When two objects make contact with each other, there's going to be resistance, or friction, between the surfaces. Friction causes wear and affects the performance and operating life of components, so it’s important to minimize it. Although there’s no way to predict friction behavior with 100 percent certainty, understanding the coefficient of friction (CoF) of surface materials is critical when developing mitigation strategies for your parts.
What Is Coefficient of Friction?
CoF is a ratio of the force required to move one material over another to the total force pressing the surfaces together. It's expressed as two numbers: the static friction, or force, needed to start the movement, as well as kinetic friction, or the force required to move the object once it's in motion.
In order to reduce sliding wear caused by friction, you need a strategy to lower CoF, minimizing wear and saving energy since a lower CoF means less force is needed to move the components. Because two surfaces with the same hardness wearing against each other can deteriorate under modest loads, the generally accepted approach is to make one surface harder than the other. Options can range from oil and grease lubricants to advanced surface enhancement coatings.