Rigid Flex Architecture against Two Boards and a Connector
Rigid-flex architecture eliminates discrete connector failures and signal discontinuities while reducing assembly labor, justifying higher bare-board costs.
Fretting Corrosion Failure
Interface Degradation
Surface oxidation happens at the contact point of electrical connectors when microscopic movements occur between the mated surfaces. Fretting corrosion failure is the result of small-scale vibration or thermal expansion that repeatedly exposes fresh metal to the atmosphere. This process creates a build-up of non-conductive oxide debris that increases contact resistance and eventually causes intermittent electrical signals.
Chemical Interaction
Base metals like tin or nickel are highly susceptible to this form of wear because they oxidize rapidly when exposed. In a fretting corrosion failure, the debris accumulates in the contact valley, acting as an abrasive that accelerates the wear of the plating. High humidity and industrial pollutants can speed up this chemical reaction, leading to faster failure rates.
Prevention Strategy
Lubricants and high-pressure contact designs help minimize the movement that initiates the damage. Using gold or other noble metal platings provides the best defense against fretting corrosion failure because these materials do not form insulating oxides. Designers specify the contact force and the plating thickness based on the expected vibration levels of the operating environment.
Regular maintenance and the use of anti-corrosion sprays can extend the life of susceptible connectors. Gold plating remains the standard for high-reliability contact surfaces.