Influence of the Substrate Hardness on the Rolling Contact Fatigue of WC-17%Co Hardmetal Coatings

The continual demand for higher load capacity, performance and reliability of gears and other components increases also the role of friction and endurable Hertz pressures. Coatings prepared by high velocity oxy-fuel spraying (HVOF) have the potential to serve as a technical solution for increasing the endurable Hertz pressures and decreasing the coefficient of friction between the contact partners for highly loaded components like gears. WC-17%Co coatings have shown in previous studies promising mechanical properties for such applications. To demonstrate the capacity of WC-17%Co coatings the rolling contact fatigue (RCF) behaviour of the with a thickness of 0.1 mm and 0.6 mm, deposited on soft as well as case hardened steel substrates (16MnCr5) were systematically studied including a comparison to the uncoated substrate material in the soft and hardened state. A summary of design aspects under rolling contact fatigue for hardmetal coated components will be discussed studying the surface and subsurface stress distribution.