Microwave-absorbing coatings

Ternary blends of nitrile rubber, EPDM rubber and polyaniline doped with dodecylbenzene sulfonic acid were prepared and tested as a microwave absorbing coating (for radar-absorbing systems for stealth defense systems) [64]. Good absorption was noted between 11 and 12 GHz with the ability to improve lower frequency absorption with increased thickness. Crosslinking... 

The polymer is used in microwave absorbers and as conductive coating with good abrasion resistance for electronic components. Polyaniline is not thermoplastic and cannot be melted or even softened by heat. It is still stable up to about 240° C and starts decomposing at higher temperatures. 

Water absorbs microwave energy about 10 times better than ice. This is apparently due to the crystal structure of ice inhibiting rotation of the water molecules. Distilled water is a polar insulator, and while it absorbs microwave rather well, a 0.5 molal sodium chloride-distilled water solution absorbs 50% more efficiently. Carbon is nonpolar, but its conductivity is such that it is a respectable microwave absorber. In practice, researchers have elucidated many of the principles involved in microwave and RF energy use and one can formulate an ink or coating with these principles in mind, but the ultimate test is the rate at which the formulated product interacts with microwave energies. 

MnFe204 Titania is coated on MnFe204 nanoparticles by hydrolysis of titanium butoxide precursor Preparation of magnetic and microwave absorbing of core-shell structured MnFe204/ri02 nanocomposites [559]... 

Akman O, Kavas H, Baykal A et al (2013) Magnetic metal nanoparticles coated polyacrylonitrile textiles as microwave absorber. J Magn Magn Mater 327 151-158... 

These coatings are used to prevent the transmission of radio frequency interference from sources such as television or computer displays, as antistatic coatings, and to absorb or reflect microwaves. 

Certain reactants, carrier solvents, catalysts and chemically active coatings applied to inert substrates directly absorb microwave energy. 

Oyster tissue, milk powder, wheat flour (total) Digestion of sample with HN03 and heat in closed container in microwave over reduction with SnCI2 and TBP purging of mercury to gold-coated sand absorber to preconcentrate desorption to detector CVAAS 0.84 ng/g 93-111 Vermeir et al. 1989... 

The sintering of PEEK coatings can be achieved by a microwave sintering technique. It has been demonstrated that silicon carbide distributed in the polymer matrix is a good absorber for the microwave... 

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