Copper Invar Copper PCBs
Copper Invar Copper PCBs was introduced into the printed circuit board industry to combat the differing coefficient of thermal expansion encountered when bonding very dissimilar materials together.
In high temperature environments Copper Invar Copper is sometimes use to strengthen the printed circuit board and control expansion.
Invar, also known generically as FeNi36, is a nickel–iron alloy notable for its uniquely low coefficient of thermal expansion . The name Invar comes from the word invariable, referring to its relative lack of expansion or contraction with temperature changes
Copper Invar Copper is a layer of invar which is a nickel containing iron alloy sandwiched in between two layers of copper.
Copper Invar Copper is readily available in the two thicknesses shown below: