合闸电阻是断路器重要组成部分，其作用下是在线路合闸中承受电网中的L-C振荡电能转化为热能并释放到外界环境，以达到抑制合闸过电压的。当前在断路器上使用的陶瓷电阻大都依赖从英国摩根公司进口，核心技术有国外公司所垄断。因此，进行碳陶瓷材料合闸电阻的制备与性能研究，生产出高性能的碳陶瓷合闸电阻，对于打破外国垄断、实现国产化，具有重要意义。本文旨在研究制备碳陶瓷合闸电阻的制备，为早日实现国产化开展积极有益的探索。首先，研究英国摩根公司与日本东海高热公司的两种电阻片，对电阻片的微观结构与电力热宏观性能进行测试，得到了两种电阻片表面形貌、物相组成、导电碳材料种类与含量、以及各项性能方面的对比分析结果，构建微观结构与宏观性能之间的联系。摩根电阻片的性能优于东海电阻片，尤其是在力学性能方面，应选择摩根片为开展国产化研究的参考与对标对象。基于对进口片的深度研究，提出了国产化试制的思路，从原料配方、烧结工艺两个方面着手，在微观结构上减小陶瓷的气孔率与晶粒尺寸，提高电阻片的性能。其次，研究合闸电阻片的原料与陶瓷相、导电相的配方，在原料部分对比分析了导电碳材料、氧化铝骨料、粘土原料、莫来石原料，确定了适合合闸电阻制备的原料体系。使用分析纯原料配方体系，确定了合闸电阻原料配方体系：导电碳材料为石墨，使用α氧化铝和高岭土为骨料，配方中陶瓷相高岭土/α氧化铝质量比约为1.14，石墨添加量为陶瓷相总量的13%。最后，研究了无压、放电等离子体和热压烧结三种工艺，无压烧结研究中得出致密化的活化能大于晶粒生长的活化能，确定无压烧结温度为1400℃，制定了最佳烧结曲线。热压烧结、SPS烧结均可提高陶瓷性能，尤其是在热压烧结方式下烧制了与摩根进口片规格相同的试样，热压烧结的样品电阻率9.89Ω·cm、气孔率0.24%、热扩散系数1.76mm2/s、弯曲强度120MPa，优于传统烧结样品。
The closing resistor is an important component of a circuit breaker. Its function is to withstand the L-C oscillation in the power grid during line closing, convert electrical energy into thermal energy, and release it to the external environment to suppress closing overvoltage. The ceramic resistors currently used in circuit breakers mostly rely on imports from British HVR companies, and the core technology is monopolized by foreign companies. Therefore, the preparation and performance research of carbon ceramic material closing resistors, and the production of high-performance carbon ceramic closing resistors, are of great significance for breaking foreign monopolies and achieving localization. The purpose of this article is to study the preparation of carbon ceramic closing resistors, and to explore actively and beneficially for achieving localization as soon as possible.Firstly, study two types of resistor chips from British HVR company and Japanese TKK company. The microstructure and electrical thermal macroscopic properties of the resistance pieces were tested, and comparative analysis results were obtained on the surface morphology, phase composition, type and content of conductive carbon materials, and various properties of the two types of resistance pieces. The relationship between microstructure and macroscopic properties was constructed. The performance of HVR resistors is superior to TKK resistors, especially in terms of mechanical properties. Therefore, HVR resistors should be selected as a reference and benchmark object for domestic research. Based on in-depth research on imported resistance chips, a domestic trial production approach has been proposed, starting from two aspects: raw material formulation and sintering process, to reduce the porosity and grain size of ceramics in microstructure and improve the performance of resistance chips.Secondly, the raw materials for the closing resistor were studied, along with the formulation of ceramic and conductive phases. In the raw materials section, conductive carbon materials, alumina aggregates, clay materials, and mullite materials were compared and analyzed to determine the suitable raw material system for the preparation of closing resistors. By analyzing the pure raw material formula system, the formula system of the closing resistor raw material was determined: the conductive carbon material is graphite, and the α-Al2O3 and kaolin are used as ceramic aggregates, and the mass ratio of ceramic phase kaolin/alumina in the formula is about 1.14, and the amount of graphite added is 13% of the total amount of ceramic phase.Finally, three processes including pressureless sintering, discharge plasma sintering, and hot pressing sintering were studied. In the study of pressureless sintering, it was found that the activation energy for densification was greater than that for grain growth. The pressureless sintering temperature was determined to be 1400 ℃, and the optimal sintering curve was formulated. Both hot press sintering and SPS sintering can improve the ceramic properties, especially when samples with the same specifications as HVR imported sheets are fired under hot press sintering. The sample resistivity of hot press sintering is 9.89 Ω· cm, porosity is 0.24%, thermal diffusion coefficient is 1.76mm2/s, and bending strength is 120 MPa, which is better than traditional sintered samples.
