No abstract

No abstract

The production of vanadium and niobium carbides (VC and NbC) layers on AISI 8620, 8640, and 52100 steels may increase hardness and wear resistance of substrates. Thermochemical treatments were performed at 1000 °C for 2 and 4 h. The characterization of the treated samples was carried out by means of Knoop microhardness tests, “calotest” type microadhesive wear test, layer adhesion test according to VDI 3198 standard, and X-ray diffraction. Compact and uniform layers of VC and NbC were obtained in all treatments, with hardness up to 2500 HK and microadhesive wear resistance far superior to that of the substrates, indicating the great efficiency of these treatments for tribological applications.

The following correction should be noted to this article: In the introduction, ''In order to increase steels hardenability, additions of boron between 0.0003 up to 0.003 wt.% improve fracture susceptibility and distortions during cooling'' should read ''To increase the hardenability of steels, additions of boron between 0.0003 and 0.003 wt.% decrease fracture susceptibility and distortions during cooling.''

In this work, boriding and Thermo-reactive Deposition (TRD) treatments for the production of boride and both vanadium and niobium carbide layers were performed on the substrates of AISI 15B30 steel to evaluate properties such as hardness, adhesive wear resistance, surface adhesion and chemical compounds present in the layers. For this purpose, layers were characterized by optical microscope, Knoop microhardness, microadhesive wear test, Rockwell C indentation adhesion according to VDI 3198 and X-ray diffraction. The results showed layers with high hardness (1400 - 2500 HK), greater microadhesive wear resistance (up to 15 times higher) when compared to the substrate and excellent delamination resistance.