MgO泡沫陶瓷的制备与性能研究

发布时间：2018-04-29 07:07

  本文选题：显微组织 + 力学性能　； 参考：《南京航空航天大学》2017年硕士论文

【摘要】：氧化镁克服了传统材质泡沫陶瓷过滤器与镁熔体反应的问题,MgO泡沫陶瓷是镁合金液熔炼净化的理想材料。本文针对MgO烧结温度和热膨胀系数高导致其烧结困难和抗热震性较差的问题,采用浆料注模成型方法制备MgO实体陶瓷,研究了Al_2O_3的添加量和烧结温度对MgO陶瓷组织和性能的影响;研究了不同Al_2O_3添加量MgO陶瓷抗镁/铝合金熔体的侵蚀机理;采用有机泡沫浸渍法制备MgO泡沫陶瓷,比较了实验室制备的MgO泡沫陶瓷与铁丝网对镁废料的过滤效果,并对MgO泡沫陶瓷过滤器的过滤机理进行了理论分析。Al_2O_3的添加改善了MgO陶瓷的烧结性能;Al_2O_3与MgO反应生成MgAl2O4分布在MgO陶瓷晶粒的周围,使颗粒间结合紧密并填充孔隙,从而降低气孔率,提升致密度;当Al_2O_3添加量为20%时,在1500℃烧结2h的样品综合性能最好,此时样品的线收缩率为20.93%,体积密度为2.422g·cm 3,气孔率为12.41%,抗弯强度为45.6 MPa;Al_2O_3加入提高了MgO陶瓷的抗热震性,Al_2O_3添加量为10%时,MgO陶瓷的抗热震性最好。随着烧结温度的升高,Al_2O_3添加量为10%的MgO陶瓷孔隙数量和孔隙尺寸下降,陶瓷材料的晶粒尺寸明显增大,且晶粒间结合越来越紧密;烧结温度从1400℃增加到1550℃时,MgO陶瓷的体积密度、体积收缩率和抗弯强度出现增大的趋势,与气孔率的变化趋势相反。不同Al_2O_3添加量的MgO陶瓷材料在镁熔体中是稳定的,侵蚀层与陶瓷材料的原始组织结构相比,气孔较少,致密度提高,阻止了镁熔体进一步向陶瓷材料内部的渗入;没有添加Al_2O_3的MgO陶瓷长时间侵蚀易出现出现裂纹和破碎现象,而Al_2O_3添加量为10%和20%的MgO陶瓷则能保持完整的形态,抗镁熔体侵蚀性能较好。MgO陶瓷材料对氯化物具有很好的吸附效应,侵蚀过程中镁熔体中的氯化物也会侵入陶瓷内部。MgO陶瓷材料在ADC12铝合金熔体中是稳定的,MgO陶瓷材料抗铝合金熔体的侵蚀性能与Al_2O_3添加量和侵蚀时间无关,铝合金熔体不会侵入陶瓷材料内部,没有毛细现象和化学反应发生。聚氨脂泡沫塑料经过碱液处理后,隔膜减少,有效地避免了堵孔现象,表面粗糙度增加,有利于浆料的粘附。实验制得的MgO泡沫陶瓷其气孔率为83%,容重为0.4 g/cm3、抗弯强度为1.08 Mpa、抗热震性较好,可以满足镁合金熔体的过滤。利用MgO泡沫陶瓷过滤实验室镁废料发现,MgO泡沫陶瓷不但对大尺寸杂质具有很好的拦截效果,对尺寸较小的杂质和液态熔剂夹杂和具有很好的过滤和吸附效应。
[Abstract]:Magnesium oxide overcomes the problem of the reaction between the traditional ceramic filter and the magnesium melt. MgO foam ceramic is an ideal material for the purification of magnesium alloy melt. In order to solve the problem that the high sintering temperature and thermal expansion coefficient of MgO lead to the difficulty of sintering and poor thermal shock resistance, MgO solid ceramics were prepared by slurry injection molding method. The effects of Al_2O_3 addition and sintering temperature on the microstructure and properties of MgO ceramics were studied, and the corrosion resistance mechanism of MgO ceramics with different Al_2O_3 contents against melt corrosion of mg / Al alloy was studied, and the MgO foam ceramics were prepared by organic foam impregnation method. The filtration effect of MgO foam ceramics prepared in laboratory on magnesium waste was compared with that of barbed wire. The filtration mechanism of MgO foam ceramic filter was theoretically analyzed. The addition of Al2O3 improved the sintering performance of MgO ceramics. Al2OS3 reacted with MgO to form MgAl2O4 distributed around the grains of MgO ceramics, which made the particles close and filled with pores. When the amount of Al_2O_3 was 20%, the sample sintered at 1500 鈩，

本文编号：1818917