Effects of La2O3 on sintering of MgO-CaO ceramics: Molecular dynamic simulation and experiments

• Published in: Journal of the European Ceramic Society 2025-04, Vol.45 (4), p.117107, Article 117107
• Main Authors: Dong, Yunjie, Wang, Zhoufu, Ma, Yan, Liu, Hao, Deng, Chengji, Xia, Zhongfeng, Quan, Zhenghuang, Wang, Xitang, Zhang, Ling
• Format: Article
• Language: English
• Subjects: Densification experiment; La2O3; MgO-CaO ceramics; Molecular dynamics; Sintering mechanism
• ISSN: 0955-2219
• DOI: 10.1016/j.jeurceramsoc.2024.117107

The mechanism of the additive La2O3 on the sintering process of MgO-CaO ceramics was investigated by molecular dynamics simulation, and the interfacial reaction and nanoparticles sintering models were established. The simulations demonstrated that MgO and CaO dissolve into La2O3 crystals, creating O2- vacancies around Mg2+ and Ca2+. These vacancies significantly increase the diffusion rate of ions. Meanwhile, the La2O3 shifts the sintering driving force from reducing internal energy to increasing entropy, thereby enhancing the sintering degree of nanoparticles. However, excessive La2O3 introduction prolongs solid solution reaction times and impedes particle-particle contact, negatively affecting sintering densification. Experimental results show that the density of MgO-CaO ceramics initially increases with the addition of La2O3, reaching a peak of 3.43 g/cm³ at 0.3 mol%, before decreasing. This result aligns with the model's predictions regarding the effect of La2O3 addition. Moreover, the established models offer reference for selecting sintering aids in composite ceramics production.