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Definition: Coating technology comprises processes for the targeted application of functional or protective layers onto material surfaces. The aim is to improve corrosion protection, wear resistance, and electrical or thermal properties. The layer can be metallic, ceramic, polymer-based or designed as a composite system.

Practical relevance: Industrial processes include physical and chemical vapour deposition (PVD, CVD), thermal spraying (DIN EN 657), electroplating, powder coating and painting technology. Layer thickness (µm), adhesion strength (DIN EN ISO 4624), porosity, roughness and corrosion resistance (DIN EN ISO 9227) are evaluated. Defective coating systems lead to filiform/under-film corrosion or delamination.

Decision-making perspectives:

• Technical decision-makers: selection of suitable coating systems depending on medium, temperature and tribological load.
• Purchasing/project management: specification of layer thicknesses, standard tests and acceptance criteria.
• Science: analysis of interfaces, diffusion zones and layer-growth mechanisms.
• Insurance/law: proof of standard-compliant execution and documentation in the event of corrosion damage.

Typical testing or verification methods: layer thickness measurement, cross-cut test, pull-off adhesion test, salt spray test, SEM/EDX analysis.

FAQ:

• How is the quality of a coating tested?
• By measuring layer thickness, adhesion strength and porosity, as well as through standardised corrosion and wear tests.

Definition: Component metallography is the metallographic examination of the microstructure directly on the component or on representatively extracted samples. It serves to assess heat-treatment conditions, weld seam qualities and damage-relevant microstructural changes. It is based on preparative sectioning techniques as well as light or electron microscopy analyses.

Practical relevance: Grain size (DIN EN ISO 643), phase distribution, precipitates, crack formation or decarburisation depths are evaluated. The method is central to failure analysis, in cases of suspected HTHA (High Temperature Hydrogen Attack) or for verifying material specifications. Replica techniques enable in-situ examinations without full disassembly.

Decision-making perspectives:

• Technical decision-makers: assessment of microstructural inhomogeneities, weld seam zones and remaining service life.
• Purchasing/project management: verification of specification-compliant heat treatment and manufacturing quality.
• Science: microstructure analysis, correlation of microstructure and mechanical properties.
• Insurance/law: documentation of the material condition to secure evidence in the event of damage.

Typical testing or verification methods: sample preparation, light microscopy, scanning electron microscopy (SEM), hardness testing, microstructure etching.

FAQ:

• Is component metallography possible non-destructively?
• Replica methods are minimally invasive; classic sectioning examinations require material extraction.

Definition: The compression test is a mechanical testing method for determining the behaviour of a material under axial compressive loading. A cylindrical or prismatic specimen is loaded between two compression platens up to a defined load or until failure. The method is standardised, among others, in DIN EN ISO 6892-1 (for metals, complementing the tensile test).

Practical relevance: The properties determined are compressive strength, modulus of elasticity and plastic compression behaviour. The compression test is particularly relevant for brittle materials such as cast iron, ceramics or concrete, where the compressive strength is considerably higher than the tensile strength. Influencing factors are specimen geometry, friction at the compression platens and testing speed.

Decision-making perspectives:

• Technical decision-makers: Design of compression-loaded components and assessment of failure mechanisms.
• Purchasing/project management: Specification of required minimum compressive strengths in material specifications.
• Science: Analysis of non-linear deformation mechanisms and material models.
• Insurance/law: Documented verification of mechanical properties in cases of structural failure.

Typical testing or verification methods: Universal testing machine with compression platens, strain measurement, evaluation of stress-strain curves.

FAQ:

• When is a compression test more appropriate than a tensile test?
• For brittle materials or components that are predominantly subjected to compression, the compression test provides more realistic characteristic values.

Definition: Contour measurement is a metrological method for capturing and evaluating profile shapes and geometry elements of a workpiece. In the process, actual contours are compared with nominal data. The aim is to assess form deviations, radii, angles or transitions.

Practical relevance: Contour measurements are particularly relevant for sealing faces, grooves, gear teeth or free-form surfaces. Tactile stylus instruments or optical measuring systems are used. The basis for evaluation is technical drawings or CAD models as well as GPS standards. Influencing factors are the stylus force, filter settings and measurement uncertainty.

Decision-making perspectives:

• Technical decision-makers: Ensuring function-relevant profile geometries and transition radii.
• Purchasing/project management: Defining clear contour and profile requirements in specifications.
• Science: Analysis of profile deviations and signal processing (filters according to ISO 16610).
• Insurance/law: Demonstrating geometric deviations in the case of functional or leak-tightness problems.

Typical testing or verification methods: Stylus profiling method, optical profilometry, CAD comparison measurement, evaluation with form and profile tolerances.

FAQ:

• How does contour measurement differ from roughness measurement?
• Contour measurement evaluates macrogeometric profile shapes, whereas roughness measurement analyses microscopic surface structures.

