Surface Engineering

The REINTEGRA project is one year into its goal of recycling light Al-Li alloys from aircraft.

The constant growth of the aeronautical sector experienced in recent decades has brought with it a problem of waste generated by the end of the aircraft’s useful life, which responds to the sector’s high quality requirements, leading to what are now known as aircraft graveyards.

With the aim of turning this problem into an opportunity, CIDETEC Surface Engineering participates in the European project REINTEGRA, funded within the framework of the CleanSky 2 programme and led by the metallurgical centre Azterlan. During the project, which began in July 2020 and will end in April 2023, new methods are being developed to recover lightweight metal alloys from welded aircraft structures that have already been permanently parked.

REINTEGRA will investigate different separation and pickling strategies for welded panels composed of different 3rd generation aluminium-lithium (Al-Li) alloys in order to demonstrate that they can be re-smelt into alloys of the same family, minimising separation steps during aircraft dismantling.

CIDETEC Surface Engineering is working on the development of chemical and mechanical pickling processes to remove paint coatings and surface treatments applied on aircraft fuselage for aesthetic and anti-corrosion purposes. This will prevent the production of impurities in the re-smelting process, which would not allow recyclability in high value-added alloys.

This research will lead to new dismantling and recycling processes that will be tested on welding coupons and demonstrator panels. The separated metal fractions will be processed in a pilot smelting plant to produce ingots that will undergo various advanced characterisation tests. This will allow the assessment of the efficiency of the process in terms of cost, environmental impact and effectiveness.

The AMANECO project is investigating a process to reduce roughness on aircraft heat exchangers, whose complex geometry is not accessible via mechanical methods.

The aeronautical industry has always been defined by its high-quality standards, as one of the sectors that has been most committed to the possibilities offered by additive manufacturing (AM), solving challenges that traditional methods could not cover.

In this sense, the AMANECO project is developing AM heat exchangers, opening up a new horizon of possibilities in terms of shape, weight and efficiency, making it possible to reduce aircraft costs as well as their consumption.

The geometrical complexity of the exchangers and their difficult accessibility in certain areas of the part means that, once manufactured, it is not feasible to reduce their surface roughness via mechanical polishing processes or electrochemical methods. To overcome this difficulty, CIDETEC Surface Engineering is developing a chemical post-processing method for surface improvement, valid for parts with internal channels and thin walls manufactured by AM.

The project, coordinated by Lortek, is part of the Clean Sky 2 framework and has been conceived under the supervision of the company SAFRAN, and is expected to be completed in 2022.