【作者】 刘欣；

【导师】 顾幸勇；

【作者基本信息】 景德镇陶瓷学院 ， 材料学， 2008， 硕士

【摘要】 钛酸铝是一种集低热膨胀耐高温于一体的优质材料,但其强度低和热稳定性差两个致命弱点限制了它的应用。空心球结构具有孔隙率大、密度小、隔热性能好等优点,是制备高性能隔热材料的理想结构。本论文通过对钛酸铝材料进行复合改性,并将其制成空心球结构的新型隔热保温材料。本文通过固相法合成了钛酸铝粉体,探讨了莫来石和镁铝尖晶石等外加剂对钛酸铝材料性能的影响,然后采用滚球法将复合材料滚制成不同孔径的空心球,烧制成空心球隔热砖,利用XRD、SEM、导热系数测试仪、热膨胀系数测试仪和万能材料试验机等测试手段对材料的结构和性能进行了较为深入和系统的研究。制备钛酸铝一莫来石复相陶瓷（ATM）,探讨了莫来石抑制钛酸铝分解和提高强度的机制,研究了莫来石对钛酸铝材料导热系数,抗压强度和热稳定性的影响。结果表明:随着莫来石量的增加,ATM多孔材料的导热系数先变小再增大。ATM多孔材料的强度随着莫来石量的增加呈现上升的趋势,研究发现莫来石加入量在20-30%之间,材料的抗压强度增加最显著。莫来石的加入量以30%为宜,加入量过多会使复合材料的热膨胀系数增加,从而失去很好的热震稳定性。在ATM复合材料的基础配方上,通过外加高强的铝矾土、镁铝尖晶石、刚玉进行增强,考察了外加剂种类和用量对复合材料性能的影响。结果表明,镁铝尖晶石在减少重烧线收缩和降低导热系数的方面效果较明显。外加10%的镁铝尖晶石会使复合材料的导热系数从0.3389w/k.m降低为0.2856w/k.m。采用滚球法工艺制备了空心球多孔砖,研究结合剂的种类和用量、填充细粉的用量、空心球大小配比和烧成制度对空心球砖性能的影响。结果表明:选用5%的Al₂（SO₄）₃和PVA复合结合剂,其抗压强度能达到5.6 MPa。合理的级配有利于大气孔和连续气孔的减少,提高抗压强度。在本研究的实验条件下,大球（直径为2mm）:中球（直径为1mm）:小球（直径为0.5mm）的质量配比为3:4:3是一个较理想的级配。随着烧成温度的提高和保温时间的延长,制品的显气孔率下降,体积密度和抗压强度增加,导热系数也有所上升。最后通过优化工艺与配方,经1500℃保温60min烧成制备出了体积密度为1.27g/cm3、导热率0.1264W/m.k、常温耐压强度可达6.4MPa的轻质隔热砖。更多还原

【Abstract】 Aluminium titanate（AT） has characteristics of high melting point and low thermal expansion coefficient. But AT has two fatal weaknesses of poor thermal stability and low mechanical strength to restrict its application. Hollow ball has characteristics of high porosity, low density and fine heat insulation, so it is the ideal structure to prepare the high perfomance insulation material. In this dissertation ,AT was improved and used to make a new type hollow ball heat insulation material.In this dissertation, AT powder was prepared by solid reaction. The effect of additives, such as mullite and magnesia-alumina spinel on the properties of AT were discussed. The different size of hollow balls were prepared by grounder method and fired into porous insulation tiles. The microstructure and properties were characterized using XRD、SEM、thermal conductivity tester, thermal expansion coefficient tester and materials mechanical properties Tester.AT-Mullite composite ceramics （ATM） was prepared. The mechanism of inhibiting decomposition and improving the strength for AT were investigated and the effect of mullite on the thermal conductivity, compressive strength and thermal stability of AT were studied. As the mullite content increased, the thermal conductivity of ATM decreased first and then increased. The strength of ATM porous material was in an upward trend with the increase of mullite content. The experimentail results indicate that the compressive strength of the ATM porous material increased most significantly when the mullite content was 20-30%. Suitable content of mullite was 30% because too much mullite will result in the increase of thermal expansion coefficient and deterioration of thermal shock resistance.The strength of ATM composite materials was enhanced by addition of bauxite, spinel and corundum. The effect of the type and the amount of additives on properties of composite materials were investigated. The results showed that spinel had the obvious effect on the decrease of the reburning shrink and thermal conductivity. The thermal conductivity coefficient decreased from 0.3389w/m.K to 0.2856 w/m.K by the addition of 10% spinel.Porous tiles with the structure of hollow ball were prepared by grounder method. The effect of the type and amount of binder, fine powder, the proportion of hollow balls and firing system on properties of the porous tiles were investigated .The results showed that 5% of Al₂（SO₄）₃—PVA composite binder can increase compressive strength to 5.6MPa.Resonable proportion was beneficial to the decrease of porosity and increase of compressive strength. In this study conditions,the favorite weight ratio of the balls（diameter of 2mm）to the balls（diameter of lmm）to small balls（diameter of 0.5mm）was 3:4:3. Finally ,with the optimization of production technology and mix-proportion ,the sample after sintered at 1500℃for 60min was with 1.27g/cm3,and its coefficient of heat conductivity 0.1264w/k.m,optimum compressive strength 6.4MPa.更多还原