含Sialon的MgO基浇注料流变性、烧结性能和高温性能的研究

【作者】 张殿伟；

【导师】 钟香崇； 马成良；

【作者基本信息】 郑州大学 ， 材料学， 2004， 硕士

【摘要】 本工作的主要研究对象是含非氧化物（矾土基β-Sialon）的MgO基浇注料，探讨了微粉、刚玉细粉和非氧化物（矾土基β-Sialon Sialon）对MgO基浇注料流变性和高温性能的影响规律，以便得出流变性和高温性能较好的MgO基浇注料配比并确定Sialon的合适加入量。 研究工作分四个方面：（1）利用NXS-11A型粘度仪研究微粉、分散剂及Sialon等因素对MgO基浇注料基质流变性的影响；（2）利用跳桌法研究浇注料的流动值并借助浇注料流变仪（IBB Rheometcr V1.0）研究微粉、分散剂及Sialon等对浇注料流变性的影响；（3）研究了微粉、刚玉、Sialon等对热处理后浇注料常规物理性能的影响；（4）利用高温抗折强度（HMOR）、抗热震性（TSR）和抗氧化性分别研究微粉、刚玉、Sialon等对浇注料高温性能的影响。 研究结果表明： 1．对于MgO基无水泥浇注料而言，基质的流变类型符合宾汉姆流体类型。影响基质流变性较大的因素为微粉和分散剂。Al₂O₃微粉对于改善基质流变性的效果不如SiO₂微粉；其中SiO₂微粉加入量不宜超过3％。在本试验所考察的分散剂中三聚磷酸钠的分散效果最好，但其加入量不能超过0.35％。 Sialon的引入对基质的流变性略有负面影响。 2．微粉、分散剂、基质粒度组成、刚玉加入量和Sialon加入量对浇注料的流变性有一定影响。Al₂O₃微粉在加入量不超过4％时对浇注料的流变性几乎没有影响，但加入量超过4％，浇注料的流变性明显变差。增加微粉中SiO₂微粉的比例对MgO基浇注料的流变性有一定的改善，但加入过多改善不明显，综合考虑Al₂O₃／SiO₂微粉比例为50／50左右时对浇注料的流变性较好。三聚磷酸钠加入量在0.35％左右对浇注料分散效果较好。基质中200目与325目细粉的比例不宜超过1：2。刚玉的加入量不能超过15％，否则对浇注料的流变性有较大的负面影响。 Sialon的引入对MgO基浇注料的流变性略有负面影响，但对于浇注料的施工性能影响不大。在本研究范围内，Sialon的加入量不宜超过7.5％。 3．Al₂O₃微粉的加入能够促进浇注料烧结，但加入量应控制在6％以下。SiO₂微粉比Al₂O₃微粉更能促进试样的烧结，但是SiO₂微粉与Al₂O₃微粉的比例不宜超过50／50。 骨料基质比在70／30～60／40的范围内变化对试样的性能影响不大。烧后试样的常温抗折和耐压强度随着基质中325目镁砂的比例的增大略有增大。刚玉的加入使试样产生微膨胀，试样的常温抗折和耐压强度略有提高，但加入量不宜超过巧%。 siaion加入使材料的体积密度略有降低，气孔率略有增大，但1 600℃烧后试样的常温抗折和耐压强度反而随着siaion的增加而略有增大。 4.随刚玉加入量的增加（0¹5%）热震后试样的抗折强度保持率不断提高 （45弘卜J72%）。 随着sialon加入量的增加（小10%），热震后试样的抗折强度保持率不断增加（63叹卜95%），说明siaion的加入有利于提高材料的抗热震性能。 5.本体系的MOF卜T曲线属于I类型。未加sialon的试样Tm（MOR最大值的温度）为600℃，A12O3/s 102微粉比在75/25⁵0/50左右对高温抗折强度最有利。加入sialon后试样的Tm为800℃，并且其强度高于未加sialon的试样，说明sialon的引入对高温力学性能有利。 6.抗氧化剂的抗氧化效果:复合抗氧化剂仍4C复合siC卜siC>金属Al粉. 根据以上结果可知，A120岁51伍微粉比例和分散剂对M夕基浇注料的流变性影响较大.对于本体系而言，最佳的川20岁si伍微粉比为50150，分散剂采用三聚磷酸钠加入t 0.35%左右;刚玉加入量不宜超过15%，当sialon加入量不超过7.5%时对浇注料的流变性影响较小。 加入刚玉（成巧o/o）在Mgo基浇注料中形成了镁铝尖晶石提高了材料的高温性能。适量siaion的引入（毛7.50/0）能够在MgO基浇注料中形成编织结构从而提高了材料的高温性能。对于本体系而言，最适合的抗氧化剂为复合抗氧化剂—B4C复合siC。 综上可知，由于sialon的引入改善了材料的结构，从而提高了材料的性能特别是高温性能。更多还原

