Women's Month 2023: Chrestinah Surrender Mkhonto

August is Women’s Month, and this year the National Research Foundation (NRF) is celebrating the remarkable contributions that have been made by women researchers for the betterment of humanity. We thank all participants for sharing their stories with us.

Ms Chrestinah Surrender Mkhontoisa PhD Candidate in Physics at the Materials Modelling Centre at the University of Limpopo (UL). She received funding from the NRF for her Master’s studies.

What impact did the NRF have on your studies/career?

I received NRF funding for my Master’s degree. Then I had an outstanding fee balance from my PGCE and Honours degree – it was paid off and cleared at the same time I was receiving the stipend to help me sustain my daily needs every month. That, in turn, helped me to focus on my studies without financial strain or concerns.

What has been your study/career journey?

Science has always been my heart’s desire; to make a significant impact and provide innovative skills in the field of science.

Continuous attendance at annual conferences has been a worthwhile investment throughout my academic career because it is the largest gathering of academic professionals. It gave me room to understand my research in-depth, present gaps and the pros and cons. It also gave me an opportunity to make my research more effective by implementing new/rarely used computational techniques which keep the percentage error very minimal yet applicable.

My pursuit came from a background of overcoming gender-based inequality, in particular, my origin where women are reduced to housework, schools without science equipment to promote science, and a high pregnancy rate which causes young learners to be despondent for there is a lack of information about funding opportunities.

This has been my encouragement in releasing publications (four to five), a platform to make my work known, which offered me awards in various science organisations for best work done (about seven awards). Since I pursued my postgraduate studies in 2014, I became even more inspired by these achievements and that what I am doing is relevant, and so I became part of other women’s associations both at university and secondary level (about five associations). My path came through a PGCE route, however, I did not allow that to be a hindrance for I kept on pressing until a door of opportunity opened for me to be part of the science field directly.

What is your research focus on/what is your area of expertise?

Transition-metal alloys such as iron-aluminides exceed Ni-based superalloys in a variety of industrial sectors because of their unique corrosion properties and resilience to high-temperature oxidation. Because of their extraordinary resistance to oxidation at high temperatures, Fe-Al-based materials have recently received a lot of attention as potential steel substitutes. Previous research has shown that increasing the Al concentration reduces the density of materials and, as a result, improves the protective oxide layer at high temperatures.

These systems are easily influenced by environmental effects and limited by their tendency for low-temperature fracture and decreased ductility. This fracture resistance is influenced by the possible crack on the surface as a result of low free surface energy. Thus, the investigation of surface stability and interaction with either oxygen or water will provide knowledge and understanding of the strength and oxidation behaviour of the Fe-Al systems at higher temperatures.

Iron aluminides-based alloys are promising candidate materials for high-temperature applications due to their ability to significantly enhance ductility through better control of composition and microstructures. These alloys are capable of forming steel components with increased strength, ductility, toughness; much resistance to environmental embrittlement, and high-temperature gaseous conditions. Various investigations were done on the Fe-Al systems to determine their competency in turbines, automotive parts and industrial paint coatings engineered with stainless steel for superior protection. Their investigation has shown that they are promising materials to improve coating on stainless steel-IT for superior protection. These alloys are relatively cost-effective and display high ductility, strength, and low density at elevated temperatures.

However, the surface studies of the material play a crucial role in the understanding of surface properties, such as interactions, adsorption, oxidation-reduction, improved corrosion resistance, as well as magnetic moment. Very little information about Fe-Al surface studies is available. Hence, the need to investigate the phase stability and surface interaction, oxidation and hydration behaviour of Fe-Al alloys using computational techniques and codes, surface stability, the interaction of oxygen and water on the FeAl surface, adsorption energy of Fe-Al surfaces through ternary alloying with Pt, Pd, Ru, Ag and Ir.

I have published a number of papers with regard to this topic that helps in giving back to the economy and society. For example:

• Intermetallic studies on the mechanical and dynamical properties of Fe1-xYxAl (Y = Pt and Ru) Alloys. Link
• Thermodynamic stability of doped FeAl-X (X = Pd, Ag, Pt and Ru) systems. Link

Why is your research/work important?

Under oxidizing conditions, aluminide coatings offer a protective oxide scale. By selective oxidation of aluminium, Fe-Al intermetallic create stable aluminium oxide (α-Al₂O₃) on their surfaces, which contributes positively to oxidation and corrosion behaviours at high temperatures. High-temperature oxidation is an extremely damaging degrading mechanism for metallic surfaces, and if the metallic material does not create a protective oxide layer on its surface, it loses far too much base mass at high temperatures.

Austenitic stainless steel is the most often used stainless steel and is progressively being used in coal-fired boilers, heat pipes, steam turbines, and other applications. The most effective method for increasing stainless steel corrosion resistance is to put a protective coating on the material’s surface. Thus, aluminide coatings have remarkably become the most applied method in protective coatings for Al₂O₃ and possess excellent high-temperature corrosion resistance.

Metal-based multimetallics have attracted great attention for their multifunctional and synergistic effects, which offer numerous applications. Combined experimental and theoretical studies have enabled the formulation of various designs and performances by controlling size, composition, morphology and crystal structure at micro and meso scale. The prediction of new stable phases is one way of keeping up with the rapid change in climate, temperatures, moisture and humidity rate coming closer to sea level affecting housing infrastructures located thereof

There is still a long way to go to truly achieve equity and a sense of belonging for women, be it within the research community or society in general. How do you envision yourself contributing to this space?

I am a member of Women in Physics in South Africa and we host lunches every year in our respective universities to involve Grade 12 learners and undergraduate female students to help raise awareness for young women scientists. This is to inspire young females to pursue careers in Physics.

I am also part of Science Expo: Nka’Thutu Edu Propeller, which has created a program for learners in various schools registered in science streams. It encourages them to bring innovative STEM ideas, by identifying existing problems within the community and creating prototypes that will be turned into business cases.

What advice do you have for girls who are interested in STEM-related careers?

Science is the new booming field with the 4IR, technology-leading AI. This is an opportunity to maximise smart young female minds who are ready to lead. The grace to lead is not gender-based but intellectual-based.

Let everyone be a support system which you would have already established within yourself. Wanting to be unique, doing the uncommon will provoke a lot of opposition and much resistance, thus you must be ready to go beyond the literal discouraging voices. Establish a firm foundation within!

It is good to have mentors and seek advice but there’s also a thin line between good and bad intentions – it takes one word to derail great potential. Be ready to learn and makes changes were necessary for rigidity is a killer of progress and growth.

This work is licenced under an Attribution-NonCommercial-NoDerivs 3.0 South Africa (CC BY-NC-ND 3.0 ZA) license. Please view the terms for republishing here.