Low load multiple scratch tests of ceramics and hard metals

Dry Reciprocating Sliding Friction and Wear Response of WC–Ni Cemented Carbides

“…9b, e, and the presence of cobalt in the EDX spectrum of the WC-Ni grade-A, Fig. 9c, together with the decreasing roughness of the wear track bottom (Table 2), presume the possible formation of an ultra-fine tribolayer [37,38] containing oxides as a result of the compaction of wear debris and/or the smearing and oxidation of binder phase. The expulsion of binder phase from between the tungsten carbide grains as described by [36] is thought to constitute the initial stages of wear and to result in carbide removal and/or carbide fracture.…”

On the Abrasion of Ultrafine WC–Co Hardmetals by Small SiC Abrasive

“…Formation of the tribomechanical layer for all the coarse and medium-coarse grades abraded by coarse abrasive was noticed in the present research. In literature, formation of a tribolayer at a worn surface of WC-Co hardmetals has been reported for grinding [9], dry sliding [10] and multiple scratch tests [11]. Nevertheless, formation of the tribomechanical layer at dry abrasion has not been usually reported.…”

Wear Simulation of Polymer Using Multiscratch Test Procedure

“…In the case of purely elastic sliding contact, this last friction coefficient, which is the plough effect, can be neglected and the apparent friction coefficient l app can be assimilated in first approximation to the local friction coefficient l ad , which represents the interfacial shear stress [13]. By comparison with similar studies using multiple scratch test procedure to characterize hard metals or ceramic coatings [7][8][9], we are able to observe, in the case of amorphous transparent polymers, the true contact geometry between the moving tip and the deformed surface. During each pass, three optical micrographs were recorded (i) at the beginning of the scratch (zone I), (ii) in the middle of the track (zone II) and then (iii) at the end of the scratch pass (zone III), as shown in Figs.…”

“…Such damages are mainly responsible of wear. Although single scratch events at constant or progressive load test procedure provide interesting information, performing multiple repeated scratches along the same scratch path provides much more comprehensive information about the build-up of irreversible phenomenon (yielding rate and plastic pile formation) and damage (amounts of brittle failure) [7]. This specific experimental procedure, carrying out on a given sample with a different number of repeats along the same track has been previously used to simulate low stress abrasion of ceramic and hard metals [7], to reproduce the wear damage mechanisms that take place in thermally sprayed coating [8] and also to characterize the adhesion of a TiN coating a steel and titanium alloy substrates [9].…”