in the Chemical Engineering degree programme
How is the coating applied to the workpiece? Under which conditions do we achieve the desired optical and technological properties of the coating layer? How can we design our methods and processes so as to minimise the negative effects on the environment and decrease our operating costs at the same time?
These are questions which are answered in the Application Technology Laboratory through the practical utilisation of different application methods. We get to know the most important methods of paint application and obtain a first impression of how we can decisively improve the quality of the paint layer by optimising the application parameters.
An important aspect here is the correct practical handling of the various measurement methods to assess the optical and technical properties of the paint layer. This includes hue, brilliance and roughness as well as hardness, scratch resistance or elasticity.
Application techniques such as dip and spray coating or electrostatic power coating are considered. Manual systems as well as automated equipment with robot support are used here. Some of the laboratory work also involves looking at the drying process.
How can the corrosion resistance of metals or the effectiveness of corrosion-protection measures be assessed in practice? How do you select effective corrosion-protection measures? On the “Corrosion protection” practical laboratory course, participants learn the most important experimental methods and evaluation procedures to answer these questions, e. g.
Accelerated weathering tests such as salt spraying, condensed water test and cyclic testing methods
Galvanostatic/potentiostatic measurement of current-voltage curves
Scanning Kelvin probe
and use them to assess the following aspects:
Measurement of corrosion potential and corrosion speed
Assessment of the passivity of metals
Resistance against pitting corrosion
Effectiveness and mechanisms of corrosion-protection inhibitors
Investigation of the structure and effectiveness of conversion layers
Investigation of the corrosion-protection effect of coatings
Investigation of the failure of corrosion-protection coatings as a result of blistering, cathodic delamination and filiform (underfilm or filametary) corrosion
Comparative assessment of corrosion-protection coatings
Ascertaining why damage has occurred
On the “Building Protection” practical laboratory course, participants carry out model experiments to understand building material degradation on the one hand, e. g.
Morphology and chemical composition of building materials
Water transport in building materials
Water vapour diffusion
Salinity and impact of hygroscopic impurities on the water balance
Strength profile and moisture distribution
and also perform investigations to assess building protection measures, such as
Influence of coatings, hydrophobisation and other surface treatments on water and water vapour permeability
Destructive and non-destructive measurement of the moisture content of building materials
Assessment of the salinity of building materials
Reinforced concrete: Assessment of carbonation depth, corrosion of concrete-reinforcing steel (also non-destructively) and surface hardness
Non-destructive acquisition of strength profiles and assessment of stone consolidation measures
Assessment and selection of coatings in constructional steelwork
Assessment and selection of coatings in building preservation
The Design component offers a foundation course on the theory of colours and shapes as a4-hour compulsory lecture. It also offers compulsory electives and main courses on colour design as a 2-hour lecture; Creative Techniques as a 4-hour practical - workshop block; product design/colour as a full-day seminar of 8 SWS (theory and practice); technical and freehand drawing as a 2-hour seminar; and heritage protection as a 4-hour seminar.
Taking the teachings of the Bauhaus movement as their basis, the first lectures on the theory of colours and shapes discuss topics such as the theory of shapes according to Kerner Duroy, Johannes Itten and Wassily Kandinsky. Particular emphasis is placed on the chapter about the theory of colour. The main focus is on the theories of Goethe, Itten and other Bauhaus instructors.
In the lectures on colour design, issues of current colour design as well as product and object design, advertising and typography are addressed. Key elements are topics such as colour and its symbolism, its effect on people’s well-being, colour and health, as well as colour in printing and media techniques.
Creative techniques offers a workplace to practise and experiment with “colour as a creative means of expression” in the spirit of the Bauhaus teachings. The field of work is defined as the interface between “free and applied art”. According to Walter Gropius, art cannot be taught or learned, but good craftsmanship can. In free exercises on the topic of point, line and plane, a large variety of tools are used to work in black-and-white or colour.
The topics of applied colour design - architectural design and object design - are discussed in the Product design/colour course. Students practise how to critically handle colours and colour valences. Some parts of object design (e. g. typography/typeface) are undertaken on the practical level; possible visits to exhibitions, with a special emphasis on the topic of colour, complete the seminar.
Technical and free drawing is offered so students can learn how to read machine drawings. The focus here is on investigating the relationship between the 2 and 3-dimensional representation of simple objects or mechanical engineering parts. The course covers multi-view projection, and also includes the different parallel perspective representations as well as the (one-point) perspective drawing of objects with various vanishing points.
