Kolarski Dejan, Lukić Jelena, Janković Jelena, Glišić Sandra
Nikola Tesla Electrical Engineering Institute, 11040 Belgrade, Serbia.
Faculty of Technology and Metallurgy, University of Belgrade, 11000 Belgrade, Serbia.
Materials (Basel). 2025 Aug 12;18(16):3771. doi: 10.3390/ma18163771.
Elemental sulfur (S) reacts readily with silver, forming highly conductive silver sulfide on silver-coated components of on-load tap changers (OLTCs), forming a highly conductive silver sulfide film at the surface of an OLTC, which can lead to the failure of critical components in power transformers. This study investigates the reaction between metallic silver and elemental sulfur dissolved in mineral insulating oil across temperatures from 60 °C to 180 °C. The process involves three stages: the diffusion of sulfur through oil, surface reaction, and product diffusion. For low-viscosity oil, diffusion is not the limiting factor, and sulfur does not react immediately on the silver's surface, suggesting possible adsorption or intermediate formation. A kinetic analysis revealed that the reaction follows first-order kinetics, with a change in mechanism above 150 °C. The reaction follows the Arrhenius equation in two separate regions: 60-150 °C and 150-180 °C. Activation energy was calculated as 23.67 kJ mol, and it can be concluded that the reaction is controlled by the diffusion of sulfur through mineral oil, and at higher temperatures (150 °C to 180 °C), the calculated activation energy is 160.69 kJ mol, which leads to the conclusion that the combined chemisorption and diffusion through a silver sulfide-oil interface becomes the new limiting factor.
元素硫（S）很容易与银发生反应，在有载分接开关（OLTC）的镀银部件上形成高导电性的硫化银，在OLTC表面形成高导电性的硫化银薄膜，这可能导致电力变压器关键部件的故障。本研究考察了金属银与溶解在矿物绝缘油中的元素硫在60℃至180℃温度范围内的反应。该过程包括三个阶段：硫在油中的扩散、表面反应和产物扩散。对于低粘度油，扩散不是限制因素，硫不会立即在银表面发生反应，这表明可能存在吸附或中间产物形成。动力学分析表明，该反应遵循一级动力学，在150℃以上机理发生变化。该反应在两个不同区域遵循阿累尼乌斯方程：60 - 150℃和150 - 180℃。计算得到的活化能为23.67 kJ/mol，可以得出结论，该反应受硫在矿物油中扩散的控制，而在较高温度（150℃至180℃）下，计算得到的活化能为160.69 kJ/mol，这表明通过硫化银 - 油界面的化学吸附和扩散的结合成为新的限制因素。
