧化铝17.8%、氢氧化铝4.5%、滑石42.4%、煅烧高岭土22.6%、生高岭土5.7%、二氧化硅7%,分别外加0、25%、35%、45%、55%质量分数的石墨做造孔剂,以PVA为结合剂,经混合、成型后,分别在1 250、1 300、1 350℃保温1 h热处理而制备了适用于汽油机颗粒物捕集器(GPF)的堇青石多孔陶瓷材料,并对该试样进行了XRD和SEM分析、孔径大小和分布、显气孔率以及烧结等性能的研究。结果表明:以石墨为造孔剂,在1 300℃保温1 h可以制备出微孔化且孔径大小呈梯度分布的堇青石多孔材料;改变石墨加入量,可以有效控制试样的气孔率、孔径大小及孔径分布,当石墨质量分数为45%左右时,试样的显气孔率最大,抗折强度也较高,综合性能较好。

The basic formulation was 17.8% （in mass,the same hereinafter）Al2O3,4.5% Al（OH）3,42.4%talc,22.6%calcined kaolin,5.7% raw kaolin,7%SiO2.Based on the basic formulation,the porous cordier-ite ceramics for gasoline particulate filter （GPF）were prepared by extra adding graphite as pore forming agent （0,25%,35%,45 and 55%,respectively）,PVA as binder,mixing,shaping,and firing at 1 250,1 300 and 1 350 ℃ for 1 h,respectively.The specimens were analyzed by XRD and SEM.The pore size distribu-tion,apparent porosity and sintering properties were researched.The results show that the porous cordier-ite ceramic with gradient distributed micropores can be prepared using graphite as pore forming agent af-ter fired at 1 300 ℃for 1 h;the porosity,pore size and its distribution can be controlled by changing graph-ite addition;when graphite addition is 45%,the ceramics perform good properties including the highest ap-parent porosity and good modulus of rupture.