【作者】 李宁；

【导师】 朱伯铨；

【作者基本信息】 武汉科技大学 ， 材料学， 2009， 硕士

【摘要】 以刚玉细粉、硅微粉、水泥、α-Al₂O₃微粉、凝胶粉、Al₂O₃纳米粉等为原料,分别选用了三聚磷酸钠、六偏磷酸钠、柠檬酸钠、柠檬酸铵、ADW1、ADS3、FS10和FS20等八种分散剂,研究了这些分散剂对刚玉细粉-水泥-硅微粉、刚玉细粉-凝胶粉-α-Al₂O₃微粉和刚玉细粉-凝胶粉-α-Al₂O₃微粉-Al₂O₃纳米粉等三种系统的刚玉质浇注料基质浆体流变学特性的影响。根据浆体流变学特性研究优化了分散剂的选择及加入量,并进行了刚玉质浇注料的试验研究。全文共分为微粉原料浆体的动电特性研究、分散剂对刚玉质基质流变行为研究以及分散剂在浇注料中的应用三个部分。在微粉原料浆体的动电特性研究中,研究了pH值不同时硅微粉、α-Al₂O₃微粉、凝胶粉、Al₂O₃纳米粉4种浆体ζ电位的变化;并分别测定了三聚磷酸钠、六偏磷酸钠、柠檬酸钠、柠檬酸铵、ADW1、ADS3、FS10和FS20等八种分散剂在加入量（w）为0、0.1%、0.2%、0.3%、0.4%、0.5%、0.6%、0.7%、0.8%、0.9%、1.0%时对硅微粉、α-Al₂O₃微粉、凝胶粉、Al₂O₃纳米粉浆体ζ电位的影响,其固相质量分数分别为8%、15.6%、18.75%和3.1%。结果表明:1)α-Al₂O₃微粉、Al₂O₃纳米粉在强酸强碱条件下都有较大的ζ电位值;SiO2微粉在强酸条件下有较大的ζ电位值;凝胶粉在pH值为10.5左右时,ζ电位绝对值最大;2)硅微粉、α-Al₂O₃微粉、凝胶粉、Al₂O₃纳米粉的等电点依次在pH值=1.95、7.78、5.5、8.72;3)三聚磷酸钠、六偏磷酸钠、柠檬酸钠显著提高了SiO2微粉悬浮液的ζ电位;六偏磷酸钠、三聚磷酸钠、FS20、柠檬酸钠、柠檬酸铵对α-Al₂O₃微粉浆体的ζ电位影响较大;凝胶粉悬浮液很稳定,加入任何一种分散剂都不能显著提高该悬浮液ζ电位的绝对值;三聚磷酸钠、六偏磷酸钠、柠檬酸钠、柠檬酸铵、FS20能显著改变Al₂O₃纳米粉颗粒表面的ζ电位,使ζ电位由正值变为负值,其中FS20的效果最显著。在分散剂对刚玉质基质流变行为研究中得出:1)在刚玉细粉-水泥-硅微粉系统中,控制加水量为12%,当采用三聚磷酸钠、六偏磷酸钠等作分散剂时,在其最佳加入量附近,料浆的流变行为表现为典型的假塑型流体,其中FS20的分散效果最显著,其最佳加入量为0.1%⁰.3%;2)在刚玉细粉-凝胶粉-α-Al₂O₃微粉混合浆体中,适量的FS10或者FS10与ADW1、FS10与ADS3的复合分散剂均对该浆体的流变性能有显著影响,在最佳加入量处,添加FS10和FS10与ADW1的复合分散剂的浆体,其流变特性近似于牛顿流体;而添加FS10与ADS3的复合分散剂的浆体的流变特性呈胀性流体;3)在刚玉细粉-凝胶粉-α-Al₂O₃微粉-Al₂O₃纳米粉浆体中,适量的FS10与FS20的复合分散剂或FS10、FS20与ADW1的复合分散剂以及FS10、FS20与ADS3的复合分散剂都对浆体的流变性能有较明显的改善,且复合分散剂的效果比任一种单一分散剂的分散效果要好;其中FS10与FS20的复合分散剂效果最好。试验中还发现,FS10对凝胶粉浆体的分散效果最显著,最佳加入量为1%;FS20对Al₂O₃纳米粉浆体有良好的分散性。将上述研究结果应用于浇注料中,使浇注料的加水量大幅度降低。其中,在刚玉细粉-水泥-硅微粉系统中,选用FS20作为分散剂可显著提高浇注料的流动性:当浇注料的加水量为3.84%时,流动值可达132。由于加水量的降低,使浇注料试样的显气孔率降低,强度增大。FS10对流动性很差的含凝胶粉的刚玉浇注料具有很好的分散、减水效果:当加水量为5%时,可使浇注料试样具有较高的体积密度。FS10与FS20的复合分散剂及FS10、FS20与ADW1的复合分散剂对含纳米粉浇注料均起到明显的分散、减水效果,使浇注料获得较好的物理性能。研究结果表明,FS10与FS20的复合分散剂更适合刚玉质浇注料体系。更多还原

