Dr. Dirk Lars Engelberg

Title: Professor in Materials Performance & Corrosion

Affiliations: Corrosion/MPC/RCRD/Dalton Nuclear

Director Materials Performance Centre (MPC), Line Manager (Hard Materials Group), Corrosion and Protection Centre (CPC)

---------------------------------------------------------------------------------

Industry Education/Experience: I’ve developed my interest in corrosion during my apprenticeship as Electroplater (1991-1994), which I completed in 1994 with a certified industry degree. I then obtained experience as electroplater in the surface finishing industry, initially focusing on precision electroplating of printed circuit boards followed by functional and decorative coating systems (Cu, Ni, Cr, Ag, Au) for engineering application. 

Academic Education: I joined the department of Surface Engineering and Materials Science at Aalen University (HTW Aalen, Germany) from where I graduated with a Diplom-Ingenieur (FH) degree in 2000. Following my move to the Corrosion and Protection Centre (UMIST) I then obtained a MSc in Corrosion Science and Engineering in 2001, and graduated with a PhD on "Grain Boundary Engineering for Intergranular Stress Corrosion Resistance in Austenitic Stainless Steel" under the supervision of Prof. James Marrow (Manchester/Oxford) and Prof. Roger Newman (Manchester/Toronto). In 2005 I joined the Materials Performance Centre (MPC) as Post-Doctoral Research Associate (PDRA) where most of my research was concerned with the effect of microstructure on localised corrosion & stress corrosion cracking in nuclear plant. I was appointed Lecturer in 2010, promoted to Senior Lecturer in 2015, and to Professor in 2020.

Expertise: I have broad expertise in steel metallurgy, microstructure and grain boundary engineering, corrosion/electrochemistry, and the application of in-situ characterisation techniques, including x-ray computed tomography, image analysis, and 2D/3D correlation methods. I have a keen interest in the characterisation of cement microstructure for immobilisation/encapsulation of nuclear waste, leaching behaviour, concrete microstructure and geological disposal application.

During my research I have achieved the first, in-situ, X-ray tomography observations of intergranular stress corrosion cracking in sensitised austenitic stainless steel and sensitised aluminium alloy 5083. These observations form now the basis of a meso-scale crack propagation model to improve stress corrosion cracking resistance.

2022 Invited Presentations & Talks at International Conferences/Workshops

(i) Gordon Research Conference (GRC) in Aqueous Corrosion, July 2022

Title: "Combining Electrochemistry with Advanced Analytical Tools & Techniques – A Case for Localised Corrosion, Hydrogen Embrittlement & Stress Corrosion Cracking"

https://www.grc.org/aqueous-corrosion-conference/2022/

(ii) Keynote – International Congress on Materials Degradation and Protection, Beijing (virtual) - 15-17 Sept. 2022

Title: “Combining Advanced Analytical Tools and Techniques with Electrochemistry – A Case for Corrosion Science & Engineering”

(iii) EuroCorr 2022, Berlin 28.08.-01.09.2022

Mo.29.08. - Talk 1: Determination of local passivation characteristics of pure aluminium 99.5wt% and aluminium alloy 7075-T6 with an electrochemical pen electrode.

Wed.31.08. - Talk 2: (Hussam Attar) Corrosion Performance of MIG and TIG WAAM Grade 2205 Duplex Stainless Steel

Thur.01.09. - Talk 3: Corrosion of Type 316L Stainless Steel Closure Welds in Chloride-Containing Environments Under Low Relative Humidity Exposure

Thur.01.09. - Talk 4: (Dr Sultan Mahmood) Long-term Observation of Atmospheric Corrosion of AA6063 with Assessment of Re-initiation

XCT (X-ray computed tomography) is a technique used extensively to carry out non-destructive analysis of different materials allowing for the development of corrosion to be observed in-situ in situations where such developments may be obscured and difficult to analyse. When AA6063-T5 is exposed to droplets of FeCl₃, it results in a reaction causing the formation of a volumineous corrosion products on the surface. These then often obscure the extent of corrosion, making it difficult to predict the remaing life-time of components. The work reported here aims to study the effect of FeCl₃ on the rate of corrosion, the mechanisms involved and the long term corrosion behaviour of aluminium. This includes looking at the structural integrity of AA 6063-T5 under atmospheric exposure conditions. The influence of the formation of corrosion products on the corrosion rate is investigated over a period of 48 months. The formation and laterial growth of local corrosion sites is elucidated, with assessment of the effect of changes in relative humidity and after re-wetting. The role of temperature and oxygen availability on the corrosion response in such scenarios was also investigated, in-situ. The findings showed that higher temperatures reduce the rate of corrosion. The prescence of oxygen also caused a reduction in the corrosion rates, with clear differences observed after re-wetting the corrosion sites.

(iv) Stainless Steel World, Maastricht 09.2022

Talk: "On-site, Corrosion Measurement of Stainless Steel – Characterising 
Passivity and Weld Tint Performance"

https://stainless-steel-world-event.com/

Local, on-site assessment of the corrosion behaviour of stainless steel can be obtained using a small, portable electrochemical mini-cell. Application of such a miniature, pen-type cell set-up allows microstructure corrosion susceptibility, weld tint behaviour, and the passivation condition to be assessed, ranked, and characterized. Electrochemical corrosion rate measurements can be carried outy at different component surfaces before or after service exposure. The technique was applied to screen different austenitic (grade 304, 316) and duplex stainless steel microstructures (grade 2101, 2205) for their corrosion response.. Measurement were also carried out across a duplex stainless steel weld, highlighting differences in the local corrosion response of the weld cap, heat affected zone and base material.  Electrochemical screening tests have been carried out using both potentio-dynamic and potentio-static polarisation, with Cchallenges to use and apply the technique further will also be discussed.

(v) Duplex Stainless Steel 2022 - Steering Committee, Moderator, Presenter, November 1st & 2nd 2022, Rotterdam, Netherlands

https://stainless-steel-world-duplex.com/

Talk: "Corrosion Testing of Duplex Stainless Steels – A Novel Test Method to Assess and Rank Susceptibility to Localised Corrosion at Ambient Temperature"

The application of a novel bipolar electrochemistry test to rank the corrosion response of stainless steels at ambient temperature is introduced. This method produces a potential gradient across the tested sample, and provides direct access of the full spectrum of anodic-to-cathodic material response. The corrosion behaviour of Types 304L and 316L austenitic stainless steel are compared to Type 2101 lean duplex and standard 2205 duplex stainless steels. The critical pitting potential obtained via 3-electrode potentio-dynamic polarisation and bipolar electrochemistry testing is compared, with changes and differences in pit growth kinetics and pit aspect ratio development discussed. Localised corrosion in the form of selective corrosion of the ferrite phase has been observed in both duplex stainless steels, followed by trans-passive dissolution in lean duplex stainless steel. This new test method can also be further developed to assess material susceptibility towards stress corrosion cracking and hydrogen embrittlement.

Research Projects & Team