Definition: Corrosion engineering covers the holistic planning, assessment and optimisation of corrosion-relevant aspects in technical installations and products. It integrates material selection, protection concepts, operating parameters and inspection strategies. The aim is to sustainably ensure integrity and cost-effectiveness.

Practical relevance: The basis is knowledge of corrosion mechanisms, media conditions, temperature and pressure ranges as well as normative requirements (e.g. DIN EN ISO 8044, API 571). Measures include suitable material selection, coating systems, cathodic protection, water chemistry control and Risk-Based Inspection (RBI). A lack of systematic planning leads to increased maintenance costs and failure risks.

Decision-making perspectives:

• Technical decision-makers: Development of integrative corrosion protection strategies across the entire life cycle.
• Purchasing/project management: Definition of clear material and protection requirements in specifications.
• Science: Modelling of corrosion rates and assessment of new protection technologies.
• Insurance/law: Demonstration of systematic risk assessment and compliance with technical codes and standards.

Typical testing or verification methods: Corrosion testing, electrochemical analyses, wall thickness measurement (UT), RBI analyses, materials analytics.

FAQ:

• What distinguishes corrosion engineering from individual tests?
• It considers corrosion risks holistically and with a life-cycle orientation rather than as isolated individual tests.

Definition: Corrosion mechanisms describe the physico-chemical processes that lead to the degradation of a material through reaction with its environment. They are usually based on electrochemical redox reactions between metal, electrolyte and oxidising agent. The type and progression depend on the material, medium, temperature and mechanical loading.

Practical relevance: The most important mechanisms include uniform surface corrosion, pitting corrosion, crevice corrosion, galvanic corrosion, stress corrosion cracking (SCC) and hydrogen-induced cracking. Evaluation parameters are the corrosion rate (mm/year), potential differences, pH value and chloride content. Normative definitions can be found, among others, in DIN EN ISO 8044. Knowledge of the mechanism is a prerequisite for effective corrosion protection.

Decision-making perspectives:

• Technical decision-makers: Selection of suitable materials, coatings or protection systems.
• Purchasing/project management: Specification of corrosion-resistant materials and testing requirements.
• Science: Analysis of electrochemical processes and material-medium interactions.
• Insurance/law: Determining the cause of corrosion damage and assessing the duty of care.

Typical testing or verification methods: Electrochemical measurements, salt spray test, metallography, wall thickness measurement (UT).

FAQ:

• Why is identifying the corrosion mechanism important?
• Only by knowing the mechanism can suitable protection and prevention measures be defined.

Definition: Corrosion protection encompasses all technical measures to prevent or slow down corrosion of materials. It can be achieved through design, materials engineering, electrochemical means or coating systems. The aim is to extend service life and ensure operational safety.

Practical relevance: Measures include suitable material selection, coating systems in accordance with DIN EN ISO 12944, cathodic corrosion protection or adjustment of the water chemistry. Protection duration, coating thickness, adhesion strength and inspection intervals are assessed. The effectiveness depends strongly on environmental conditions such as humidity, chloride content and temperature.

Decision-making perspectives:

• Technical decision-makers: Selection of economically and technically suitable protection concepts.
• Purchasing/project management: Specification of protection classes, coating systems and testing requirements.
• Science: Investigation of passivation, diffusion processes and protection mechanisms.
• Insurance/law: Demonstration of appropriate protective measures in the event of corrosion damage.

Typical testing or verification methods: Salt spray test, coating thickness measurement, pull-off adhesion test, potential measurement in cathodic protection.

FAQ:

• Which standard governs coating systems in corrosion protection?
• DIN EN ISO 12944 describes the corrosion protection of steel structures by means of coating systems.

Definition: Corrosion testing is the experimental investigation of the resistance of a material or coating system to corrosive media. The aim is the quantitative or qualitative assessment of corrosion behaviour under defined conditions. Test methods are governed by standards, for example in DIN EN ISO 9227.

Practical relevance: Corrosion tests include salt spray tests, climatic tests, immersion tests or electrochemical measurements. The corrosion rate, mass loss, pitting corrosion or undercutting of coatings are assessed. The results serve material selection, qualification of coatings and service life estimation.

Decision-making perspectives:

• Technical decision-makers: Selection of suitable material or coating systems for defined media.
• Purchasing/project management: Definition of binding test requirements and acceptance criteria.
• Science: Investigation of corrosion kinetics and comparison of accelerated test methods with field exposure.
• Insurance/law: Demonstration of resistance or root cause determination in the event of corrosion damage.

Typical testing or verification methods: Salt spray test (DIN EN ISO 9227), condensation cyclic climate, electrochemical polarisation measurement, long-term exposure.

FAQ:

• Does the salt spray test replace real operating conditions?
• No, it is an accelerated comparative method and reflects real operating conditions only to a limited extent.