Abstract The effect of dopants (or additives) on sintering is typically addressed from a mechanistic and diffusivity perspective by focusing on how dopants affect those parameters. However, a comprehensive description of sintering needs to address the role of dopants in the thermodynamics of the system, which affects local chemical potentials driving forces and is, therefore, ultimately linked to the mass transport mechanisms themselves by the thermodynamic extremal principle. In this work, Lanthanum doped Yttria-Stabilized-Zirconia (YSZ) sintering was studied from both kinetics and thermodynamic perspectives to demonstrate the need for those complementary analyses to allow proper processing control. La caused inhibition of both grain growth and densification, which was a result of a change of interfacial energies linked to La segregation as well as of the codependence of coarsening and densification on the grain boundary energy. While La caused a modest decrease in the activation energy for densification, surface and grain boundary energies decreased from 0.95 to 0.70 J/m2, respectively, for YSZ, to 0.80 and 0.41 J/m2 for 2 mol% La-YSZ, indicating an increase in sintering stress. The apparent contradiction between the thermodynamic data and the observed densification trend is attributed to the reduced grain growth that trapped the system in a metastable configuration.

中文翻译：

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致密化和晶粒生长的动力学和热力学：镧掺杂氧化锆的见解

摘要 通过关注掺杂剂如何影响这些参数，掺杂剂（或添加剂）对烧结的影响通常是从机械和扩散的角度来解决的。然而，对烧结的全面描述需要解决掺杂剂在系统热力学中的作用，这会影响局部化学势驱动力，因此最终通过热力学极值原理与质量传输机制本身相关联。在这项工作中，从动力学和热力学角度研究了镧掺杂的氧化钇稳定氧化锆 (YSZ) 烧结，以证明需要进行这些补充分析以进行适当的加工控制。La 引起晶粒生长和致密化的抑制，这是与 La 偏析相关的界面能变化以及粗化和致密化对晶界能量的相互依赖性的结果。虽然 La 导致致密化的活化能适度降低，但表面和晶界能量分别从 YSZ 的 0.95 至 0.70 J/m2 降低至 2 mol% La-YSZ 的 0.80 和 0.41 J/m2，表明增加在烧结应力。热力学数据与观察到的致密化趋势之间的明显矛盾归因于使系统陷入亚稳态配置的晶粒生长减少。对于 YSZ，2 mol% La-YSZ 分别达到 0.80 和 0.41 J/m2，表明烧结应力增加。热力学数据与观察到的致密化趋势之间的明显矛盾归因于使系统陷入亚稳态配置的晶粒生长减少。对于 YSZ，2 mol% La-YSZ 分别达到 0.80 和 0.41 J/m2，表明烧结应力增加。热力学数据与观察到的致密化趋势之间的明显矛盾归因于使系统陷入亚稳态配置的晶粒生长减少。