Connectors

Fretting corrosion is one of the leading causes of connector failure and yet many still remain unaware of what it is or how it can be prevented. Fretting corrosion is the result of micromotion caused by vibration and/or thermal expansion due to heating or cooling cycles. These micromovements wear down through the metal coatings into the base material that then becomes oxidized. As this oxide layer builds up and increases, the oxide film acts as an insulator between the contacts which creates an open circuit resulting in voltage drop across the terminal and ultimately, power failure or signal loss. To minimize fretting wear and keep oxidation at bay, the implementation of a connector grease is key. Connector grease has two primary benefits. First, the grease reduces physical wear between the connecting surfaces as they undergo micromotions and fretting wear. This helps to preserve the layered coatings on the connectors, designed to prevent oxidation and minimize resistance. Second, they insulate the system from the surrounding environment, preventing the build-up of insulative oxide layers which are ultimately responsible for resistance increase and signal loss.

When a contact corrodes, insulative oxides form on the terminal surface which results in increased resistance, signal loss and component failure. The corrosion can also be conductive and builds up to a point where it bridges the distance between two terminals and creates a short circuit. Even with specially designed housings, there is a risk that dust, dirt, or another form of debris could find its way to the contact pin. When this happens, it can interfere with conductivity and lead to a connection that is not solid. Harsh chemicals can also corrode the metal surface and eat away at the pin’s metal plating. Grease creates an environmental barrier to keep dirt and debris away from the contact surface

When connectors are not properly protected against moisture and water intrusion, the contact surface can corrode over time or even cause an instantaneous short circuit. Moisture can take the form of water, detergents, humidity, or salt spray. To protect connectors against water, many engineers design protective housings to keep out moisture. This adds extra time and cost to the design process and may make the connector hard to access if failure were to occur. Connector grease is a cost-effective solution to protect the contact surface from moisture and environmental corrosion. A common misconception surrounding connector grease is that it is absorbs water. Connector grease repels water from the connector surface. Because it is hydrophobic, connector grease stays in place rather than being washed away over time. Additionally, connector grease also prevents current leakage in conductive environments such as water to ensure consistent connectivity.

Increased mating force can cause misalignment during assembly and lead to an incomplete connection or damage to terminals. Increased mating force can cause misalignment and/or wear at the metal plating. For multi-pin connectors, mating forces increase significantly which can create ergonomic and safety issues during assembly. A thin film of lubricant reduces friction to ease mating force by as much as 80 percent.