Advancing Gear Oil Insights - tribofilm and subsurface correlation focusing on ashless versus organometallic chemistries

High performance industrial gear oils range in application and severity of operation across mining and manufacturing through to energy efficient wind turbines where in service reliability and longevity are key to product performance. Here the gear oil has to provide extremely high levels of surface protection to rolling and sliding contacts over a range of environmental operating conditions. Understanding the surface and sub-surface impact of the additive systems in-use is a key requirement to underpin long term product development of new gear oil systems. Research plays a key role in advancing our understanding of the role that new and existing additive technologies and combinations play in severe loading contact conditions and their impact on the initiation of surface and subsurface metallurgical defects.

This PhD project will be run through the Centre for Doctoral Training in Advanced Materials Systems and presents a 4 year PhD opportunity within the International Centre for Advanced Materials (BP-ICAM) at Manchester University. Working alongside a major, global branded lubricant supplier as an industrially sponsored study the student will be charged with investigating the surface mode of action for a range of additive combinations to critique the impact of metallic and ashless (metal free) additive technologies within a range of product platforms and to understand the surface role of the additives in the formation and resilience of the tribofilm. The deliverable will be the ability to predict the surface behaviour and activity in varying tribological contact conditions and relate this performance to the sub-surface metallurgical condition under different lubricants and test conditions.

This project will be interdisciplinary in nature allowing the candidate to develop their skills within a broad research area. Whilst some chemical knowledge is desirable knowledge of mechanical engineering and a willingness to learn and engage in interdisciplinary research will be essential. This would include; tribology, mechanical engineering and testing, metallurgy, surface science, surface and sub-surface analysis and x-ray imaging.

The EPSRC Centre for Doctoral Training in Advanced Metallic Systems was established to address the metallurgical skills
gap, highlighted in several reports [1-3] as a threat to the competitiveness of UK industry, by training non-materials
graduates from chemistry, physics and engineering in a multidisciplinary environment. Although we will have supplied ~140
highly capable metallurgical scientists and engineers into industry and academia by the end of our existing programme,
there remains a demonstrable need for doctoral-level training to continue and evolve to meet future industry needs. We
therefore propose to train a further 14 UK based PhD and EngD students per cohort as well as 5 Irish students per
cohort through I-Form.

Manufacturing contributes over 10% of UK GVA with the metals sector contributing 12% of this (£10.7BN [4,5]) and
employing ~230,000 people directly and 750,000 indirectly. It is estimated that ~2300 graduates are required annually to
meet present and future growth [5]. A sizeable portion of these graduates will require metallurgical expertise and current
numbers fall far short. From UK-wide HESA data, we estimate there are ~330 home UG/PGT qualifiers in materials and
~35 home doctoral graduates in metallurgy annually, including existing AMSCDT graduates, so it is unsurprising that
industry continues to report difficulties in recruiting staff with the required specialist metallurgical knowledge and
professional competencies.

As well as addressing this shortfall, the CDT will also impact directly on the companies with which it collaborates, on the
wider high value manufacturing sector and on the UK economy as a whole, as follows:

1. Collaborating companies, across a wide range of businesses in the supply chain including SMEs and research
organisations will benefit directly from the CDT through:

- Targeted projects in direct support of their business and its future development and competitiveness.
- Access to the expertise and facilities of the host institutions.
- Involvement in the training of the next generation of potential employees with advanced technical and leadership skills
who can add value to their organisations.

2. The UK High-Value Manufacturing Community will benefit as the CDT will:

- Develop the underpinning science and advanced-level knowledge base required by future high technology areas, where
there is high expectation of gross added value.
- Provide an enhanced route to exploitation, by covering the full spectrum of technology readiness levels.
- Ensure dissemination of knowledge to the sector, through student-led SME consultancy projects, the National Student
Conference in Metallic Materials and industry events.

3. The wider UK economy will benefit as the CDT will:

- Promote materials science and engineering and encourage future generations to enter the field, through outreach
activities developed by the students that will increase public awareness of the discipline and its contribution to modern
life, and highlight its importance to future innovation and technologies.
- Develop and exploit new technologies and products which will help to maintain a competitive UK advanced
manufacturing sector, ensure an internationally competitive and balanced UK economy for future generations and
contribute to technical challenges in key societal issues such as energy and sustainability.

References:
1. Materials UK Structural Materials Report 2009
2. EPSRC Materials International Review 2008
3. EPSRC Materially Better Call 2013
4. The state of engineering, Engineering UK 2017
5. Vision 2030: The UK Metals Industry's New Strategic Approach, Metals Forum