Admissible stresses in thermal sprayed coatings

Friction materials of current railway brake discs have to support more and more frictional and thermomechanical stresses. It has been shown that some specified couple of materials, composed of a plasma sprayed disc coupled with sintered ceramic pads, leads to good behaviour in high speed train braking simulation. It's now to show coatings' reliability and reproductibility as well as limits of such solutions. To that objective, present work consists in testing coatings adhesion or cohesion. Numerical models have been developed to show that the coating's failure energy is representative of admissible stresses state in coatings. Some results are then discussed.