Compatibility of Conformal Coatings with No Clean Flux

This technical report evaluates the compatibility of conformal coatings with no clean flux residues, focusing on their electrical performance, adhesion strength, and environmental durability. The study was conducted by the AIM Research & Development team in collaboration with OEM electronics manufacturers and conformal coating suppliers. It utilized industry standards such as IPC J-STD-004 for Surface Insulation Resistance (SIR) testing and ASTM D3359 for adhesion testing. The report details the testing methodology, which involved various types of conformal coatings, including acrylics, urethanes, silicones, epoxies, and acrylated urethanes. Results indicated that all flux/coating combinations exceeded SIR requirements, with no dendrite formation or corrosion observed. However, challenges related to delamination were identified, particularly with UV-cured coatings. The report emphasizes the importance of selecting coatings with appropriate modulus characteristics to ensure reliability in extreme temperature conditions. Further studies are suggested to assess the long-term performance of these coatings under different environmental stresses.