Master’s thesis for PerforMat project - What was it like?


At the end of their studies every student faces the final climb, writing a Master’s thesis. There are a lot of possibilities to complete the thesis. The most traditional way is to conduct a commissioned development or research project for industry, but the university also offers research projects and topics. When I was going through all the possibilities, I came across an interesting job announcement on the university’s website about research assistant for Tribology and Machine parts research group.

My master’s thesis was part of the PerforMat-project, whose aim is to study and provide new information about advanced materials under demanding conditions in four different cases. My thesis was related to the case 1 where combination of fretting loading and hardmetal coatings was studied to get insight of the related phenomena and possibilities to mitigate fretting damage. Fretting, together with other damage mechanisms, is a serious problem in mechanical applications causing a notable decrease in service life and increase in operating costs and used resources.  Fretting is a problem found especially in various mechanical fittings, where the contact surfaces under normal load are in a small-amplitude reciprocating movement relative to each other creating slip between the surfaces, resulting in wear damage and fatigue cracks.

Inventing and optimizing new materials and solutions is important for more sustainable way of living as well as for reducing the use of limited natural resources and emissions. Due to the unsolved problems, a great need for the development of mitigation methods for fretting in various applications has been identified. Thermally sprayed hardmetal coatings combine high hardness with toughness, making them an interesting research topic under demanding loading conditions. In my thesis I studied fretting behaviour of HVOF and HVAF thermal sprayed WC-10Co-4Cr hardmetal coatings which were in contact with quenched and tempered steel. The study revealed clear differences in the behaviour of coating-steel contacts compared to traditional steel-steel contact. However, it became also clear that more work is needed before final conclusions can be drawn on the fretting resistance of the coatings, especially in terms of fatigue.

It was rewarding to get involved in an interesting project where my own work mattered. The given topic was versatile, as it combined fretting as a phenomenon, thermally sprayed coatings and their performance with steel, as well as the interaction of all of these. It was motivating to be able to work with a significant research question, although in some places this also caused some pressure and stress, but in the end, I would say it was still a rewarding and educational experience. For those who are starting the Master’s thesis project and the choice of topic is still in progress, I would say that if it is possible, choose a topic that really interests you. Writing a thesis is a big project and it is easier to maintain motivation when working on a topic that is interesting to you, even in difficult moments. As with all projects, there may be challenges along the way, which are also important lessons about project work.

During my thesis project, I learned a lot about the theory itself, but also gathered a lot of experience about experimental work and working with research project in practice. Right from the beginning, I got a lot of help and support from the supervisors and other members of the work and project community, which I think is one of the most important things in addition to regular feedback. Writing a thesis can sometimes be a rather lonely project, but regular support helps keep you sane. When working at a university, you have the huge opportunity to draw knowledge from a multidisciplinary scientific community, and it’s really worth taking advantage of it. If you are interested in the career of a researcher or postgraduate studies at the university, writing the Master’s thesis on a research project is a worthwhile choice. Moreover, it can open opportunities for work tasks that you did not imagine before, as it happened to me.

Master’s thesis is a learning process that enables deepening the theory and practice of the studied field, critical thinking, but also growing to tolerate uncertainty and imperfection. To quote Socrates “I know that I know nothing.”, and it is fine.

Vilma Haaja: Fretting behaviour of thermal sprayed hardmetal coatings against quenched and tempered steel, Tampere University 2022,

Text: Vilma Haaja, Tampere University
Photos: Anni Heikinheimo and Vilma Haaja, Tampere University

An example of development of fretting scar on coated surface
An example of development of fretting scar on coated surface (1000, 10 000, 100 000 and 1,3 e6 loading cycles from left to right). The scale bar has a line spacing of 1 mm.
Strereo microscope study
Vilma Haaja characterized the fretting samples using several methods.