Controlling the sintering and microstructure of lead-free potassium sodium niobate ((K_1-xNa_x)NbO₃, KNN) ceramics is of primary importance to optimize its piezoelectric / ferroelectric properties. However, sintering dense and monophasic KNN remains a challenge. Here, we prepare KNN ceramics using spark plasma texturing (SPT), a modified spark plasma sintering (SPS) technique, in which uniaxial pressure is applied in an edge-free configuration, allowing ceramics to deform in the radial direction. Densification at low temperatures (1000 °C) and for short times (20 min) is achieved by SPT accompanied by constrained grain growth (average grain size = 1.4 μm), resulting in enhanced piezoelectric properties (d₃₃ = 108 pC N⁻¹ and g₃₃ = 21.2 × 10⁻³ Vm N⁻¹). In addition, and of relevance, SPT KNN ceramics reveal a more homogeneous electrical microstructure postulated to be related with a reduced diffusion and local segregation of defects, resulting in grain cores and shells with more similar capacitances and conductivities. Our work brings new practical understanding to sintering of KNN and demonstrates the potential of alternative densification strategies for improved lead-free dielectrics.

控制无铅铌酸钾钠（（K _1-x Na _x）NbO ₃，KNN）陶瓷的烧结和微观结构对于优化其压电/铁电性能至关重要。但是，烧结致密单相KNN仍然是一个挑战。在这里，我们使用改进的火花等离子体烧结（SPS）技术火花等离子体织构（SPT）制备KNN陶瓷，其中以无边缘配置施加单轴压力，从而使陶瓷在径向上变形。SPT在低温（1000°C）和短时间内（20分钟）致密化，同时伴随晶粒长大受限（平均晶粒尺寸= 1.4μm），增强了压电性能（d ₃₃  = 108 pC N^-1和g ₃₃  = 21.2×10 ^-3 Vm N ^-1）。此外，与此相关的是，SPT KNN陶瓷显示出更均匀的电微观结构，据推测与减少的缺陷扩散和局部偏析有关，从而导致晶粒核和壳的电容和电导率更加相似。我们的工作为KNN的烧结带来了新的实践认识，并展示了替代致密化策略对改善无铅电介质的潜力。