Development of new manufacturing processes to substitute cobalt in aircraft components

The NEMARCO European project targets the development of nickel-based components that will be more resistant to wear and to high temperatures, as well as less harmful for human health.

Focused on the eco-design of aircraft components, the newly launched NEMARCO project aims at developing more sustainable, long lasting, and health friendlier materials and processes. Specifically, the research team of this Clean Sky 2 project will work on a new generation of sealing rings for butterfly valves that belong to the cabin pressurisation air purging system, which are currently manufactured in cobalt-based alloys.

The mentioned sealing rings are exposed to high temperatures and significant mechanical loads as well as to a continuous friction due to the movement of the evacuation valves that release the pressure from the circuit. These working conditions are critical in terms of wear resistance and along with it, the risk of leakages as well as the risk of oxidised cobalt particles (which harmful for human health) to reach the cabin atmosphere.

As explained by AZTERLAN researcher Fernando Santos, specialized in advanced metallic materials, “the new UHBR engine involved within this Clean Sky 2 joint challenge will put more pressure and higher temperatures on these components. Therefore the work will be focused on the development of sealing rings manufactured in nickel alloys. We will explore new NiCrSiFeB alloys by adapting current centrifugal casting manufacturing parameters and looking for alternative manufacturing processes such as additive manufacturing by means of LMD”.

In a first phase, a significant design work will be performed by applying modelling methodologies associated to the formation of phases and to the study of the main diffusion and precipitation phenomena. This previous study will allow to select the most suitable chemical compositions and if necessary, to define the thermal processing of the alloy to achieve its optimal behaviour in the final working conditions.

Afterwards, the research team will design experiments for each manufacturing process, gathering the data associated to process variables, the microstructure of the alloy and the hardness of the final product at high temperature conditions. All the data will be processed by creating a predictive model that will identify the optimal manufacturing conditions for the next testing compilation. In a second testing cycle, the new alloys will undergo extensive tribological studies in high temperature that will make it possible to perform a final evaluation of the selected samples from the technical point of view.

Along with a previous technical analysis, a LCA and preliminary toxicity study will be carried out to assess the environmental and economical impact of the new developments. The selected solution must balance the functionality in operation conditions and environmental and health sustainability. Finally, rings will be manufactured by means of two manufacturing processes and will be tested to validate the posed solutions.

NEMARCO project is funded within Clean Sky 2 Joint Undertaking framed within European Union’s Horizon 2020 research and development program, under grant agreement 101007948. The NEMARCO consortium is formed by BRTA members Lortek (project leader), Cidetec and Azterlan Metallurgy Research Centre, along with Miranda de Ebro Technology Centre and the Ecole Centrale de Lyon (France). The project will end in 2022.

NEMARCO Project launch meeting with some of the Consortium researchers