PEO COATINGS ON ALUMINUM SUBSTRATES FOR POWER ELECTRONIC MODULES – AN INTEGRATED SOLUTION FOR ELECTRICAL INSULATION AND THERMAL MANAGEMENT
Abstract
Power electronics modules require dielectric layers that withstand high electric fields and dissipate heat. Polymers provide high breakdown strength but low thermal conductivity, while ceramics provide high thermal conductivity but are brittle, costly, and often require adhesive layers that increase thermal resistance. This review examines plasma electrolytic oxidation coatings on aluminum as an integrated dielectric–thermal solution for power electronic modules. It aims to position PEO relative to polymers, structural ceramics, and composite coating systems, with emphasis on the trade-off among dielectric breakdown strength, thermal conductivity, and areal thermal resistance. The formation mechanism and coating architecture are summarized, followed by a comparison with conventional dielectric materials and coating technologies. Composite PEO coatings containing thermally conductive fillers are then assessed, highlighting AlN-filled coatings with reported thermal conductivity up to 3.94 W·m⁻¹·K⁻¹. Critical needs include standardized metrology and reliability validation under humid heat, thermal shock, and power cycling.
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