Mechanical and tribological evaluation of CrSiCN, CrBCN and CrSiBCN coatings

To pinpoint effect of Si-B duplex doping compared to Si and B simplex doping, tribological properties of CrSiCN, CrBCN and CrSiBCN coatings were compared. It was found that CrSiCN coating was still intact after tribotest due to protection of iron oxides from GCr15 counterpart. In contrast, CrBCN coating presented the highest wear rate (4.9 x 10(-6 )mm(3)/Nm) while CrSiBCN coating showed a medium wear rate (2.3 x 10(-6 )mm(3)/Nm). For the same reason, CrSiCN/GCr15 tribopair presented the lowest friction coefficient (mu(m) = 1.07) because of low shear strength of iron oxides. CrSiBCN/GCr15 and CrBCN/GCr15 tribopairs presented a higher friction coefficient (mu(m) = 1.17 and mu(m) = 1.43). The results indicated that Si-B duplex doping was superior to B simplex doping but inferior to Si simplex doping for improving tribological properties.