KxNa1-xNbO3无铅压电陶瓷的制备工艺分析
Analysis on Fabrication Process of KxNa1-xNbO3 Lead-free Piezoelectric Ceramic
王振林
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作者单位：(重庆理工大学 材料科学与工程学院， 重庆 400054)
中文关键字：无铅； 压电陶瓷； 铌酸钾钠； 固相合成
英文关键字：lead-free; piezoelectric ceramic; (K，Na)NO3; solid-state synthesis
中文摘要：采用固相合成及常压烧结法制备了铌酸钾钠(KNN)无铅压电陶瓷，利用阿基米德排水法测定陶瓷的密度，通过X射线衍射进行陶瓷的物相分析,使用扫描电镜(SEM)观察了陶瓷的表面形貌。分析了相组成、烧结温度和保温时间对陶瓷烧结性能的影响。结果表明：采用固相合成法制备的KNN无铅压电陶瓷为具有钙钛矿结构的固溶体；钾取代立方相NaNbO3中的钠使晶格发生畸变及晶格常数变大，引起了致密度下降、晶粒尺寸增大；在合适的温度范围内，延长保温时间，提高烧结温度有利于晶体的发育与长大；烧结温度过高或保温时间过长，在烧结过程中Na、K元素易挥发从而导致陶瓷致密度下降。
英文摘要：(K，Na)NO3 lead-free piezoelectric ceramics (KNN) were fabricated by solid-state synthesis and sintering at standard pressure. The actual densities of the resultant piezoelectric ceramics were measured by Archimedes' principal， the phase structure was analyzed by XRD， the surface morphologies were observed by SEM. The effects of composition, temperature， heating time on the sintering characteristics were analyzed. The results show that the as-prepared KNN is solid solution with perovskite crystal structure, the replacement of K with Na in cubic NaNbO3 leads to the lattice distortion and the increase of lattice constants resulting in a inclined density and enlarged grain size; the prolonging sintering at elevated temperature within a suitable range facilitates the crystal growth; overheating at high temperature speeds up the evaporation of Na, K and lessens the ceramic densification.