Skip to main content

One Step Modification of Space-Integrated Systems

Periodic Reporting for period 2 - OSMOSIS (One Step Modification of Space-Integrated Systems)

Reporting period: 2018-04-01 to 2019-07-31

The European Space Sector is facing an imminent crisis. Metal adhesive bonding is a critical process for fabricating satellites and relies heavily on a toxic metal priming process called chromate conversion coating. Environmental legislation (REACH) will prevent the use of the commonly used chromate conversion coatings due to their hazardous nature with sunset dates in 2017 and 2019 for corrosion and primer treatments respectively. Potential replacements may only give a short reprieve from regulation restriction as they are all based on a wet-chemistry approach that is fundamentally tied to the use of aggressive chemicals. Although not currently restricted under REACH regulation, these chemicals are listed as substances of very high concern (SVHC).

The OSMOSIS project aims to utilise the ENBIO patented CoBlast process as a new surface adhesion primer solution. It uses no hazardous chemicals and meets or exceeds existing industry standard performance. CoBlast is already used by ENBIO to apply a qualified thermal control coating for the European Space Agency for spacecraft. The process is highly flexible and can be altered to apply an adhesive primer to replace chromate conversion. The CoBlast adhesive priming process has already passed testing in the automotive sector and is at TRL 6.

The key goal of this project, OSMOSIS, is to bring this adhesive primer solution through full commercialisation within the European Space Sector. Utilising the SME Instrument Phase 2 program enables ENBIO to accelerate their route to market within the 2 year project duration, which would be projected to take up to 5 years without this support. Space Sector adhesion applications have a relatively low process throughput time requirement and very defined part geometries. Once the process has been scaled for the Space sector, it can then be further scaled as a proven technology into the Aerospace and Automotive sectors where they have an identical problem but require faster processing times.

Following extensive product development, a viable process has been demonstrated and benchmarked against existing technologies. Through collaboration with the student-led EIRSAT-1 project, the coating is to see it's first deployment as early as 2020. As such, it has completed a number of qualifications steps including outgassing testing, long term and accelerated storage testing and lap shear testing. Following the last of these qualification tests (vibration testing, scheduled August 2019) an official product launch is planned. The product, dubbed CoBlast SolarPrime, is well-positioned, with excellent results compared to existing technologies, a REACH-compliant status and outlook and a heritage of space use and qualification through the EIRSAT-1 project.

A range of options in terms of customer deployment have been proposed and can be further adapted to customer requirements. This includes a coating service for smaller production runs and on-site coating for larger requirements. A number of promising customer engagements are already underway, with applications for both spacecraft and various terrestrial uses.

It is hoped that this process will replace chromate-conversion processes in aerospace applications. This would be of great benefit to society as chromates have been shown to be carcinogenic, mutagenic and damaging to human fertility.
A range of characterisation equipment was purchased and commissioned. State-of-the-art chromate conversion coated samples were also obtained from aerospace metal finishers.

A CoBlast-deposited adhesive primer was developed. Following various rounds of testing and iterative improvements, the process was demonstrated to be of comparable strengths to state-of-the-art chromate-reliant processes. Extensive lap-shear testing has demonstrated excellent tensile strength of bonded joints following various ageing regimes, again comparable to existing state-of-the-art technologies.

Honeycomb panels, common in aerospace applications, were manufactured using the process and again demonstrated to have equivalent strength to chromic acid anodised counterparts. The coating of these panels also served as a trial production run, indicating the suitability of the process for scaled-up production activities.

During the course of the project, ENBIO supported a student-led ESA Fly Your Satellite activity- EIRSAT-1. This will bring about the first in-flight demonstration of the coating, expected early 2020. It also fulfilled a number of qualification requirements in terms of outgassing testing, vibration testing and thermal cycling. In all cases, the coating has met or exceeded the qualification criteria.

These results and activities were disseminated through various conferences and workshops. Results were also posted to the projects various webpages, including the Enbio website, researchgate and zenodo project pages. Where possible, full open data sets were included. Following these dissemination activities, a number of promising customer engagements are underway. Using feedback from these customer engagements, various coating services and equipment have been proposed and a draft licence agreement put in place. At the project close, one customer has already signed such an agreement.

Further commercialisation and dissemination activities are ongoing, with an official product launch scheduled for September 2019, pending the results of simulated launch (vibrational testing).
"The coating has demonstrated equivalent or improved performance to current state-of-the-art chromic-acid anodisation processes under a variety of conditions. The elimination of these chromate-reliant processes is a priority in the European aerospace community. Initial ""sunset dates"", intended to eliminate their use have already passed. As no suitable, proven alternative existed, these deadlines needed to be pushed out.

Given the coating has undergone a number of qualification activities and is expected to see deployment in short order, it is very well positioned to replace these chromate-based processes. The socio-economic impact of this would be the elimination of the majority of the remaining chromate conversion coating lines within the EU. This would be hugely beneficial as chromates have been proven to be carcinogenic, mutagenic and damaging to human fertility."
Honeycomb Panel undergoing Floating Roller Peel Testing (ASTM D 1781)
Customer sample honeycomb panels- CoBlast and CAA
Initial lap-shear adhesion results comparing State-of-the-Art surfaces to CoBlast adhesive primers
Lap Shear results showing CAA, Grit Blast and CoBlastSolar Prime
Samples being aged in salt-fog chamber
Sample Floating Roller Peel Test (ASTM D 1781) Results