Abstract

TiO₂ (titania) nanoparticles (NPs) were successfully synthesized by the sol–gel route with different calcination temperature varied from 300 to 500 °C. The microstructure and morphology of the synthesized samples were characterized under the effect of changing the calcination temperature using X-ray diffraction (XRD) and high-resolution transmission electron microscope (HRTEM). The result obtained from such characteristic tools confirmed the formation of the anatase phase for all the synthesized titania NPs with pronounced dependence of size and agglomeration of particles on the used calcination temperatures. Various nanofluids systems from a commercially mineral oil and the synthesized TiO₂ NPs were fabricated with different concentrations up to 5 g/L from each of the synthesized NPs. The dielectric properties of the fabricated nanofluids were examined by studying the effect of the concentration of titania NPs on the variation of ac breakdown voltage and dielectric constant (ε′). All the prepared oil transformer-nanofluid based on the investigated concentrations of the synthesized TiO₂ NPs exhibited enhancement in the ac breakdown voltage reaching 111.8% for nanofluid with concentration 0.7 g/L based on T400 sample more than that obtained for the pure oil transformer. The dependency of ε′ on NPs concentration was studied under different applied frequency values from 30 Hz to 1 MHz. The nanoparticle features were reflected on the behavior of ε′ with NPs concentration throughout the investigated range of the applied frequency.

中文翻译：

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将不同尺寸的二氧化钛纳米颗粒加载到变压器油中：介电行为的研究

摘要

TiO ₂（二氧化钛）纳米颗粒（NPs）通过溶胶-凝胶法成功地合成，煅烧温度从300到500°C不等。利用X射线衍射（XRD）和高分辨率透射电子显微镜（HRTEM），在改变煅烧温度的影响下，表征了合成样品的微观结构和形貌。从这些特征性工具获得的结果证实，所有合成的二氧化钛NP均形成锐钛矿相，且尺寸和团聚明显取决于所用煅烧温度。来自商业矿物油和合成的TiO _2的各种纳米流体系统从每个合成的NP制备浓度高达5 g / L的NP。通过研究二氧化钛NPs浓度对交流击穿电压和介电常数（ε'）变化的影响，检查了制成的纳米流体的介电性能。基于所研究的合成TiO _2的浓度，所有制备的油变压器-纳米流体相对于纯油变压器，NPs表现出的纳米流体交流击穿电压提高了111.8％，基于T400样品的浓度为0.7 g / L。研究了在30 Hz至1 MHz的不同应用频率下ε'对NPs浓度的依赖性。在整个研究频率范围内，纳米粒子的特征反映在ε'的行为与NPs浓度之间。