Ni2O3掺杂 MgO－CaO 材料的烧结性研究

摘要

In order to improve the sintering properties and to maintain the hot properties of MgO-CaO mate-rials,analytical pure Mg(OH)2 and Ca(OH)2 with mass ratio of 3 1 were ball milled and light burned,and Ni2 O3 was added as dopant (0,0.5%,0.75% and 1%,respectively,in mass),followed by mulling,slaking, ageing,molding,drying,and finally firing at 1 650 ℃ for 3 h.The bulk density and apparent porosity of the specimens were determined,and the specimens were also analyzed by XRD and SEM.The results show that:the sintering densification degree of MgO-CaO material rises as the Ni2 O3 addition increases from 0 to 0.75%,but it decreases when Ni2 O3 addition exceeds 0.75%.Ni2 O3 decomposes into NiO during heating, forming continuous solid solution with MgO.The formation of the solid solution increases the diffusion mobil-ity of Mg2 + and the mutual diffusion rate between Mg2 + and Ca2 +,which promote the grain growth and sin-tering densification of MgO-CaO materials.%为了在不降低 MgO－CaO 材料高温性能的前提下促进其烧结，将分析纯 Mg（OH）2和 Ca（OH）2按31的质量比配料，经球磨、轻烧后，分别掺加0、0．5％、0．75％、1％（w）的分析纯 Ni2 O3，再经混练、消化、困料、成型、烘干后，经1650℃3 h 烧成冷却后，检测烧后试样的显气孔率和体积密度，并进行 XRD 和 SEM分析。结果表明：随着 Ni2 O3引入量从0增加到0．75％（w），MgO－CaO 材料的烧结致密化程度逐渐增大，但超过0．75％（w）后反而减小。Ni2 O3在烧结过程中分解为 NiO，进而与 MgO 形成连续固溶体，增强 Mg2＋的扩散率，促进MgO－CaO 体系中 Mg2＋和 Ca2＋的互扩散，有利于晶粒的生长发育和试样的烧结致密化。