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September 2015 • SMT Magazine 111 Although some of these applications already exist, evolution of such enhanced systems as accelerometers for airbag deployment, angular rate sensors, and communication devices that connect the vehicle to the outside world will rely on new conformal coatings safeguarding the operation of an enhanced digital automobile. For instance, im- proved MEMS technology is expected to soon become com- monplace for many more au- tomotive functions. Popular conformal coat- ings such as those provided by acrylic or epoxy are less suited for automotive purpos- es—moisture can still migrate underneath the circuit board, causing such corrosive and degrading conditions as ex- pansion of the supposedly protected area and subsequent peeling of the protective coat- ing layer from the compo- nent. Since they are not hy- drophobic, acrylic, epoxy and polyurethane conformal coat- ings cannot generate adequate protection for effective use within these heavy moisture environments, typical of automotive systems. Silicone conformal coatings are more wide- ly used in high temperature environments. This attribute has made them a primary choice for many under-hood automotive applications. Unlike acrylics and urethanes, silicones do not vaporize with the application of heat. They further exhibit the capacity of operating effec- tively as more thickly-layered coatings, gener- ating reliable dampening/isolation of excessive engine vibration. This capacity helps the com- ponent function with improved efficiency in a high vibration automotive ecosystem. At the same time, it should not be forgotten that, while hydrophobic to water, silicone con- formal coatings can allow high moisture pen- etration far in excess of even acrylic coatings. Thus, they frequently are rather susceptible to the negative impact of moisture, and associated corrosive elements within the engine. Paralyne coatings offer manufacturers an exceptional range of properties that support ruggedization for numerous products, provid- ing added durability and enhanced perfor- mance. They are recommended for any prod- ucts where reliable, dedicated protection is essential to the performance of elec- trical components and associ- ated automotive ecosystems. For instance, PCBs and simi- lar components benefit from parylene conformal coatings during operation. For ex- ample, parylene pinhole-free coatings conform precisely to the contours of assemblies and components, while im- proving component protec- tion and performance. Regardless of where the protected part is situated, the objective for all conformal coatings will continue to in- clude using environmentally compliant, low-outgassing, solvent-free materials that generate optimal protection and functionality for automo- tive systems. Coatings' value is safeguarding systems' ef- ficient operation under conditions of duress that might otherwise engender diminished per- formance or product failure. Continual devel- opment and refinement of the capabilities of paralyne and other conformal coatings is inevi- table. It should unite effectively with the ongo- ing evolution of automotive digital technology, as well. Doing so will improve the function and security of systems benefiting from conformal coating. smt sean Horn is the vp and cfo at Diamond MT, a premier conformal coating services provider for key industry leaders in the electronics/MeMS, life sciences, industrial, automotive, aerospace and defense markets. regardless of where the protected part is situated, the objective for all conformal coatings will continue to include using environmentally compliant, low-outgassing, solvent-free materials that generate optimal protection and functionality for automotive systems. " " FeAture beNeFIts OF pArALyNe CONFOrmAL COAtINGs IN AutOmOtIve AppLICAtIONs continues