To investigate the action mechanism of titanium, the effects of different Ti-bearing compounds, including CaTiO3, MgTiO3, and nano-TiO2, on the properties of alumina–magnesia castables were studied. By analyzing the phase compositions, microstructures, and physical and mechanical properties of the castables, it was demonstrated that an intermediate product, CaTiO3, was first generated. This was then consumed by solid-solution reactions, and titanium was involved in the liquid formation as the temperature increased. The solid-solution reaction of CA6 (CaAl12O19) was more prominent due to the incorporation of more titanium in the crystal lattice of CA6 instead of spinel (MgAl2O4). Moreover, the liquid formation was strongly promoted when more titanium accompanied the calcium, which finally accelerated the densification and improved the strengths of alumina–magnesia castables. On the whole, castables with CaTiO3 addition presented higher bulk density and excellent strength after the heat treatment. Besides, the castables with 2 wt.% CaTiO3 contents were estimated to possess greater thermal shock resistance.

中文翻译：

---

添加不同含钛化合物研究钛在氧化铝-镁质浇注料中的作用机理

为了研究钛的作用机理，研究了不同的含钛化合物，包括 CaTiO3、MgTiO3 和纳米 TiO2，对氧化铝-氧化镁浇注料性能的影响。通过分析浇注料的相组成、显微组织和物理力学性能，证明首先生成了中间产物CaTiO3。然后它被固溶反应消耗，随着温度的升高，钛参与了液体的形成。CA6 (CaAl12O19) 的固溶反应更为突出，因为在 CA6 的晶格中掺入了更多的钛而不是尖晶石 (MgAl2O4)。此外，当更多的钛伴随钙时，液体的形成得到了强烈的促进，最终加速了致密化并提高了氧化铝-镁质浇注料的强度。总体而言，添加 CaTiO3 的浇注料在热处理后表现出更高的体积密度和优异的强度。此外，据估计，CaTiO3 含量为 2 wt.% 的浇注料具有更高的抗热震性。