Similar to the PTF carbon inks conductive silvers are screen defined inks & dry by evaporation to form a tough but flexible film. The principal advantage of silver over carbon conductives is the lower resistance value of silver inks. It should, however, be noted that this comes at a price due to the high (precious metal) silver content.
Typical surface Resistivity at a dry film print thickness of 15µm are:
| XZ250 |
=0.04 O/sq
|
| *It should be noted that by altering the print thickness of the ink the resistance value could be changed. |
XZ250 can additionally be mixed with conductive carbon inks 26-8203 or XZ253 to produce intermediate resistance values.
Typical uses of silver flexible inks include printing circuit tracks for flexible circuits & membranes and printing crossovers between tracks. They can also be used for printing large blocks of ink for applications such as RF Shielding layers.
XZ250 is suitable for use on most substrates. (Coates will shortly be able to offer XZ255 (CHSN8047), it is currently in beta testing at a customer site. XZ255 is has been developed as a high adhesion product specifically for use on Indium Tin Oxide (ITO) coated polyester, the surface of this material makes ink adhesion very difficult. ITO coated polyester is used in the manufacture of electro luminescent displays. Typical surface resistance at a dry film print thickness of 15µm are will be around =0.20 O/sq)
Coates conductive silver inks dry to produce a tough, flexible deposit. As with the carbons the silver inks can be sensitive to some processes used in the manufacture of traditional PCBs. The dried print is sensitive to heat and certain solvents (such as ketones). It should be noted that as with most flexible conductive inks the circuits produced with silver inks are not generally solderable (limited solderability can be achieved by careful processing, although flexibility will be reduced, please contact Coates for more information)
26-8204 Silver Conductive Ink XZ250
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