Professor Steve Bull
Cookson Group Chair of Eng Materials

Background

I have been at Newcastle since 1996 when I moved from AEA Technology, Harwell. At the time I moved I was running most of the engineering coatings activities at Harwell and carrying out contract research in a range of areas of Surface Engineering, joining and high temperature oxidation and corrosion. My current focus is on introducing students to advanced materials and manufacturing technologies and carrying out industrially-relevant research in the Surface Engineering/mechanics area - I specialise in the mechanical assessment of submicron coatings and devices. My work bridges the experimental/modelling divide.

Roles and Responsibilities

Royal Academy of Engineering/Leverhulme Trust Senior Research Fellow (2010-2011)
Head of School of Chemical Engineering and Advanced Materials, 2005-2010
Deputy Head of School, 2002-2005
Professor of Surface Engineering, 2002-2008
Cookson Group Chair of Engineering Materials, 2008-

Qualifications

MA PhD (Cantab) 1988

Awards

Tribology Trust Silver Medal 2013

Fellow of the Royal Academy of Engineering 2014 

Previous Positions

AEA Technology, Harwell (1988-1996). Manager of sections conducting contract research in coating technologies, Surface Engineering, dry corrosion and oxidation and joining.
Department of Mechanical, Materials and Manufacturing Engineering, University of Newcastle (1996-2002). Reader in Surface Engineering

Memberships

Member of the Royal Microscopical Society
Member of the Materials Research Society
Member of the American Vacuum Society
Fellow of the Institite of Materials, Minerals and Mining
Fellow of the Institute of Physics
Chartered Engineer 

Informal Interests

Science Fiction, music and creative writing

I started my research career doing contract research at AEA Technology, Harwell. In the eight years I worked for the organisation (1988-1996) I rose to be the head of the coatings and interfaces section, conducting research on all coatings technologies, joining methods and high temperature oxidation. The work involved developing new coating technologies (e.g. ion beam assisted deposition), new coating materials and architectures (e.g. plasma sprayed yttria coatings for resistance to molten metals), improving coating test methods (e.g. controlled scratch testing for adhesion assessment) and assessing coating performance in order to determine design rules and suitability in a range of applications (e.g. tools, gas turbine blades, automotive exhaust pipes and optical fibre furnaces). It was in this period that I became involved in the International Conference on Metallurgical Coatings and Thin films (effectively the spring meeting of the American Vacuum Society), a link which continues to this day and has resulted in me being elected programme chair for the whole conference for the 2010 meeting and General Chair for the 2011 Meeting.  

In the mid 1990s AEA Technology was privatised and I left for Newcastle University in 1996. In the following six years I established a research group focussed on testing and designing with coatings. I took a conscious decision not to invest in coating plant of our own but to work closely with academics in other units and industry on state-of -the-art coating systems, mostly for tribological applications. This decision was driven by my observation that coatings produced under laboratory conditions were often considerably different from those produced in industrial units and the scale-up process was not straightforward or well understood. Since I am very keen to see that my work is useful to industry and can be directly applicable I have focussed it on materials produced at full scale by suppliers. Much of my early work at Newcastle was aimed at solving problems with coatings for tooling and wear parts but I also started to work on coated glass with Pilkington plc who have become a long term supporter of my work. Another focus has been on coatings and surface treatments to improve the contact fatigue resistance of gear steels which has led me to look at fundamental metallurgical investigations of the phase changes in case carburised steel due to contact stress (Martensite decay).  

My current research in Surface Engineering focuses on the mechanical response of coatings and surface treatments and in the last few years I have specialised in the assessment of the properties of very thin (<1micron thick coatings). At Newcastle I have established state-of-the-art nanoindentation facilities in a clean room environment through SRIF funding and taken the pioneering work of Professor Trevor Page in the nanoindentation area to new levels by combining indentation testing, high resolution microscopy and advanced analytic and numerical modelling. As coatings get thinner and deforming volumes get smaller it is essential to have this mix of modelling and experiment to understand results and generate valid design data for nano devices and this is a major focus of my ongoing research work.  

In the last few years I have specialised in the mechanical response of functional materials such as coatings for microelectronic and optics applications. I have used nanoindentation to provide data for constitutive equations for modelling devices such as MOSFETs and MEMS in order to design smaller devices with controlled levels of strain within them. In the case of MOSFETs the generation of tensile or compressive strain in the channel can lead to increases in the mobility of electrons or holes and thus higher speed devices. Such strain can be introduced by the growth of epitaxial silicon/germanium alloy regions and I have developed modelling approaches based on the finite element method for strain engineering in MOSFETs of less than 100nm in channel length. To back this up I have been developing Raman spectroscopic methods for strain assessment at high spatial resolution. I have recently demonstrated for the first time that tip enhanced Raman spectroscopy can lead to measurable signals from <50nm channel length devices based on strained Si/SiGe – this is the highest resolution non-destructive strain measurement technique for such materials.

Projects

Undergraduate Teaching

Process and Product Engineering
Advanced Materials and Processes
Joining Technology
Advanced Manufacturing Technology

Postgraduate Teaching

Tribology and Materials Design
Nanomaterials
Materials and Fabrication
Advanced Manufacturing Technology