Mg掺杂增强CuCrO2陶瓷的电传导及各向异性OACSTPCD

CuCr1-xMgxO2(x=0,0.005,0.010,0.020,0.030,0.040,0.050)polycrystals with c-axis preferred orientation were prepared by solid phase reaction method.The effects of Mg2+doping on the microstructure orientation,electrical properties,and anisotropy of CuCrO2 polycrystals from the vertical and parallel macroscopic in-plane and thickness directions were investigated.The mechanism of Mg doping enhancing the anisotropy of the electrical conductivity in CuCrO2 ceramics was explored.When x≤0.030,the polycrystals exhibit a rhombohedral R3m single-phase structure,with grain growth predominantly occurring within the surface plane.This led to a reduction in the presence of gas pores and grain boundaries,resulting in the increase of density.The polycrystals demonstrated thermally activated semiconductor electrical transport behavior.When x=0.030,the in-plane orientation factor F(00l)reaches its highest value of 0.912,indicating a significantly enhanced c-axis preferred orientation within the surface plane compared to the thickness direction.The room temperature resistivity of CuCr1-xMgxO2 polycrystals in the in-plane and thickness directions decrease significantly to 1.80 × 10 3 and 3.16 ×10-3 Ω·m,respectively.This difference in electrical performance between the two directions was closely related to the structural anisotropy.The thermal activation energy decreased to 0.03 eV,and the c-axis preferred orientation has no significant influence on the thermal activation energy.The maximum carrier concentration increase by three orders of magnitude compared to the parent phase,indicating fewer grain boundary defects,an increased average free path,enhanced transport capacity,and higher conductivity.The experimental results reveal that the optimal doping concentration is x=0.030.When the doping level exceeded 0.030,the spinel phase MgCr2O4 appeared as an impurity,resulting in a deterioration of the microstructure and electrical transport properties of the samples.