【Abstract】 In this study, tabular alumina powder, microsilica, calcium aluminate cement, reactive alumina, xerogel powder and Al₂O₃ nano–powder were selected as main starting materials, trimeric sodium phosphate, sodium hexametahphosphate, sodium citrate, ammonium citrate, ADS, ADW, FS10 and FS20 were selected as dispersants. The effect of these dispersants on the rheological behaviour of slurries of three corundum-based castables matrix systems including tabular alumina powder - calcium aluminate cement– microsilica system, tabular alumina powder - xerogel powder -α-Al₂O₃ micro powder system and tabular alumina powder - xerogel powder -α-Al₂O₃ micro powder - Al₂O₃ nano–powder system was individually investigated. Based on the research results, the option and addition of the dispersants into different slurry were optimized. The corundum-based castables were tested to confirm the effect of the dispersants. This study include three major parts: electrokinetic characteristics of the micro powder slurries, the effect of dispersants on the rheological behavior of corundum-base matrix slurries and the application of dispersants on corundum based castables.In the study on the electrokinetic characteristics of the micro powder slurries, the change ofζ-potentials of four kinds of slurries including microsilica,α-Al₂O₃ micro powder, xerogel powder and Al₂O₃ nano–powder respectively under different pH were investigated. The effect of different dispersant additions （0, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%） onζ-potentials for four kinds of slurries which including 8% microsilica, 15.6%α-Al₂O₃ micro powder, 18.75% xerogel powder, 3.1% Al₂O₃ nano–powder respectively was studied. The results showed that: 1)ζ-potentials ofα-Al₂O₃ micro powder and Al₂O₃ nano–powder were high under the conditions of both strong acid and strong basicity; microsilica showed highζ-potential under the condition of strong acid; the absolute value ofζ-potential for the xerogel powder was the highest when pH value was 10.5. 2) The isoelectric points of microsilica,α-Al₂O₃ micro powder, xerogel powder and Al₂O₃ nano–powder were reached when pH value were 1.95、7.78、5.5 and 8.72 respectively. 3) The dispersants of trimeric sodium phosphate, sodium hexametahphosphate and sodium citrate can increase theζ-potential of microsilica suspending liquid significantly. The dispersants of sodium hexametahphosphate, trimeric sodium phosphate, FS20, sodium citrate and ammonium citrate had great influence on theζ-potential ofα-Al₂O₃ micro powder slurry. It was found that the suspending liquid of xerogel was very stable, thus, the effect of dispersants on itsζ-potential was very small. The dispersants of trimeric sodium phosphate, sodium hexametahphosphate, sodium citrate, ammonium citrate and FS20 can significantly improve theζ-potential of the surface of Al₂O₃ nano particles; they could make theζ-potential from positive value to negative value. It was found that the effect of FS20 was the greatest. The research results of the effect of the dispersants on the rheological behavior of corundum-based matrix slurries showed that: 1) In the slurry of tabular alumina powder- calcium aluminate cement - microsilica system, when trimeric sodium phosphate and sodium hexametahphosphate were selected as the dispersants and keeping the water addition as 12%, the rheological behavior of this slurry exhibit a typical pseudoplastic fluid model under the condition of optimized addition of the dispersants. It was found that FS20 was the best dispersant for this system and its optimum addition was 0.1⁰.3%. 2) In the slurry of tabular alumina powder - xerogel powder -α-Al₂O₃ micro powder system, the dispersants of FS10, FS10 and ADW1 compound, and FS10 and ADS3 compound all had great influence on the rheological behavior of this slurry. When the addition of FS10 or FS10 and ADW1 compound was optimized, the rheological characteristics was close to Newtonian fluid. However, when the addition of FS10 and ADS3 compound was optimized, the rheological behavior exhibit a typical dilatant fluid model. 3) In the slurry of tabular alumina powder - xerogel powder -α-Al₂O₃ micro powder - Al₂O₃ nano–powder system, the compound dispersants of FS10 and FS20, FS10, FS20 and ADW1 or FS10, FS20 and ADS3 had remarkable influence on the rheological behavior for this slurry, furthermore the effect of compound dispersant was much more effective than single dispersant. It was found that the compound dispersant of FS10 and FS20 was the most effective. The optimized addition of FS10 for xerogel powder dispersion was about 1%. For Al₂O₃ nano–powder dispersion, the most effective dispersant was FS20.Based on the rheological behavior study, the effectiveness of dispersants on corundum-based castables was confirmed. It was found that for the system of tabular alumina - calcium aluminate cement– microsilica, the dispersant of FS20 can significantly increase the flowability of the castables: the flowability value reached 132 when the water addition was 3.84%. The castables sample reached high strength because of water reduction. The dispersant of FS10 had great dispersion effect on the castables system containing xerogel powder: when the water addition was 5%, the bulk density of the castalbe sample was high. The compound dispersants of FS10 and FS20 or FS10, FS20 and ADW1 had effective function of dispersion and water reducing on the nano-powder containing castables. The experiment results confirmed that the compound dispersant of FS10 and FS20 was most effective for the corundum-based castables.更多还原