Mechanical and electrical properties of PZT ceramics (Zr : Ti=0.40 : 0.60)related to Nd3+ addition

Single phase lead zirconate titanate (PZT) of tetragonal structure (Zr:Ti = 0.40:0.60) was modified using a trivalent rare earth additive Nd2O3. The s amples having composition Pb1-(3x/2)Ndx(Zr0.40Ti0.60)O-3 was prepared by so lid state route. The Nd content in the samples was varied from 0-4 mol %. T he effect of Nd3+ additive on mechanical and electrical properties of PZT c eramics has been studied. It was observed that Nd addition results in enhan cement of fracture toughness (K-IC) and Vicker's hardness (H-v) in the samp les, Nd addition also results in substantial increase in dielectric constan t and d(33) piezo coefficient of PZT ceramics. The maximum value of K-IC ob tained is 2.05 Mpam(1/2). Also the peak value of 680 for dielectric constan t and a d(33) of 240 pCN (- 1) is obtained for the same composition. Both t he mechanical and electrical properties seem to peak at 2% Nd3+ addition, w hich makes this composition attractive for actuator and other high pou er u ltrasonic transducer applications. The increase in mechanical properties ha s been attributed the increased tetragonality (c/a ratio) and increase in s intered density with Nd addition. It seems that the ferroelastic domain swi tching is the main contributor to toughening in these ceramics. The increas ed tetragonality with Nd addition results in more work done in domain switc hing and, hence, enhanced toughness. The increase in electrical properties with Nd addition has been attributed to reduction in oxygen vacancies in th e samples. The X-ray and the sintered density results also suggest that at 2 mol % Nd addition, Nd is reaching its solubility limit in PZT system. (C) 1999 Elsevier Science S.A. All rights reserved.