Periodic Reporting for period 1 - ECOLAND (Development of ECO-friendly protection procedures for LANDing gear aluminium alloys)
Berichtszeitraum: 2018-03-01 bis 2020-01-31
The topic intended to explore the applicability of anaphoretic electrocoat for aircraft parts made of Al alloys, with the aim of replacement chrome-containing anodizing process, reduction of emissions, saving of cost and improvement of corrosion protection.
The need of using high performance lightweight materials is pushing the aerospace industry to incorporate aluminium alloys in many parts of the aircraft. But all aircraft components, and especially those of landing gears, need to be able to withstand friction and corrosive environments while continuing to operate at optimum levels.
Nowadays most landing gear parts made of aluminium alloys are protected against corrosion by surface anodising and multilayer painting. The treatment is usually carried out on Cr(VI) based compounds. To date, there is not any Cr-free accepted protecting treatment for Al 7000 series alloys that fulfils the aeronautics requirements, so, it is necessary to develop an environmentally and Cr-free acceptable alternative process.
The main objective of ECOLAND project has been to face the research of a suitable REACH compliant anaphoretic electrocoating treatment (including both the optimal pretreatment method and anaphoretic electrocoating application conditions) that can replace the currently used anodising + painting treatment for protection of Al 7000 series alloys in aeronautic applications. This anaphoretic electrocoating will allow apart from the Cr(VI) replacement a reduction of emissions and saving of cost.
The need of using high performance lightweight materials is pushing the aerospace industry to incorporate aluminium alloys in many parts of the aircraft. But all aircraft components, and especially those of landing gears, need to be able to withstand friction and corrosive environments while continuing to operate at optimum levels.
Nowadays most landing gear parts made of aluminium alloys are protected against corrosion by surface anodising and multilayer painting. The treatment is usually carried out on Cr(VI) based compounds. To date, there is not any Cr-free accepted protecting treatment for Al 7000 series alloys that fulfils the aeronautics requirements, so, it is necessary to develop an environmentally and Cr-free acceptable alternative process.
The main objective of ECOLAND project has been to face the research of a suitable REACH compliant anaphoretic electrocoating treatment (including both the optimal pretreatment method and anaphoretic electrocoating application conditions) that can replace the currently used anodising + painting treatment for protection of Al 7000 series alloys in aeronautic applications. This anaphoretic electrocoating will allow apart from the Cr(VI) replacement a reduction of emissions and saving of cost.
In ECOLAND project, a comparative study of the properties, considering aeronautics standards, of two anaphoretic coating systems, has been carried out in Al 7000 alloys. Moreover the comparison of these systems and a chrome-containing anodizing process have been also performed.
The selected e-coatings were an epoxi highly pigmented anaphoretic system (currently approved by some aeronautical companies) and a colloidal polyurethane anaphoretic system (easier for industrial implementation). Process parameters to apply the colloidal anaphoretic system have been also adapted during the project in order to meet the aeronautical standards.
TRL 5 has been achieved during the project. Project technology has been validated in relevant environment. Polyurethane colloidal e-coating with a thin anodising layer have been applied on validation panels and project demonstrators in Cidetec´s pilot plant. Panels have been validated under aeronautical standards.
The results of this work have shown that both, pigmented and colloidal systems, have good adherence, scratch and erosion resistance, chemical resistance, similar fatigue behaviour to the row materialand very good paintability,.
Main Project results are the following four:
• Pre-treatment modified formulations and the pre-treatment method (by CIDETEC)
• Modified anaphoretic e-coating formulations and e-coating method applied on AA7xxx and AA2xxx alloys, to be exploited by LVH Coatings as main seller;
• Coated and tested demonstrators, which will be showed in different fairs and industrial conferences;
• Conclusions from big specimens e-coating, including the environmental and cost analysis. Some of these results will be presented in industrial conferences and published in scientific articles.
The selected e-coatings were an epoxi highly pigmented anaphoretic system (currently approved by some aeronautical companies) and a colloidal polyurethane anaphoretic system (easier for industrial implementation). Process parameters to apply the colloidal anaphoretic system have been also adapted during the project in order to meet the aeronautical standards.
TRL 5 has been achieved during the project. Project technology has been validated in relevant environment. Polyurethane colloidal e-coating with a thin anodising layer have been applied on validation panels and project demonstrators in Cidetec´s pilot plant. Panels have been validated under aeronautical standards.
The results of this work have shown that both, pigmented and colloidal systems, have good adherence, scratch and erosion resistance, chemical resistance, similar fatigue behaviour to the row materialand very good paintability,.
Main Project results are the following four:
• Pre-treatment modified formulations and the pre-treatment method (by CIDETEC)
• Modified anaphoretic e-coating formulations and e-coating method applied on AA7xxx and AA2xxx alloys, to be exploited by LVH Coatings as main seller;
• Coated and tested demonstrators, which will be showed in different fairs and industrial conferences;
• Conclusions from big specimens e-coating, including the environmental and cost analysis. Some of these results will be presented in industrial conferences and published in scientific articles.
For the first time the properties of two anaphoretic systems, an epoxi highly pigmented system (currently approved by some aeronautical companies) and a colloidal polyurethane anaphoretic system, applied to Al 7000 alloys have been compared with a traditional Cr(VI) system following aeronautics standards. Although colloidal systems needs a thin anodising layer their higher stability minimise the risk of sedimentation over the parts which could bring to fail corrosion test.
In general, the main advantages of anaphoretic system against traditional Cr(VI) system include throwing power and environmental issues, cost reduction (labour, materials and electricity, mainly due to primer removal), lead time reduction (mainly due to primer removal), very good throwing power and better adherence with top coat (probably without time limitation between applications). Specifically, the comparative of anaphoretic electrocoatings against chrome-containing processes has shown a 40 % reduction of emissions, 13 % of energy consumption, 30 % of lead time and 21 % of cost saving.
In general, the main advantages of anaphoretic system against traditional Cr(VI) system include throwing power and environmental issues, cost reduction (labour, materials and electricity, mainly due to primer removal), lead time reduction (mainly due to primer removal), very good throwing power and better adherence with top coat (probably without time limitation between applications). Specifically, the comparative of anaphoretic electrocoatings against chrome-containing processes has shown a 40 % reduction of emissions, 13 % of energy consumption, 30 % of lead time and 21 % of cost saving.