Papers by Keyword: Mechanical Quality Factor

Abstract: The PSZTM ceramics from Pb_0.94Sr_0.06(Zr_0.52Ti_0.48)O₃ doped with 0.1 mol% Mn were prepared by a solid state reaction and. Two different methods were used to calculate the amount of Mn-dopant into PSZT powder. One was calculated rely on B-site precursor represented by B method. The other was computed based on the amount of calcined PSZT called C method. This study was to investigate the effect of the two different calculating formulations of Mn doped PSZT ceramics by B and C methods on phase formation, microstructure, physical and electrical properties. The results were observed that phase identification showed the formation of perovskite structure in both cases. Besides, the mechanical quality factor (Q_m) of the PSZTM ceramics derived from B method was two times higher than those from C method. Nevertheless, the dielectric constant (K), piezoelectric coefficient (d₃₃) and planar coupling coefficient (k_p) of the PSZTM ceramics from B method were slightly lower than those of derived from C method. This could be drawn the conclusion that PSZTM with 0.1 mol% Mn prepared by B method can be used as hard-type piezoelectric material.

Abstract: The effect of manganese doping on microstructure, piezoelectric and electromechanical properties of Pb_0.94Sr_0.06(Zr_0.52Ti_0.48)O₃ (PSZT) ceramics has studied. The PSZT ceramics doped MnCO₃ concentration in the region of 0-1.0 mol% were prepared by a solid-state reaction and conventional sintering process. Phase identification showed the formation of single phase perovskite structure in all compositions. Microstructure and fracture behavior were observed by scanning electron microscopy (SEM). The fracture behavior demonstrated the change of fracture type from trangranular to mix of trans-and inter-granular type with increasing the amount of MnCO₃. Dielectric constant (K), d₃₃ and k_p were increased when higher amount of MnCO₃ was doped. In addition, the mechanical quality factor (Q_m) was highest at 0.1 mol% MnCO₃ doping in PSZT ceramics.

Abstract: Based on similarity principle, cutting modes of turning, milling, grinding etc are equivalent to three load forms of dot, line and face. And three different loads of dot, line and face are applied on the nano-ZrO2 workpiece by three different indenter models of dot, line and face. To one-dimensional ultrasonic vibration system, the influence is studied which is of different load forms and different load magnitudes on acoustic system characteristics of ultrasonic machining. The experimental results show that, the change of loads has little influence on the acoustic system parameters of ultrasonic machining when the load modes on the nano-ZrO2 workpiece are dot and line. And when the load mode is surface contact, the change of loads has significant influence on the acoustic system parameters of ultrasonic machining.

Abstract: The high-power piezoelectric characteristics of lead-free piezoelectric ceramics, based on a bismuth layer-structured ferroelectric, MnCO₃-doped (Sr_0.7Ca_0.3)₂Bi₄Ti₅O₁₈ (abbreviated as SCBT0.3 + Mn x wt%), were studied. SCBT0.3 + Mn x wt% lead-free ceramics showed an extremely high mechanical quality factor (Q_m) of more than 3000 in the (33) vibration mode under small-amplitude vibration. The high-power piezoelectric characteristics of SCBT0.3 + Mn x wt% were measured using the high-power measurement method based on frequency sweep driving under a constant voltage condition. It was found that the vibration velocity v_0-p of SCBT0.3 + Mn 0.2 wt% linearly increased up to approximately 3.0 m/s. Therefore, the Mn-doped SCBT0.3-based ceramics are a promising candidate for lead-free high-power applications.

Abstract: High-power piezoelectric characteristics of (Bi_1/2Na_1/2)TiO₃ (BNT)- and KNbO₃ (KN)-based ceramics at continuous driving were investigated. The selected compositions of BNT- and KN-based ceramics were 0.88(Bi_1/2Na_1/2)TiO₃-0.04(Bi_1/2Li_1/2)TiO₃-0.08(Bi_1/2K_1/2)TiO₃ doped with 0.6 wt% MnCO₃ [BNLKT4-8Mn0.6] and KNbO₃-MnCO₃ 0.8 wt% [KN-Mn0.8] ceramics. It was found that the vibration velocity v_0-P of BNLKT4-8Mn0.6 and KN-Mn0.8 ceramics linearly increased up to approximately 0.8 and 0.6 m/s, respectively. The temperature increases of BNLKT4-8Mn0.6 and KN-Mn0.8 ceramics were approximately 5°C under continuous driving at the vibration velocity of 0.6 m/s.

Abstract: In this investigation, we extend our previous works to improve piezoelectric properties of Pb(Zr,Ti)O₃ ceramics. Modified lead zirconate titanate (PZT) piezoceramics with a composition Zr/Ti=53/47 containing a trace of mixing dopants were prepared by conventional ceramic technology sintering powder compacts. Replacement of (Zr, Ti)⁺⁴ by Nb⁺⁵, Pb⁺² by Sb⁺³ and Mn⁺⁴ in PZT perovskite type solid solutions was accomplished by the creation of cation and anion vacancies. Modified ceramics were explored as a function of firing temperature to acquire exceedingly good piezoelectric characterizations. From the analysis results, calcined at 850°C for 2 h, and then sintered at 1280°C for 2 h, PZT piezoceramic showed the larger dielectric constant er 2013, mechanical quality factor Qm 120 and maximum electromechanical coupling factor kp 0.67. Besides, the bulk ceramic grains distribution were found to be uniform. Furthermore, the sample was found to possess piezoelectric properties, the resonance frequency being about 200 KHz suitable for acoustic sensor.