【Abstract】 In this work, the influences of ultra fine powders, alumina and bauxite-based ?-Sialon fines on the rheological behaviour and high temperature properties of magnesia-based castables have been studied. The purpose of this work is to find the optimum composition ratio of the castable and appropriate content of Sialon addition.The work can be divided into four parts: (1) The influences of ultra fine powders, dispersants and Sialon fines etc. on rheological behaviour of the castable matrix have been studied by using viscometer of model NXS-11A. (2) The influences of ultra fine powders, dispersants, and Sialon fines etc. on castable rheological behaviour have been studied by using flowing table and IBB Rheometer Vl.O. (3) The influences of ultra fine powders, alumina fines and Sialon fines on the properties at room temperature (such as porosity, bulk density, MOR and CCS etc.) of castables after drying at 110? X 24h and firing at 1100? X 3h and 1600? X3h have been studied. (4) The influences of ultra fine powders, alumina fines and Sialon fines on high temperature properties (such as HMOR, TSR and Oxidation resistance) of castables have been studied.The results show that:1) The rheological behavior of the matrix belongs to Bingham model. Ultra fine powders and dispersants are the principal factors influencing the theology of matrix. Microsilica can improve the matrix rheology more remarkably than ultra fine alumina and the content of microsilica is from 0 to 3%. The dispersant trimeric sodium phosphate can work best among the system and its addition is 0.35% or so.Sialon fines have slightly negative effect on the matrix rheology, which can be offset by using the effective dispersant.2) Ultra fine powders, disperants, the ratio of 200mesh/325mess magnisa fines, alumina fines and Sialon fines can influence the rheological behaviour of the MgO-based castables. Ultra fine alumina has little negative effect on the rheological behaviour of the castable and the content addition is 0-4%. Increasing the ratio of microsilica among the micropowders can improve the rheology of the castable to some degree and the better rheological behavior of the castable can be gained when the ratio of ultra fine alumina to microsilica is about 50:50. Sodium tripolyphosphate can work best with about 0.35% additon.The rheological behavior of the castable can be unproved when the ratio of fine magnesia of 200 mesh to 325 mesh is below 1:2. The addition of fine alumina can contribute to the rheological behavior of the castable with no more than 15% addition.Sialon fines have slightly negative effect on the rheological behaviour of the castable. As to the system studied, the content of Sialon is from 0 to 7.5%.The rheology of the castables can be gently decreased with Sialon addition from 0-7.5%, which has little effect on the applying of the castable.3) Ultra fine alumina can improve the properties of sintering with less than 4% addition. The micro silica is better than ultra fine alumina for the improvement of the properties of sintering, but the ratio of micro silica to ultra fine alumina should not be more than 50/50.It has slightly effect on the properties of sintering when the ratio of the aggregate to the matrix is between 70/30 and 60/40. With the fine magnesia 325 mesh increase, the MOR and CCS increase after heat-treating. The linear changes of the specimens become gently expansive, and the MOR and CCS are gently increased with alumina fines increase from 0 to 15%.The bulk density of the specimens decreases and the porosity increases with the Sialon addition the MOR and CCS of the specimens are increased with Sialon addition after fired in!600? for3h.4) With the increase of alumina fines( 0-15%), the TSR of the specimens is increased (45%-72%).The TSR of the specimens increases (63%-95%) with Sialon addition (0-10%), indicating that Sialon additon can improve the TSR.5) The MOR-T curves of this system belong to the type I.The appropriate ratio of ultra fine alumina to micro silica is 75/25 - 50/50 or so, whic更多还原