Contact resistance at ceramic interfaces and its dependence on mechanical load

Low contact resistance between individual components is important for solid oxide fuel cell stacks if high performance is to be achieved. Several mechanisms may result in high contact resistance, e.g., current constriction due to low area of contact and formation of resistive phases between the components. s study, the importance of current constriction due to limited area of contact at an interface is investigated by comparing the characteristics of contacts between LSM pellets with different surface finish. ad behaviour of the contact resistance has been investigated and a power law dependence between the load and the contact resistance was found. Higher load resulted in lower contact resistance. The power law exponent depended on surface morphology as well as sample history. Polished surfaces generally showed stronger load dependence than unpolished surfaces. ad behaviour of the contact resistance was calculated using a simple model describing the variation of the contact area with load based on the measured surface roughness. Good agreement between the calculations and the experimentally observed resistances was found.