Master Bond MB600S is a silver containing, aqueous based, sodium silicate system used as a coating in situations where the highest level of EMI shielding effectiveness is paramount. Electromagnetic interference (EMI) and radio frequency interference (RFI) are very important issues in the world of electronics. The energy emitted from various sources such as radios, appliances, etc. can interfere with other electronic devices that are made from plastics. Conductive coatings are often applied to the housings of these plastics in order to protect the devices from these types of interferences.
One of the typical ways shielding effectiveness is measured is by attenuation, which refers to the difference of an incoming intensity of a source and its diminution after it passes through the coating. The actual unit of measurement is in decibels (dB). It should be noted that this scale is logarithmic and a difference of 10 dBs indicates ten times the shielding effectiveness (e.g. 40 dBs is ten times as effective as 30 dBs). In general, an effectiveness of 10-30 dBs is considered to be relatively low but still very useful in certain applications. Between 60-90 dBs is considered to be high and 90-120 dBs is exceptional. In general, the higher the frequency, the more rigorous the application. In the gigahertz (GHz) range, obtaining a high dB level is extremely challenging. In examining the data with the MB600S, the test method used was based on IEEE 299, 2006. Aluminum is the reference for this test, which was performed at room temperature. From 1-2 GHz, MB600S was as effective as the aluminum reference with a range of 95-105 dBs. From 2-5 GHz the rating slowly declines from 95 dBs to about 60 dBs. At this point it stabilizes and remains about 60 dBs through 18 GHz. Although, there is a slight spike in effectiveness at around 15 GHz. This detailed information is contained in Figure 1, below. Also, it should be noted that the service temperature range is 0°F to +700°F. The electrical and temperature resistance properties are truly extraordinary.
Aside from the stunning proficiency, the handling is wonderfully simple and safe. It is easy to brush on and being water based, the system is relatively non-toxic. It should be noted that it is possible to spray this system as well, with the proper equipment. If sprayed on, the shielding effectiveness would be even greater than the values given above. MB600S will cure at room temperature in 24-48 hours or in 1-2 hours at 80°C. If curing with heat it is advisable to ramp up the temperature over a 15-30 minute interval to prevent any possible blistering of the material. MB600S can be used in a wide variety of aerospace and electronic applications where superlative shielding effectiveness is desirable.
Product Advantages
- Water based system, relatively non-toxic
- Great temperature resistance
- Stellar shielding effectiveness
- Remarkable thermal conductivity
- Bonds well to a wide variety of substrates
- Highly effective moisture barrier
- Easily applied by brushing
