In order to seek the optimal mass fraction for the modified pressboards to improve electric ageing resistance ability, the samples modified by nano-TiO ₂ with 1, 3, 5 and 7% mass fractions were made in the lab. The electrical ageing experiments were carried on these samples. The dielectric properties tests, partial discharge (PD) and DC breakdown were executed on the samples to analyse the electrical ageing performance of the cellulose pressboards modified by nano-TiO ₂ . The interface charge accumulation and decay characteristics of the samples were also tested. The nano-TiO ₂ distributions and the surface morphology for the cellulose pressboards aged 0 and 40   h were observed by scanning electron microscope (SEM) to verify the modification effect, and the trap density characteristics of unmodified and modified samples were also described. The permittivity and the conductivity properties of the modified samples are more advantageous than the unmodified ones after electrical ageing. The electrical characteristics of the modified samples are better than the unmodified ones for different electrical ageing stages. The analysis of SEM images and trap distribution give a good verification to the improvement of the modified samples for different ageing stages.

中文翻译：

---

纳米TiO ₂改性压板在不同电老化阶段的电气特性

为了寻求改性压板的最佳质量分数以提高抗电老化能力，在实验室中制备了质量分数分别为1、3、5和7％的纳米TiO ₂改性的样品 。对这些样品进行电老化实验。对样品进行介电性能测试，局部放电（PD）和直流击穿，以分析纳米TiO ₂改性的纤维素压制板的电老化性能 。还测试了样品的界面电荷积累和衰减特性。0和40岁纤维素压纸板的纳米TiO ₂分布和表面形态   通过扫描电子显微镜（SEM）观察h，以验证修饰效果，并且还描述了未修饰和修饰样品的陷阱密度特性。在电老化之后，改性样品的介电常数和电导率特性比未改性样品更有利。对于不同的电老化阶段，改性样品的电特性优于未改性样品。SEM图像和陷阱分布的分析很好地验证了改性样品在不同老化阶段的改进。