Corrosion Performance and Lacquerability of Passivated Low Tin Coatings

Key Information

Academic Supervisors: Dr Natalie Wint (Primary) and Dr Eifion Jewell

Industry Supervisor: Mark Mainwaring & James Edy

Expected Interview Date: May 2022

Background:

Steel offers an economical and sustainable option for packaging and is used in numerous applications including food, beverage, and aerosol containers. Electroplated tin and chromium has been used for the corrosion protection of steel packaging for over 60 years and offers an effective system. However, with hexavalent chromium being a major component of the electrolyte for tinplate passivation and Electrolytic Chromium Coated Steel (ECCS), the requirements for REACH compliance place many constraints on manufacturers of steel packaging material.

ECCS consists of a chromium coating just 20nm (50mg.m-2) thick and as well as having good corrosion resistance also offers an excellent surface for the adhesion of organic lacquers that are used for additional protection and aesthetics. ECCS is also very economical due to the thin nano-chromium coating. Although trivalent chromium replacements for ECCS are currently in the process of commercialisation there are still strategic questions into other methods of providing suitable corrosion resistance and adequate lacquering of tin mill products as a replacement for ECCS.   The increasing cost of tin and the fact that the lowest coating weight is ~1.0g.m-2 mean a direct swap to tinplate is currently uneconomical.

This project will investigate the use of low tin coatings ( <1.0g.m-2), incorporating a Chromium Free Passivation Alternative (CFPA) treatment,  as an alternative to ECCS without the high capital expenditure required for the construction of a new trivalent chromium coating production lines. The coating will need to provide corrosion resistance, as well as providing a suitable surface on which to apply an organic lacquer overcoat or laminate.

Project Aims:

  • To investigate the corrosion and lacquerability of low tin coating chrome free tinplate (CFPA). 
  • To compare the corrosion performance of free tin CFPA with conventional tinplate that is used in conjunction with a hexavalent chromium pretreatment, as well as with ECCS.
  • Investigate the performance of low Tin coating, chrome free tinplate for laminate applications. 
  • To ascertain the levels to which tin coating weight can be reduced without reducing product performance       

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COATED M2A recognises applicants have a variety of backgrounds with different educational and research experiences. We do not expect applicants to be proficient users of any techniques /equipment mentioned, at the time of application. Our focus is to upskill our participants and training will be provided.

COATED M2A in the Faculty of Science and Engineering is a Swansea University initiative which provides postgraduate research training in partnership with industry, providing access to world class laboratories and a wealth of academic and industry expertise. The M2A is committed to providing top quality research opportunities within an inclusive environment, funded by the Welsh European Funding Office (WEFO), the Engineering and Physical Sciences Research Council (EPSRC), Swansea University and Industry partners.

Interwoven through the research study are business, technical and entrepreneurial courses, designed to support and prepare participants for a senior role in industry or academia, on completion of their studies.

The Athena SWAN charter recognises work undertaken by institutions to advance gender equality. The College of Engineering is an Athena SWAN bronze award holder and is committed to addressing unequal gender representation. Applications from women and other under-represented groups are particularly welcomed. All applications will be anonymised prior to short listing.

Are you considering making an application and have questions you’d like answered? Come and have a 1-2-1 chat with us at our applicant surgeries (Link). We encourage all applicants to review our hints and tips document found here

Sponsoring Company: Tata Steel UK

Eligibility

Candidates must normally hold a minimum undergraduate degree at 2.1 level (or Non-UK equivalent as defined by Swansea University), or a combination of degree and equivalent experience to the same level.

Normally, we would expect candidates to have met the University’s English Language requirements (e.g., IELTS 6.5 overall with 5.5+ in each component) by point of application.

Full eligibility can be found at https://www.materials-academy.co.uk/eligibility

Funding

Fees at UK rate and Stipend £20,000.00, both for the period of four years.

For full details on funding eligibility, please refer to the Materials and Manufacturing Academy (M2A) Website. Student Eligibility | M2A (materials-academy.co.uk/eligibility).

Candidates must have the legal right to live/work in the UK at the start of their studies (student visas do not qualify)

Closing Date: 3rd April 2022

Start Date: 1st October 2022

Applications and informal enquiries about this studentship should be directed by email to:

M2A@swansea.ac.uk