Cristiglio Viviana, Pozdnyakova Irina, Bytchkov Aleksei, Cuello Gabriel J, Jahn Sandro, Zanghi Didier, Brassamin Séverine, Drewitt James W E, Hennet Louis
Institut Laue-Langevin, 38042 Grenoble Cedex 9, France.
Conditions Extrêmes et Matériaux : Haute Température et Irradiation, 45071 Orléans Cedex 2, France.
Materials (Basel). 2024 Dec 17;17(24):6173. doi: 10.3390/ma17246173.
Magnesium aluminates (MgO)(AlO) belong to a class of refractory materials with important applications in glass and glass-ceramic technologies. Typically, these materials are fabricated from high-temperature molten phases. However, due to the difficulties in making measurements at very high temperatures, information on liquid-state structure and properties is limited. In this work, we employed the method of aerodynamic levitation with CO laser heating at large scale facilities to study the structure of liquid magnesium aluminates in the system (MgO)(AlO), with = 0.33, 0.5, and 0.75, using X-ray and neutron diffraction. We determined the structure factors and corresponding pair distribution functions, providing detailed information on the short-range structural order in the liquid state. The local structures were similar across the range of compositions studied, with average coordination numbers of n¯AlO∼4.5 and n¯MgO∼5.1 and interatomic distances of rAlO=1.76-1.78 Å and rMgO=1.93-1.95 Å. The results are in good agreement with previous molecular dynamics simulations. For the spinel endmember MgAlO ( = 0.5), the average Mg-O and Al-O coordination numbers gave rise to conflicting values for the inversion coefficient χ, indicating that the structural formula used to describe the solid-state order-disorder transition is not applicable in the liquid state.
铝酸镁（MgO）（Al₂O₃）属于一类耐火材料，在玻璃和玻璃陶瓷技术中有着重要应用。通常，这些材料是由高温熔融相制备而成。然而，由于在非常高的温度下进行测量存在困难，关于液态结构和性质的信息有限。在这项工作中，我们利用大型设施中的气动悬浮结合CO₂激光加热的方法，使用X射线和中子衍射研究了（MgO）（Al₂O₃）体系中 = 0.33、0.5和0.75时液态铝酸镁的结构。我们确定了结构因子和相应的对分布函数，提供了关于液态短程结构有序性的详细信息。在所研究的成分范围内，局部结构相似，平均配位数n¯Al₂O₃ ∼ 4.5和n¯MgO ∼ 5.1，原子间距离rAl₂O₃ = 1.76 - 1.78 Å和rMgO = 1.93 - 1.95 Å。结果与先前的分子动力学模拟结果吻合良好。对于尖晶石端元MgAl₂O₄（ = 0.5），平均Mg - O和Al - O配位数导致了关于反转系数χ的矛盾值，表明用于描述固态有序 - 无序转变的结构式不适用于液态。
