Fabrication of high density cordierite ceramics using a coal fly ash
Fabrication of high density cordierite ceramics using a coal fly ash
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DOI：
10.2109/jcersj2.118.231
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发表时间：
2010
影响因子：
1.1
通讯作者：
T. Ogiwara;Yoshimasa Noda;O. Kimura
中科院分区：
文献类型：
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作者：
T. Ogiwara;Yoshimasa Noda;O. Kimura
以粉煤灰为原料制备高致密堇青石陶瓷。然而，在以前的研究中，由于利用粉煤灰没有细粉化，只能得到多孔堇青石陶瓷。这是因为粉煤灰一般都很难被精细粉碎。此外，没有关于所获得的堇青石陶瓷的性能的详细信息。通过对粉煤灰粉碎工艺的改进，成功地实现了粉煤灰的粉碎。也就是说，其原始晶粒尺寸12 μm可以减小到1.2 μm。将粉碎的粉煤灰与氧化镁和氧化铝源在湿式球磨机中混合。X射线衍射显示，仅在1150°C下热处理的样品中存在堇青石相。烧结粉末的密度达到理论密度的97%，这超过了HIP处理所需的值= 95%。与使用未粉碎粉末的烧结样品相比，使用粉碎粉末的烧结样品显示出足够高的热机械性能和电性能。用该粉末制备的试样的抗弯强度为132 MPa，断裂韧性为3.0 MPa·m1/2，热膨胀系数为2.1 × 10-6/K，介电常数为6.5。热等静压处理提高了试样的弯曲强度，抑制了气泡的形成。
The aim of this study is to obtain highly densified cordierite ceramics using a coal fly ash as one of the starting raw materials. In the previous studies, however, only porous cordierite ceramics were obtained since the utilized coal fly ashes were not finely pulverized. It was because fly ash was generally so hard to be finely pulverized. In addition, no detailed information for the properties of the obtained cordierite ceramics was available. We succeeded in pulverizing the fly ash by improving pulverizing procedure. Namely, its original grain size of 12 μm could be decreased to 1.2 μm. The pulverized fly ash was mixed with magnesia and alumina sources in a wet ball mill. X-ray diffraction revealed the presence of cordierite phase only for the sample heat-treated at 1150°C. The density of the sintered powder reached 97% theoretical, which was beyond the value required for HIP treatment = 95%. The sintered samples using the pulverized powder revealed sufficiently high thermo-mechanical and electrical properties compared with those of the sintered samples using the unpulverized powder. For instance, flexural strength of 132 MPa, fracture toughness of 3.0 MPa·m1/2 , thermal expansion coefficient of 2.1 × 10-6/K and dielectric constant of 6.5 were obtained for the sample using the pulverized powder. HIP treatment enhanced flexural strength of the treated samples and suppressed bubble formation in them.