粒度对低温燃烧合成堇青石粉相变和烧结性能的影响.doc

摘  要:以硝酸镁、硝酸铝、硅酸为原料，尿素为燃料，用低温燃烧法简便快捷地合成堇青石前驱粉。在堇青石前驱粉中加入适量的粘结剂于170MPa下干压成片,在不同温度下烧结，获得堇青石基玻璃陶瓷。

　　　根据阿基米德原理，用排水法测量烧结体的密度，研究不同粒度的粉体对低温燃烧合成堇青石粉烧结性能的影响；通过x-射线衍射分析样品的物相，研究不同粒度的粉体对堇青石析晶性能的影响。结果表明：

　　　（1）以Mg(NO3)2·6H2O, Al(NO3)3·9H2O和H2SiO3为原料， CO(NH2)2为燃料可用低温燃烧法制备堇青石基玻璃陶瓷。

　　　（2）低温燃烧法制备堇青石基玻璃陶瓷的析晶过程为：非晶态 → μ-堇青石 → α-堇青石。

　　　（3）用低温燃烧法制备堇青石基玻璃陶瓷时，在同温同压的同等条件下，用粒度小的前驱粉比用粒度大的前驱粉更有利于α-堇青石晶相的获得。

　　　（4）同温下烧结体的线收缩率随粒度的增大而减小。

　　　（5）不同种晶体密度不同，混晶物密度与各晶相含量相关。

关键词：粒度；低温燃烧；堇青石；析晶；烧结

ABSTRACT:The MgO-Al2O3-SiO2(MAS) glass powders have been synthesized by low-temperature combustion technique using magnesium nitrate, aluminium nitrate, silicic acid as material, urea as fuel. The crystallization process and sintering behavior were investigated. We can obtain cordierite based glass ceramics in the cordierite precursor powder with an appropriate amount of binder in the dry-pressed under 170MPa into a film, sintered at different temperatures.

　　　According to Archimedes, with a water density measurement of sintering, powders with different particle size of low-temperature combustion synthesis of cordierite powder sintering; Analyzing the effects of different size The powder on the properties of cordierite crystallization through the samples of X-ray diffraction phase . The results shows:

　　　(1) We can use the Mg (NO3) 2 • 6H2O, Al (NO3) 3 • 9H2O and H2SiO3 as raw materials, CO (NH2) 2 as the fuel temperature to combust Cordierite precursor powder.

　　　(2) The precipitation process of making cordierite-based glass ceramics under the low-temperature combustion is: chromatography amorphous → α-cordierite →μcordierite. 

　　　(3) When prepared the cordierite-based glass ceramics with low-temperature combustion, the small size particle precursor powder is better than the large size precursor powder to get the alpha cordierite under same temperature and pressure condition. 

　　　(4) Under the same temperature, line shrinkage rate of sintered body decreased with the increase of granularity. 

　　 (5) Different kinds of crystals have different density; the density of mixed grain material is interrelated to the crystalline phase content.

Key words: powder; low-temperature combustion synthesis; cordierite; crystallization; sintering;