Master Bond, Inc. has released MB600G, an aqueous-based, sodium silicate system with graphite filler well suited for EMI/RFI shielding applications. Graphite-filled materials are widely used for shielding and static dissipation applications because of the balance of shielding effectiveness and cost.
Shielding effectiveness is most often measured by attenuation. It is defined as the difference of an incoming intensity of the source and its decrease after it passes through the coating. The actual unit of measurement is in decibels (dB). MB600G was tested with aluminum as the reference material based on test method IEEE 299, 2006. Unlike other shielding systems, MB600G shows little variation throughout the 1-18 gigahertz (GHz) range. At 1 GHz, it is 40 dBs, and at 18 GHz it is 45 dBs with the highest reading of 50 at 1.2 GHz and the lowest at 27 dBs at 1.8 GHz. The combination of shielding effectiveness and temperature resistance is impressive with MB600G’s service temperature range extending from 0°F to +700°F. It is also highly effective as a moisture barrier.
In addition to MB600G’s high performance profile, its handling is simple and safe. The system can be brushed on and, being water based, it is relatively non-toxic. It is also possible to spray this formulation with the proper equipment. MB600G will cure at room temperature in 24-48 hours or in 1-2 hours at 80°C. It is available for use in glass jars measured by weight in grams. This coating features a shelf life of 6 months in its original, unopened containers at room temperature.
