The functional configuration of surfaces

Tribology and surface design

Component surfaces can often be damaged by the stresses of the manufacturing process as well as in normal use. Yet the condition of the surfaces can determine the functionality of a technical system. Scientists at the Fraunhofer IWM have extensive know-how combined with methods and processes which assure that specific properties belonging to the surfaces of parts and components, such as a low coefficient of friction, provide a specific surface energy or a desired visual appearance.

Specific developments for clients and project partners usually begin with an investigation of the failure mechanisms related to the surfaces involved using modern testing stations or by creating entirely new analysis techniques in order to determine the surface characteristics. The application of special simulation methods is useful for interpreting the experimental observations and evaluating damage events, thus helping to reduce the time required for subsequent development of coatings and techniques. These involve high-performance coating technologies together with specific edge-layer modifications and new processing methods.

Experts at the Fraunhofer IWM examine a wide range of problems. An example is the manufacture of bearings, where typical objectives would be to obtain stable friction conditions as quickly as possible, to assure particular dry-running properties or to achieve the longest possible service life. In plant construction and mechanical engineering the Fraunhofer IWM deals with questions concerning corrosion mechanisms, efficiency improvements and the possibilities for material pairing. In optics manufacturing and injection molding, methods are developed for damage-free demolding, online temperature measurement for molding tools and surfaces for forming tools that can realize the component surface properties required. In addition to the classification of layers, the Fraunhofer IWM develops coating techniques designed to achieve specific layer properties such as surface topography and microstructure.


How to work with the Fraunhofer IWM

Surface functionalization


Characterization and control of wear, wetting behavior, visual appearance, gloss level and haptics of component surfaces

 

Characterization of surface contours and topography:

Atomic force microscope AFM
Scanning electron microscope REM
Profilometer and roughness measurement devices
Optical microscope
Confocal laser scanning microscope CLSM
White light inferometer WLI
Inferometer with phase modifier

Determination of surface conductivity and wavelength-dependent measurement of reflection, transmission and color:

High-resistance ohmmeter
4-point resistance measurement
Glass fiber spectrometer
Wavefront measurement facility

Coating and plasma treatment of surfaces by various methods:

Reactive magnetron sputtering (HF, DC, pulsed DC)
Ion radiation techniques
Electron beam evaporator
PECVD systems
Plasma etchers

to top

Chemical and mechanical properties
 

Evaluation, modification and optimization of corrosion stability, adhesion, catalysis, material compatibility and diffusivity of component surfaces

 

Determining the composition of the chemical structure of surfaces and layers, spatially resolved and depth-dependent, plus phase analyses:

Confocal Raman microscope
FTIR spectrometer
ECP-OES optical emissions spectroscope
Glimmer discharge spectrometer GDOES
Energy-dispersive x-ray spectroscope EDX
X-ray photoemission spectroscope XPS
Quadrupole mass spectrometer

Surface energy and contact behavior measurement:

Test rigs for glass and plastics contact
Contact angle measurement device with temperature probe

Direct measurement of corrosion behavior:

Atlas cell test rig (cold-wall effect)
Elcometer 266 high-voltage holiday detector
Test rig for electrochemical noise
Electrolysis cell for hydrogen diffusion measurement
Test rig for corrosion in hot melted salts

Application-specific surface conditioning:

Coatings
Blasting processes (metals, ceramics)
Heat treatment processes

to top

Mechanical properties
 

Optimization of tribo pairs; determining of friction coefficient, wear resistance, dry-running behavior, lubricant stability and fretting behavior of components in use

 

Determination of tribological properties using application-specific tribo test rigs:

Piston-ring liner simulator with radionuclide technology RNT
Pin-on-disc tribometer with RN-T technology
Bearing and component test rig with RN-T
Pin-on-disc, rolling wear and ball bearing test rigs
Oscillating sliding abrasion test unit
Microtribometer
Tribocorrosion test rig
Hysitron TI 950 TriboIndenter
Tetra BASALT MUST, BASALT HOMAT surface testers
In house-developed UHV microtribometers and multiscale tribometers
Ice tribometer
Rheometer
Engine test rig

To determine the mechanical properties of edge layers and coatings, such as layer thickness, hardness, adhesion, inherent stresses and elastic modulus:

Layer thickness measurement (eddy current, magneto-inductive)
ScanningScratchTest SST
Rupture test
Nano indenter
Rockwell indentation, ball indentation
Scratch
Zygo interferometer for warp measurement
Ball impact test
Micromechanics test rig

to top

Surface coating and conditioning
 

Processes for development and application of application-specific coatings, in combination with suitable surface conditioning where appropriate:

Reactive magnetron sputtering (HF, DC, pulsed DC) with HF substrate biasing
Ion radiation techniques
Electron beam evaporator
PECVD systems
Plasma CVD coating systems CCP/ICP
Multi-chamber coating system for multiple-layer coatings and hybrid coatings
Plasma etching systems
Wet chemical coating systems (spin coating, knife coating, dip coating)
Ion etching unit for sample preparation and surface treatment
Ultra-precision turning, grinding and milling machine for diamond machining of forming tools
Shot peening systems for surface hardening and structuring

to top