【作者】 王铁军；

【导师】 沈毅；

【作者基本信息】 河北理工学院 ， 材料学， 2003， 硕士

【摘要】 我国有丰富的耐火原料资源,其中蓝晶石是一种正被开发利用的重要资源。本文主要研究用蓝晶石为原料制作莫来石-堇青石耐高温材料,并初步探讨了莫来石-堇青石材质的组成、结构与性能之间的关系,目的在于研制一种高性能的耐火窑具（如钵体）材料,以应用于实际陶瓷工业生产中。本论文中以50wt%蓝晶石生料用量,5wt%左右的紫木节作为结合粘土,制配出莫来石-堇青石分别为7:3及3:7的基质,然后复合50wt%的山东焦宝石作为骨料,进行了一系列多个配方、多个烧成温度的试验。通过本项目的研究可知:利用天然原料蓝晶石可以合成性能优良的莫来石-堇青石复相耐火材料。其中MgO（以烧滑石,镁砂形式引入）引入,改善了试样的烧成性能,在烧成温度为1300℃和1350℃液相烧结时,产生的烧结收缩大于蓝晶石莫来石化而产生的体积膨胀效应。通过对烧结后材料的显微结构分析,配方1、2、3、5抗折强度较高的原因是由于这几种配方的材料显微结构较致密,颗粒分布均匀,柱状莫来石均匀分布并且呈网状结构,这就使材料的断裂包含穿晶和沿晶两种形式,因此材料的抗折强度较高;对配方2、6、8来说,从显微结构上看,材料的断裂为穿晶断裂,断裂面不光滑,呈贝壳状,这说明材料中晶界发育比较好,具有较高的强度。当有外力作用时,裂纹的扩展不在晶界中进行,而是穿过晶粒内部造成断裂,这样材料就具有较高的强度。本实验的结果表明:粉料的颗粒级配对天然原料蓝晶石生产有很重要的影响。本实验中,由于颗粒级配和原料产地不同,所得的实验结果出现较大差异。另外,在本论文中,进一步分析了原料添加剂和温度对材料性能的影响。对添加剂作用的初步研究证明:适量的添加剂（CaO、TiO₂、Fe₂O₃、R₂O）能与原料的主晶相形成固溶体,使主晶相中缺陷浓度增大,粒子扩散速度加快,促进了固相发应和烧结的进行。对堇青石的形成有利。但原料添加剂存在一个最佳的范围,添加剂含量过高,会导致玻璃相含量的增加,导致热稳定性的降低。最佳的控制范围为CaO<2.0wt%、TiO₂<2.0wt%,最好不要存在Fe₂O₃,尽量控制R₂O量。更多还原

【Abstract】 China is abundant of refractory resources, in which kyanite is one of importance and being developed recently. In the work, the application of kyanite in the preparation of mullite-cordierite refractory, the effect of composition and microstructure of the aforesaid material versus its properties are discussed. The goal in the present work is to develop high performance kiln furniture, which is saggar in particular, to match with the need in ceramics fabrication.50wt% raw kyanite was applied in the composition,±5wt% Zhimujie （a kind of secondary clay of high plasticity） as binder was added to compose matrices of 7:3 and 3:7 mullite/cordierite ratios. Besides a 50wt% of Jiaobaoshi （a kind of Shandong boxite） was added as aggregate. Experiments on different batch compositions and firing temperetures have been carried out. From the work it has shown that a synthesized mullite-cordierite of good performance can be obtained by using raw kyanite. MgO can be introduced by means of adding calcined talc or magnesia. Under the firing temperatures of 1300 and 1350 oC, by liquid phase sintering, the firing shrinkage will overcome the expansion process due to the formation of mullite. Through the tests of the as fired samples, batches of 1#, 2#, 3# and 4# have shown a high bending strength, it is due to fairly dense microstructure and even grains distribution, the needle like mullite garains has formed a skeletal structure. Owing to such a structure, crack will propagate along grain boundaries and transboundaries inside the material. Microstructures of samples 2#, 6#, 8# have shown the appearance of transgrain fracture, which have given rise to a conchoidal fracture surface. It has implied to a product of well-developed grain boundaries, and has given the samples of high bending strength. From the tests they have shown also that the particle size distribution and the nature of kyanite will affect the end result. By applying different particle size and different origin of kyanite there was quite a tremendous deviation of the result. The work has also carried out experiments on the role of additives and the effect of firing temperatures. An adequate additives （CaO, TiO₂, Fe₂O₃, R₂O） will help the formation of liquid phase, and enhanced the sintering process, however, the additives added should be in an adequate quantity, excessive additive will give rise to the increase of glass phase and will decrease the temperature shock resistivity. The optimum range of the additive is, CaO<2.0 wt%, TiO₂<2.0 wt%, it is necessary to avoid the existent of Fe₂O₃ and limits strictly the amount of R₂O.更多还原