A direct selective laser sintering (SLS) process was combined with a laser preheating procedure to decrease the temperature gradient and thermal stress, which was demonstrated as a promising approach for additive manufacturing of BaTiO₃ ceramics. The phase compositions in BaTiO₃ ceramics fabricated by SLS were investigated by X‐ray and neutron diffractions. The surface morphologies and cross‐section microstructures were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). A dense hexagonal h‐BaTiO₃ layer was formed on the surface and extended to a depth of 500 μm, with a relative density higher than 97% and absence of pores or microcracks. SLS resulted in the formation of the high‐temperature phase, h‐BaTiO₃, which was retained at room temperature possibly due to the high cooling rate. The grain boundaries of SLSed h‐BaTiO₃ ceramics consist of a Ti‐rich secondary phase. Compared with that of the pressureless sintered t‐BaTiO₃ ceramics, the Vickers hardness of SLSed h‐BaTiO₃ is 70% higher.

中文翻译：

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六方晶钛酸钡陶瓷的直接选择性激光烧结

直接选择性激光烧结（SLS）工艺与激光预热程序相结合以降低温度梯度和热应力，这被证明是增材制造BaTiO ₃陶瓷的一种有前途的方法。通过X射线和中子衍射研究了SLS制备的BaTiO ₃陶瓷中的相组成。通过扫描电子显微镜（SEM）和透射电子显微镜（TEM）对表面形貌和横截面显微结构进行了表征。在表面上形成了致密的六角形h-BaTiO ₃层，并延伸到500μm的深度，相对密度高于97％，并且没有孔或微裂纹。SLS导致高温相h-BaTiO的形成_{如图3所示}，其可能由于高冷却速率而保留在室温下。SLSed h-BaTiO ₃陶瓷的晶界由富钛的第二相组成。与无压力烧结t-BaTiO ₃陶瓷相比，SLSed h-BaTiO ₃的维氏硬度高70％。