Technical skill sheet

Surfaces and tribology

  • Centre of research : MINES ParisTech, centre de mise en forme des matriaux - CEMEF
  • Prestation : Characterization, tries, tests, checks, formulation - Research and Development

Contact Expert


Know-how


Surfaces and tribology :

Analysis of surface and interface phenomena in particular but not exclusively those concerning contact with products/tools in forming processes and assembly of material (friction, lubrication, wear, evolution of superficial composition or rugosity, adherence)

Physical-chemical composition of surfaces and contact mechanics, the team characterises material surfaces in terms of mechanical and chemical properties, from micro - to nanometer range. It develops modelling applications and digital simulations for rolling, in cooperation with the group CIM

Fields of research : - surface reactivity - adhesion / adherence / bonding - determination of advanced friction laws - models of abrasive wear - mechanical characterisation of coatings and thin films

Applications


Performances of forming procedures are often limited by problems linked to the contact between product and tools such as: adhesion, friction, wear. To improve production or to acquire the desired surface characteristics, often lubrication or surface coatings are used (hard on tools, soft on the product).

Our competences combines contact mechanics and its digital modelling as well as determination of elemental and molecular composition of surfaces and materials.

CEMEF research activities concern all types of material (metal, polymers, composites, glass...)

Equipment


Forming machine : - single screw extruder Kaufman diam. 40 mm, single screw Collins for rubber extrusion, double screw Clextral BC45 - controlled rolling train (20 m/s) - hydroforming machines for pipes, hydroforming machines for metal sheets or bulge test - deep drawing press (30t) - injection compactor DK (110t)

Instrumented prototype for blowing double-drawing of bottles : - rheocord Haake (internal mixer, single screw extruder - rolling trains/compactors : - vertical compactor "Psidix" - horizontal compressor

Development department and work shop : CAO/DAO 3D IDEAS MS11 - 3 towers, one with digital controls - 3 milling machines, 2 with digital controls - 1 mini milling robot to turn around sample bar - 1 grinder - various machines for cutting, folding, welding, grit blasting

Microscopy : - optical transmission microscope (with microtraction device, film micro-compression, static crystallisation, in shear and in elongation) - inversed metallographic optical microscope Olympus PMG3

Scanning electron microscope : - environmental (Philips XL30 ESEM LaB6), heating plate Oxford 1500C, automatic EBSD with digital camera and Peltier effect plate Philips - Jeol 35CF - transmission and scanning electron microscopes (CM12 TEM/STEM Philips) with heated object holder 600C

Spectrometers : - EDX (Oxford/Inca on MEB Philips XL30 ESEM), (Tracor/Noran on MEB Jeol 35CF) - XPS (Riber MAC2) - static SIMS at flight time [ToF-SIMS] (PHI TRIFT I)

Infrared (Fourier transformed, microscope) - X-ray: diffractometer (X'pert Pro), texture goniometer, Debye Scherrer chamber

Physical measurements : small angle light diffusion - moulding goniometer - rugosimeter 3D - image analyser (Visilog 6.3) - machine for measurements of thermal exchange coefficients - enthalpic differential analyser (DSC Perkin Elmer) - measurement system (deformations, displacement and thickness) by image correlation (ARAMIS system) - non-contact measurements, flow and deformation visualisation : - machine tools with observation windows (injection cast with transparent walls, pipes) - Doppler laser anemometer (Dantec) - flow birefringence - high speed camera (125 to 2500 images/s) - videometric extensometer - mechanical properties : - hardness, cold and hot, micro hardness, macro hardness - Instrn traction (+/-100kN, heating up to 1200C, LN2 cooling, videometric traction and compression control system) - hydraulic traction-compression Dartec (300mm/s, +/-300kN) - hydraulic high-speed traction-compression Zwick (0.5 to 20 m/s, +/-20kN, up to 250C and LN2 cooling) - electro-mechanical traction for important displacements Erichsen - torsion Adamel-Lhomargy (heating up to 1200C) - mini-torsion with joule effect heating and resistivity control - hammering machine, drop shaft - furnace for thermal processing, vacuum or under atmosphere (1200C)

Rheometry : - capillary rheometers (Rhoplasts(r)) - rotative rheometers (imposed deformation Rheometrics RMS 800, imposed constraints Stresstech Rheologica) - rheo-optical devices (optical and plane-plane light diffusion microscopes, plane cone, coaxial cylinders, four rolls. Tubes and casts transparent. Microtraction).

Tribology : - punching, plane drawing - rotative tribometers, plane-plane

Thermomechanical wear machine - machine for tool steel wear - friction coefficient measurements of metal-polymers.