An industrial process can only be controlled reliably if we know what is actually happening within it. The phase composition of steel, the ionisation of particles in a deposition chamber, gas concentrations in a plasma reactor or the level of molten metal are not quantities that can easily be observed with the naked eye.
These were precisely the quantities measured by the Sensors for the 21st Century project. Its results are not linked to a single type of sensor or one industrial sector. Their common principle is to replace estimates, feedback checks and trial-and-error adjustment with data that can be used in materials development, quality control and production management.
What Lies Inside Steel and on Its Surface
The phase composition of steel has a major effect on its hardness, resistance and service life. A team from the Faculty of Science at Palacký University Olomouc therefore developed a device that uses Mössbauer spectroscopy to determine the proportions of austenite, martensite, iron carbides and other phases non-destructively.
The component being measured does not need to be pre-treated or damaged, and the detection limit for individual phases is below 1%. The device can be used, for example, to inspect retained austenite in gears and pinions, analyse bearing rings, or optimise steel forming and heat treatment. One device has already been installed at Třinecké železárny, and the technology has also been tested in cooperation with COMTES FHT, Mubea and Sigma Group.
The second detector developed focuses on changes that occur only in an exceptionally thin surface layer and may remain hidden when the entire volume of the material is analysed. By detecting conversion electrons, it can determine the phase composition of the surface of steel components to a depth of approximately 500 nanometres. It distinguishes between individual phases and corrosion products and can support the study of oxidation, corrosion, wear and the effects of different machining methods.
Measuring Coating Processes Directly during Production
Hard protective coatings applied to industrial tools do not necessarily have the same properties throughout a deposition chamber. The coating growth rate and the proportion of ionised particles vary depending on the position of the coated component, source power, working-gas pressure, target wear and the material used.
Masaryk University and SHM therefore developed a sensor using two quartz crystal microbalances. The first measures the total particle flux, while the second measures only neutral atoms. The difference makes it possible to determine the proportion of the ionised component and describe how the deposition process changes in different parts of the chamber.
Measurements were carried out in SHM’s industrial DRAK system and were used to optimise AlTiN- and AlCrN-based coatings, as well as a coating combining magnetron sputtering with arc evaporation. The result is not just the sensor itself, but also a procedure for measuring and setting up a specific industrial system based on data instead of laboriously searching for suitable parameters by trial and error.
A Plasma Platform for New Functional Materials
Another result was developed at the Institute of Physics of the Czech Academy of Sciences. The plasma technology platform makes it possible to prepare semiconductor layers and multilayers using various reactive sputtering methods and to monitor how the deposition method affects their structure and functional properties.
Using the platform, the researchers prepared and compared, for example, tin oxide layers sensitive to hydrogen, photoactive TiO₂ layers for hybrid UV, X-ray and gamma-ray detectors, and ZnO/SnO₂:F systems for photoelectrochemical applications. The results showed that the sensitivity, electrical properties and response time of the resulting material can be deliberately influenced by selecting a suitable plasma technology and process parameters.
A New Principle for Hydrogen Detection
As hydrogen technologies expand, so does the need for their safe operation. Hydrogen is highly flammable, invisible and odourless, so leaks must be monitored by reliable sensors.
Researchers from the Institute of Thermomechanics of the Czech Academy of Sciences created a functional sample of a chemiresistive sensor with a nanostructured Pt/WOx layer. It detects the presence of hydrogen through a change in electrical resistance. During testing, it responded to concentrations from 0.1% by volume, while the sensitive layer operated at 50 °C.
The way the sensitive material is produced is also noteworthy. Nanoparticles are generated directly from pure metals using electrical discharges and deposited onto the supporting layer without solvents or binders. The team also created a test platform for setting the hydrogen concentration and monitoring the sensor response. The result is not yet a finished detector ready for industrial deployment, but a validated principle that can support further development of response speed, selectivity and long-term stability.
Testing Sensors in Different Parts of a Plasma Reactor
A separate project result addresses the broader question of how to test sensors under conditions corresponding to a real plasma process. Temperature, flow and the composition of the gas mixture vary significantly in different parts of a reactor, whereas conventional laboratory equipment generally allows measurements at only one location.
The Institute of Plasma Physics of the Czech Academy of Sciences and the Institute of Physics of the Czech Academy of Sciences therefore developed the Multichamber, a multi-chamber microwave plasma system. Temperature and gas sensors can be installed simultaneously in its four measurement chambers, making it possible to compare their behaviour at different distances from the plasma discharge.
The numerical model also predicts gas flow, the concentrations of individual components of the gas mixture and the temperature distribution in different parts of the reactor. The system’s functionality was verified during the plasma decomposition of methane, which produced hydrogen and carbon nanoparticles. The equipment can be used to develop, calibrate and test sensors, as well as to design future plasma-chemical technologies.
When Measured Data Take Over Process Control
The system for plasma melting of metals, developed by Advanced Metal Powders and the Technical University of Liberec, came closest to direct automated production control. In this process, pre-alloyed rods are melted by a plasma arc and the molten metal solidifies in a water-cooled mould into an ingot for further processing.
However, the intense plasma radiation overexposes a conventional camera image and makes it difficult to monitor the level of the melt. The system developed therefore combines a cooled camera, spectral optical filters and an artificial-intelligence model. In real time, the AI recognises the melt level and sends it to the control system, which automatically adjusts the speed at which the material is drawn from the mould according to the measured changes.
The technology was verified in 14 melts, including the processing of rods manufactured using HPAM technology. Under standard operating conditions, the control behaved in a stable and predictable manner. Before it can be deployed in fully unattended operation, testing of critical situations will still need to be completed and backup safety mechanisms added.
From Individual Measurements to Better-Controlled Production
The project results vary in their level of readiness. Some devices have already been verified under industrial conditions or installed directly at companies, while others are functional samples and experimental platforms for further development.
Together, however, they show how broad a role sensor technology can play in modern industry. It can reveal changes inside materials and on their surfaces, monitor production-process parameters, test new sensors in demanding environments and use the data obtained for automatic control. It is precisely the connection between research institutions and industrial partners that helps turn these possibilities from laboratory experiments into concrete applications.
About the Project
The Sensors for the 21st Century project was part of the National Centre of Competence for Materials, Advanced Technologies, Coatings and Their Applications (NCK MATCA), supported by the Technology Agency of the Czech Republic.
The NCK for MATCA is supported by the