Students are set tasks of greater or lesser complexity, which they have to solve on their own in order to achieve a goal. i.e. they learn to develop paint formulations. The paints are then produced with different types of dispersing apparatus (Fig. 1, left).
The paints thus obtained are applied to appropriate surfaces (Fig. 2, centre) and dried or cured.
After testing the coatings, the students learn, for example, that the gloss and flexibility of the coatings decrease significantly with increasing pigmentation. They thus learn how the coating properties depend on the constituents of the paints (formulation/ingredients). In another case, they observe that pigments separate (Fig. 3, right); this damage pattern can be removed by adding a suitable silicone additive. The students thus become familiar with the effects of paint additives.
In the surface and nano-chemistry laboratory the focus here is on the characterization and chemical modification of surfaces and nano structures. The objective of the laboratory courses is to show students the correlations between the chemistry, structure and function of surfaces. This is illustrated by way of an example:
The silanisation of glass surfaces involves the application of a molecular film of alkoxysilyl groups to the surface. The quality of the films obtained can be controlled via the reaction parameters. This is verified by contact angle measurement of water. When the surface is structured, too, the wetting angle can be increased compared to the smooth surface. In this way we optain unwettable superhydrophobic surfaces (see fig. 1).
Further experiments deal with thiolization, nanopowder syntheses, sol-gel coatings, photocatalytic boundary layers, electrochemical double layers.
The following experimental techniques are used: Dip coating, screen printing, hydrothermal synthesis, UV-Vis spectrometry, zeta potential measurements, X-ray diffraction (see fig. 2), contact angle measurements (see fig. 3).
Research activitiesin the surface and nano-chemistry laboratory include
sorption equilibria of ions and polymers
electrokinetic powder characterisation (see fig. 4)
characterization of electrode materials of electrochemical energy storages
This laboratory teaches the students about polymer materials from their chemical composition and materials testing through to the production and post-processing of finished parts. The practical work focuses on getting to know the different material, processing technology and external factors which affect the material properties. Other specialisations are plastics processing and coating. Students have the opportunity to pretreat plastic parts themselves, to paint them and test the polymer-paint bond.
The laboratory on organic binding agents and pigments teaches students how to produce different binding agents and pigments themselves and to test them for specific criteria. Special emphasis is placed on the production of environmentally friendly binding agents. The binding agents and pigments produced undergo a physical characterisation and are subjected to application-related tests. The drying/hardening characteristics of binders and the tinctorial strength, for example, of pigments are tested.
In the Materials Testing Coatings Laboratory, students learn about fundamental tests in coating technology. This is done using simple self-produced and commercially available paints, printing inks and other coating materials and coatings.
Investigations of coating technology parameters which determine the process capability of paints not only form part of the laboratory experiments, but are also worked on in the form of exercises in the seminar.
The programme includes for example mechanical engineering tests such as layer thickness measurement, hardness, elasticity, flexibility, scratch and abrasion resistance.
Colour and gloss - the appearance of coatings is assessed visually and by means of methods such as gloss measurement with reflectometers, haze meters, goniophotometers and colour metrics.
Rheometry plays an important role in the laboratory and can be performed on three rheometers (two with gas bearings)
on paints and other coating substances
as used in paint development and quality control
The resistance of paints and printing inks against weathering and against chemicals, environmental chemicals, foodstuffs etc. is investigated using conventional methods (left microscopic image of the damage to a coating layer caused by the effect of a solvent droplet)
In the Inorganic Chemistry Laboratory, students learn to undertake chemical work in the laboratory, carry out experiments according to predefined tasks and record their work.
They perform experiments independently on the topics of titration (acid, precipitation, redox, complexometry), potentiometry, electrogravimetry, solubility product, photometry, AAS, qualitative analysis of cations and anions, production of preparations.
The practical work aims to familiarise students with various important analytical methods in practice, while at the same time consolidating their theoretical knowledge of important analytical techniques.
The actual content is subject to continual change to meet the requirements of those working with the methods in practice. Apart from fundamental experiments on chromatography and spectroscopy, modern methods such as the analysis of formaldehyde by means of HPLC or DIN methods and cation determination by means of polarography are taught.
In the Organic Chemistry Laboratory, the students receive simple instructions and thus practise how to properly assemble glass apparatus, recognise hazardous materials and learn how to handle them properly. The experiments are chosen such that the students gain insights into the following methods as they perform them: dosing of liquids and solids, heating and cooling, mixing and shaking, drying and purification of liquids and solids.
The substances presented are identified to determine the most important physical properties using simple methods such as the determination of the melting point, refractometry, thin-layer chromatography and polarimetry.