氧化镧掺杂铌酸钾钠陶瓷的电、光性能研究

Electrical and Optical Property of Lanthanum Oxide Doped Potassium Sodium Niobate Ceramics

铌酸钾钠(K_(0.5)Na_(0.5)NbO_(3),KNN)基陶瓷具有充放电速度快、透明度高、应用温度范围宽、使用寿命长等优点,在脉冲功率器件等领域具有广阔的应用前景。通过改性技术提高铌酸钾钠基陶瓷的电、光性能是该方向的研究热点。本研究采用固相法制备0.825(K_(0.5)Na_(0.5))NbO_(3)-0.175Sr_(1–3x/2)La_x(Sc_(0.5)Nb_(0.5))O_(3)(x=0,0.1,0.2,0.3)陶瓷(简称0.825KNN-0.175SLSN),研究La_(2)O_(3)掺杂对其相结构、微观形貌、光学、介电、铁电及储能性能的影响。研究结果表明:0.825KNN-0.175SLSN陶瓷具有高对称性的伪立方相结构;随着La_(2)O_(3)掺杂量增大,陶瓷的平均晶粒尺寸减小,相变温度(T_(m))及饱和极化强度(P_(max))增大,达到峰值后下降。在x=0.3时,该体系陶瓷表现出优异的透明性,在可见光波长(780nm)及近红外波长(1200nm)范围内透过率分别达65.2%及71.5%,同时实现了310kV/cm的击穿场强和1.85J/cm^(3)的可释放能量密度。

Potassium sodium niobate (K_(0.5)Na_(0.5)NbO_(3),KNN) based ceramics can be widely used for pulsed power systems due to their fast charge-discharge rate,high transparency,wide range of working temperature,and long cycle life.Improving the electrical and optical property of KNN-based ceramics through modification is a research hotspot in this field.0.825(K_(0.5)Na_(0.5))NbO_(3)-0.175Sr_(1-3x/2)La_x(Sc_(0.5)Nb_(0.5))O_(3)(x=0,0.1,0.2,0.3)(0.825KNN-0.175SLSN) ceramics were synthesized by solid state method.The effect of La_(2)O_(3)doping on the phase structure,microstructure,optical property,dielectric property,ferroelectric property and energy storage property of the ceramic was studied.The results indicated that the structure of 0.825KNN-0.175SLSN ceramics was pseudo-cubic phase with high symmetry.With increment of La_(2)O_(3)content,the average grain size of 0.825KNN-0.175SLSN ceramicsdecreased,and the phase transition temperature (T_(m)) and saturation polarization intensity (P_(max)) increased and then decreased.0.825KNN-0.175SLSN ceramics exhibit excellent transparency at x=0.3,the transmittance in the visible wavelength (780 nm) and near-infrared wavelength (1200 nm) ranges reaches 65.2%and 71.5%,respectively.The dielectric breakdown strength of 310 k V/cm and a recoverable energy density of 1.85 J/cm^(3) are achieved at x=0.3.