【作者】 周志军；

【导师】 肖汉宁； 李顺禄；

【作者基本信息】 湖南大学 ， 材料工程， 2007， 硕士

【摘要】 粘土砖作为最常见的耐火材料已在冶金、化工等行业获得广泛应用。但粘土砖表面的气孔不仅使材料的强度降低,而且严重影响到材料在冶金工业中的耐磨性和抗熔渣侵蚀性、在化学工业中的耐酸碱性等。然而,CaO-MgO-Al₂O₃-SiO₂系微晶玻璃具有机械强度高、耐磨损、化学稳定好等特性。因此,本文以石英砂、白云石、方解石等天然矿物为主要原料,氟化物为主晶核剂,制备了CaO-MgO-Al₂O₃-SiO₂系统微晶玻璃。然后以微晶玻璃、铝矾土和锆英砂为主要原料,用烧结法在铝质粘土砖表面制备了耐高温耐磨陶瓷涂层,以期改善粘土砖耐火材料表面的耐磨损和抗浸蚀能力。实验表明,晶核剂CaF2能有效促进CaO-MgO-Al₂O₃-SiO₂系统玻璃的晶化。随着CaF₂含量的增加,析晶能力增强,玻璃呈整体析晶。该微晶玻璃的主晶相为透辉石[CaMg（SiO₃）₂]和硅灰石（β-CaSiO₃）。随着配方中CaO/MgO比的降低,所得微晶玻璃中透辉石型晶体含量增加,材料的抗折强度、耐磨性和硬度提高。该陶瓷涂层的主晶相为刚玉（α-Al₂O₃）、锆英石（ ZrSiO₄）和透辉石[CaMg（SiO₃）₂]。微晶玻璃的母体玻璃在1000℃以上熔融,有利于涂层在粘土砖表面铺展和其他组分的扩散,玻璃在冷却过程中会析出透辉石晶相。用光学显微镜观察了粘土砖与涂层的显微结构,发现涂层表面结构致密,没有孔洞与裂纹。该陶瓷涂层的耐火温度高于1400℃,维氏硬度为9-10GPa。更多还原

【Abstract】 As the best common refractories, clay brick is widely used in metallurgy and chemical industries. But a mass of pores existing in the surface of clay brick reduce the strength, and the wear-resisting and corrosion resistance properties. CaO-MgO-Al₂O₃-SiO₂ glass-ceramics is a promising material because of its good wear-resisting, high strength and chemical stability properties. The CaO-MgO-Al2O3- SiO2 glass-ceramics was prepared by melting with quartz, dolomite and calcite as the starting materials and fluoride as nucleation agent. A wear-resistant ceramic coating was prepared on the surface of clay brick using glass-ceramics, bauxite and zircon as the starting materials, in order to improve the wear and corrosion resistant properties of clay brick.Experiments show that CaF₂ can effectively prompt crystallization of the glass. With the increase of CaF₂ content, crystallizing ability of the glass increases. The Avrami exponent indicates one dimensional crystal growth or the bulk crystallization. The major crystalline phases are diopside [CaMg （SiO₃）₂] and wollastonite （β-CaSiO₃）. With the decrease of CaO/MgO, the content of diopside increases, resulting in the improvement of its mechanical properties.The main phases of the ceramic coating are composed of corundum （α-Al₂O₃）, zircon （ZrSiO₄） and diopside [CaMg（SiO₃）₂]. The precursor glass melts over 1000℃, which is helpful for the spreading of the coating and the diffusion of other compositions. The diopside is crystallized from the melted glass during the cooling process. Microstructure of the coating and clay brick was observed by optical microscope. The coating is compact and there are no holes and cracks on the coating. The coating can be used up to 1400℃and has a Vickers hardness of 9-10GPa.更多还原