摘要
高温下刚玉质浇注料中铝酸钙水泥结合剂与基体发生反应生成片状六铝酸钙相,可以有效改善材料的抗热震性,但引入过多水泥会产生较大的体积膨胀,从而影响材料性能。为此,采用六铝酸钙骨料部分或全部取代板状刚玉骨料制备浇注料,在确保体积稳定性的同时发挥了六铝酸钙的增韧效应,研究了骨料气孔特性对浇注料养护后和高温处理后材料力学性能的影响,并借助楔形劈裂实验,研究其断裂行为。结果表明,25℃养护下,相比于板状刚玉,六铝酸钙骨料中气孔产生的吸释水效应,促进了在骨料周围生成更多水化产物,加快了水泥水化反应,使骨料与基质间的界面结合更好。经1600℃热处理后水化产物转变成为CA_(6)相,使材料中骨料与基质界面强度提高,且材料断裂过程中裂纹在骨料内扩展的比例增加,结合样品的断裂能和特征长度等参数,浇注料中加入30%CA_(6)骨料时具备最好的抗裂纹扩展能力。
Calcium aluminate cement bond reacts with matrix to form flake calcium hexaluminate phase at a high temperature,thus effectively improving the thermal shock resistance of the material.However,too much cement will produce a large volume expansion that affects the properties of the material.In this paper,calcium hexaluminate aggregate was used to partially or completely replace the tabular corundum aggregate to prepare castable,and the effect of aggregate porosity on the mechanical properties of castable after curing and high-temperature treatment was investigated,and the fracture behavior of castable was analyzed via wedge splitting experiment.The results show that at 25℃,compared with tabular corundum,water absorption and release effect of pores in calcium hexaluminate aggregate promote the formation of more hydration products around the aggregate,accelerate the hydration reaction of cement,and favor the interface meshing between aggregate and matrix.After heat-treatment at 1600℃,the hydration product is transformed into a secondary phase CA_(6),which improves the interface strength of aggregate and matrix,and increases the proportion of crack propagation in aggregate during material fracture.The castable with 30%CA_(6)aggregate has an optimum crack propagation resistance.
作者
陈怡琛
潘丽萍
李亚伟
廖宁
戴亚洁
CHEN Yichen;PAN Liping;LI Yawei;LIAO Ning;DAI Yajie(Wuhan University of Science and Technology,The State Key Laboratory of Refractories and Metallurgy,Wuhan University of Science and Technology,National-provincial Joint Engineering Research Center of High Temperature Materials and Lining Technology,Wuhan 430081,China)
出处
《硅酸盐学报》
EI
CAS
CSCD
北大核心
2022年第12期3293-3304,共12页
Journal of The Chinese Ceramic Society
基金
国家自然科学基金-湖北区域创新发展联合基金(U20A20270)。
关键词
刚玉质浇注料
六铝酸钙骨料
骨料气孔特性
吸释水效应
楔形劈裂实验
corundum castables
calcium hexaluminate aggregate
porosity characteristics of aggregate
water absorption and release
