Effect of magnesium content on dielectric properties and corona resistance of Si‐B‐Mg/epoxy resin composites

To improve the dielectric properties and corona resistance of epoxy resins (EPs), the authors designed and synthesized Si‐B‐Mg/EP nanocomposites and investigated the effects of varying the magnesium elemental content on the dielectric properties, breakdown field strength, corona resistance life, volume resistivity and conductive current of Si‐B‐Mg/EP nanocomposites. The experimental results show that when the molar ratio of Si, B, and Mg in the Si‐B‐Mg composite oxide is 18:2:0.125, the composite has the minor dielectric loss and the most extensive corona resistance life of 401.8 min, which is 4.6 times that of the pure EPs. From the experimental results, the introduction of magnesium can effectively improve the dielectric loss and corona resistance of Si‐B‐Mg/EP composites. Highlights Si‐B‐Mg composite oxides were designed and synthesized. Performance analysis of Si‐B‐Mg/EP composites with different magnesium content The introduction of magnesium reduces the dielectric loss of composites. The introduction of magnesium improves the corona resistance life of composites. Si‐B‐Mg/EP composites with both low dielectric loss and high corona resistance. Synthesis of Si‐B‐Mg composite oxides.