Abstract Surface enthalpy is an important parameter to predict the phase stability of crystalline materials at the nanoscale, having parametric influence in processes such as coarsening and single crystal nucleation and growth. Yttrium aluminum garnet (Y3Al5O12, YAG) is a base material for solid state laser, with limited thermodynamic information on interfacial energies available. In the present study, we experimentally determined the surface enthalpy of YAG by using microcalorimetry. Nanoparticles were used to maximize the respective measurable heat effect exploiting their intrinsically high surface areas. We further tracked the effect of La or Mg as dopants on the surface enthalpy of YAG. The results indicate that there is a slight reduction in the surface enthalpy of YAG nanoparticles after doping with 2 mol%-La or Mg. The anhydrous surface enthalpy of undoped YAG was measured as 1.28 ± 0.11 J/m2 and was reduced to 0.98 ± 0.09 and 1.11 + 0.07 J/m2 for 2 mol%-La, and Mg doped YAG nanoparticles, respectively, confirming anhydrous surface energies of YAG can be modified by dopants. The effect of water adsorption on the energies, however, show that the differences between doped and undoped YAG surface energies become negligible at relative pressures as low as 20%, challenging surface energy control as a viable process optimization parameter in the presence of humidity.

中文翻译：

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掺杂剂对钇铝石榴石 (YAG) 表面焓的影响

摘要 表面焓是预测纳米级结晶材料相稳定性的重要参数，在粗化、单晶成核和生长等过程中具有参数影响。钇铝石榴石 (Y3Al5O12, YAG) 是固态激光器的基础材料，可用的界面能热力学信息有限。在本研究中，我们通过使用微量热法通过实验确定了 YAG 的表面焓。纳米颗粒用于利用其固有的高表面积来最大化各自的可测量热效应。我们进一步跟踪了 La 或 Mg 作为掺杂剂对 YAG 表面焓的影响。结果表明，掺杂 2 mol%-La 或 Mg 后，YAG 纳米粒子的表面焓略有降低。未掺杂的 YAG 的无水表面焓测量为 1.28 ± 0.11 J/m2，对于 2 mol%-La 和 Mg 掺杂的 YAG 纳米粒子分别降低到 0.98 ± 0.09 和 1.11 + 0.07 J/m2，证实了无水表面能YAG 可以通过掺杂剂进行改性。然而，水吸附对能量的影响表明，在低至 20% 的相对压力下，掺杂和未掺杂的 YAG 表面能之间的差异变得可以忽略不计，这对表面能控制作为存在湿度的可行工艺优化参数提出了挑战。