The effect of grain size on crystal structure and the ferroelectric, dielectric, and piezoelectric properties of 0.38Bi(Ni_2/3Ta_1/3)O₃-0.62PbTiO₃ ceramics was studied herein. By controlling the sintering time, 0.38Bi(Ni_2/3Ta_1/3)O₃-0.62PbTiO₃ ceramics with different grain sizes were prepared by the conventional solid-state reaction. It was found that the crystal structure of the ceramics changed slightly with the increase of grain size, from a pure tetragonal perovskite structure to a combination of tetragonal and rhombohedral phases. Both the Curie temperature T_C and the depolarization temperature T_d of the ceramics decreased with increasing grain size. However, the degree of dielectric relaxation first increased and then decreased, with the relaxation factor γ ranging from 1.35 to 1.87. The remnant polarization P_r and coercive field E_C also first increased and then decreased, whereas the strain increased with the increase of grain size. The high field strain coefficient d^*₃₃ and piezoelectric coefficient d₃₃ both increased with the increase of grain size. However, in this ceramic system, the electromechanical coupling coefficient k_p and mechanical quality factor Q_m changed independently of the variation in grain size.

研究了晶粒尺寸对0.38Bi(Ni _2/3 Ta _1/3 )O ₃ -0.62PbTiO ₃陶瓷晶体结构及铁电、介电和压电性能的影响。通过控制烧结时间，采用常规固相反应制备了不同晶粒尺寸的0.38Bi(Ni _2/3 Ta _1/3 )O ₃ -0.62PbTiO _3陶瓷。发现随着晶粒尺寸的增加，陶瓷的晶体结构略有变化，由纯四方钙钛矿结构转变为四方和菱面体相的组合。居里温度T _C并且陶瓷的去极化温度T _d随晶粒尺寸的增加而降低。然而，介电弛豫程度先增大后减小，弛豫因子γ介于 1.35 到 1.87 之间。剩余极化P _r和矫顽场E _C也先增大后减小，而应变随着晶粒尺寸的增大而增大。高场应变系数d ^* ₃₃和压电系数d ₃₃均随着晶粒尺寸的增加而增加。然而，在这个陶瓷系统中，机电耦合系数k _p和机械品质因数Q _m的变化与晶粒尺寸的变化无关。