Complex shapes are created from Yb₁₄MnSb₁₁, a high-temperature thermoelectric Zintl phase, via a two-step process: i) layer-by-layer 3D-extrusion of ink containing partially-reacted powders which are ball-milled from a blend of Yb, MnSb, and Sb powders; ii) heat treatment to synthesize the ternary compound Yb₁₄MnSb₁₁ and densify the extruded powders. A high phase purity for Yb₁₄MnSb₁₁ (83–94%) is achieved in both cast and 3D-extruded ink specimens via a solid-state reaction between Yb, MnSb, and Yb₄Sb₃ during reactive sintering. Pressure-free sintering at temperatures of 1200–1400 °C densifies the powders to 82% relative density but can also induce the decomposition of the Yb₁₄MnSb₁₁ phase due to Yb sublimation. A process window with optimized sintering temperature and time is identified, achieving both low porosity and high phase purity and reaching a maximum zT = 0.61 at 1000 °C, about half of the maximum zT value for bulk Yb₁₄MnSb₁₁ made via conventional processes (pressure sintering of precursor powders). The present approach – direct ink writing of ball-milled powders, combined with reactive sintering – is a scalable and affordable method to fabricate thermoelectric legs with intricate 3D shapes, for enhanced performances in high-temperature thermoelectric applications.

中文翻译：

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用于高温热电材料的 Yb14MnSb11 的油墨铸造和 3D 挤出打印


复杂的形状是由 Yb₁₄MnSb₁₁（一种高温热电锌相）通过两步工艺创建的：i） 含有部分反应粉末的墨水的逐层 3D 挤出，这些粉末由 Yb、MnSb 和 Sb 粉末的混合物球磨而成;ii） 热处理合成三元化合物 Yb₁₄MnSb₁₁ 并使挤出粉末致密化。在反应烧结过程中，通过 Yb、MnSb 和 Yb₄Sb₃ 之间的固态反应，在流延和 3D 挤出油墨样品中实现了 Yb₁₄MnSb₁₁ 的高相纯度 （83-94%）。在 1200–1400 °C 的温度下进行无压烧结可将粉末致密至 82% 的相对密度，但也会由于 Yb 升华而诱导 Yb₁₄MnSb₁₁ 相分解。确定了具有最佳烧结温度和时间的工艺窗口，实现了低孔隙率和高相纯度，并在 1000 °C 时达到最大 zT = 0.61，大约是通过传统工艺（前驱体粉末的压力烧结）制造的块体_{Yb 14MnSb 11} 最大 zT 值的一半。目前的方法——球磨粉末的直接墨水书写，结合反应烧结——是一种可扩展且经济实惠的方法，可以制造具有复杂 3D 形状的热电腿，以增强高温热电应用的性能。