Report

Teaser, summary, work performed and final results

Periodic Reporting for period 1 - SEALANT (Optimization and scale-up of final sealing of Sulfuric Acid Anodizing employing Design of Experiments.)

Teaser

“Optimization and scale-up of final sealing of Sulfuric Acid Anodizing employing Design of Experiments - SEALANT”, is an initiative which belongs to the 2nd Call for Proposals (CFP02) of the Clean Sky 2 Joint Undertaking.Chromic acid anodizing (CAA) has been extensively...

Summary

“Optimization and scale-up of final sealing of Sulfuric Acid Anodizing employing Design of Experiments - SEALANT”, is an initiative which belongs to the 2nd Call for Proposals (CFP02) of the Clean Sky 2 Joint Undertaking.

Chromic acid anodizing (CAA) has been extensively used during decades in aircraft manufacturing thanks to its excellent performance. In general terms, Chromate is an outstanding corrosion preventative for aluminium. It works extremely well as a soluble inhibitor in cooling water systems, inhibiting pigment in paints and as a component in deoxidiser, conversion coatings and anodised coatings. However, hexavalent chromium is known to be carcinogenic and to cause a wide array of medical problems, including cancer. Consequently, it has been included in the list of substances of several regulation banning or restricting its use such as REACH (European Union regulation concerning the Registration, Evaluation, Authorisation & restriction of Chemicals), and the industry is working towards the replacement of these contaminant products with more enviromental friendly chemical compounds.


SEALANT project arises as a new contribution towards the challenge of avoiding the use of toxic and potentially harmful materials in design, production and maintenance of aircraft.

The project, which lasts two years, has the following main technological objectives:

• To improve the corrosion behaviour of different aluminium alloys subjected to the anodising and sealing under surface treatment free of chromium.
• To define an optimum experimental condition for the sealing process.
• To implement the sealing process in an industrial scale on demonstrators.
• To evaluate the economic cost and the environmental impact of the new process of sealing.

Work performed

Following is the list of worked performed during the first period:

1) Definition of the whole requirements for the process. This covers all the previous steps, the anodization conditions, the sealing conditions and window of parameters to be optimized, and expected quality of results
2) Screening of non-commercial solutions: state-of-the-art analysis and experimental lab testing led to four different alternatives
3) Pre-industrial scale treatement line setup implementation according to the definition of requirements
4) First processing of aluminium alloys with baseline conditions
5) Design of experiment together with statistic tool (ANOVA) for the evaluation of the effect of each component
6) Evaluation of results from salt spray chamber
7) Advanced characterization of anodic layers
8) Advanced characterization for pit criteria definition
9) ECO-Design of the process based on chemical compounds needed

Final results

1) Proposal for non-commercial new sealing technology
2) Batch processing of differente alloys according to the definition of requirements, including sealing technology proposed by topic manager, with preliminary positive results
3) Identification of the chemical compound with major statical effect on sealing process
4) Identification of the most critical step in the sealing process
5) Proposals for reduction of chemical compounds to be used on the formulations

Website & more info

More info: http://index.php/s/H1CMkT7iSBMXUwr.