Abstract Yttria tetragonal zirconia polycrystalline (3YTZP) ceramic composites with 5, 10 and 20 vol% graphene nanoplatelets (GNPs) were prepared by spark plasma sintering (SPS) and their electrical conductivity as a function of temperature was characterized. The composites exhibit anisotropic microstructures so the electrical conductivity studies were carried out in two directions: perpendicular (σ ⊥ ) and parallel ( σ || ) to the SPS pressing axis. The composites with 5 and 10 GNP vol% showed high electrical anisotropy, whereas the composite with 20 GNP vol% exhibited nearly isotropic electrical behavior. σ ⊥ shows metallic-type behavior in the composites with 10 and 20 vol% GNP revealing that charge transport takes place through defect-free GNPs. For the composite with 5 vol% GNP the observed semiconductor-type behavior was explained by a two dimensional variable range hopping mechanism. σ || shows metallic-type conductivity in the composite with 20 GNP vol% and positive dσ || /dT slope in the composites with 5 and 10 GNP vol%.

中文翻译：

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石墨烯纳米片/氧化钇四方氧化锆复合材料的导电机制

摘要 通过放电等离子烧结 (SPS) 制备了具有 5、10 和 20 vol% 石墨烯纳米片 (GNP) 的氧化钇四方氧化锆多晶 (3YTZP) 陶瓷复合材料，并表征了其电导率与温度的关系。复合材料表现出各向异性的微观结构，因此在两个方向上进行电导率研究：垂直 (σ ⊥ ) 和平行 (σ || ) SPS 压制轴。具有 5 和 10 GNP vol% 的复合材料表现出高的电各向异性，而具有 20 GNP vol% 的复合材料表现出几乎各向同性的电学行为。σ ⊥ 显示了具有 10 和 20 vol% GNP 的复合材料中的金属型行为，表明电荷传输是通过无缺陷的 GNP 进行的。对于具有 5 vol% GNP 的复合材料，观察到的半导体型行为由二维可变范围跳跃机制解释。σ || 显示具有 20 GNP vol% 和正 dσ || 复合材料中的金属型电导率 具有 5 和 10 GNP vol% 的复合材料中的 /dT 斜率。