Dielectric and Conductive

Coatings of copper or silver (or sometimes a copper/silver alloy) are often used to provide electrical conductivity, often either becoming part of a circuit, or actually becoming the circuit. Other metals and alloys may also be used depending on the conductivity required. Ceramic coatings such as aluminum oxide or alumina/titania are used frequently for their electrical resistivity. Sometimes the resistive coatings (called dielectrics) and the conductive coatings are used together to produce a circuit.

Electrical Conductivity - Resistivity Application Examples
One application results in an aluminum oxide coating on a component, and then a coating of copper on top of the aluminum oxide. This component is used as the base for an automotive alternator. After coating, a circuit is soldered directly onto the copper coating. In a similar application the base plate is made of aluminum. Since aluminum cannot be soldered to, the copper coating is also applied directly onto the aluminum of the base plate, allowing electrical contact to the aluminum by soldering the circuit onto the copper coating. Zinc is sprayed onto plastic enclosures that are to be used in electronic devices. The zinc is then grounded and is used to prevent electronic signals from escaping the plastic enclosure and affecting adjoining equipment with RFI (Radio Frequency Interference) or EMI (Electromagnetic Interference).	Heat Sink, conductive Copper coating over electrically insulating ceramic thermal spray