Friction and wear behavior of several hard materials

Sliding friction, abrasion and erosion tests were performed on several materials: cemented carbides, partially stabilized zirconia (Mg–PSZ), electroless Ni–P coatings and SAE 4140 steel as reference material. Sliding friction test was carried out in a pin-on-disk system. A micro-abrasion test was performed using the ball cratering methods. The erosion test consisted an air stream carrying abrasive particles of SiC, impinging flat samples. Sizes of wear scars were determined by optical microscopy and laser profilometry. Scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) were employed to observe morphological and chemical features of worn surfaces. The sliding pin-on-disk results of Ni–P coating showed smooth variation of the friction coefficient (mean values of 0.16–0.21), as well as the lowest wear rate compare with the other evaluate materials. Experimental results of the micro-abrasion test showed linear behavior between wear volume and sliding distance for all the evaluate materials. Cemented carbides showed the lowest wear rates followed by SAE 4140 steel, Mg–PSZ and Ni–P coating, respectively. Erosion test values ranked evaluated materials from lower to higher eroded volume as follows: SAE 4140 Steel, Ni–P coating, cemented carbides and Mg–PSZ ceramic.