Tribo materials for space

Tribology in space differs strongly from tribology on earth. Already vacuum itself rules out most solutions used on ground: lubricants evaporate, materials degrade (polymers) or are not corrosion resistant (nitriding steels), most common metallic alloys are subject to strong adhesive wear or cold welding under vibrations, many coatings exhibit much higher friction (e.g. DLC). Hence, selection of material and lubricants in tribological contacts cannot be extrapolated from terrestrial approaches.

Increasing demands to mechanisms in terms of less mass combined with increased performance, raises the need for improvement or even developments of materials, but also coatings and surface treatments. AAC follows those trends and aims to identify current limitations in commercial business and to develop possible solutions. By linking manufacturers with end users, AAC offers to assist by setting up the concepts of the new solution and by testing the prototypes of manufacturers up to qualification. AAC also offers to act as coordinator towards public funds or ESA, i.e. freeing industry from paperwork (proposals and reporting).

As examples AAC is acting in the development of new self-lubricating polymers, like e.g. for cages in ball bearings. AAC has developed a hybrid lubrication concept for gears that enables high efficiency over wide temperature range. To enable also long life, a new nitriding process for PH-steels was established and validated together with a composite MoS₂ coating. AAC is also active in friction materials, i.e. material pairs that offer a certain “medium friction value” in vacuum but also in ambient. All these processes are established at industrial producers, to enable commercial supply chains.