Dry Sliding Tribological Behavior of Columnar-Grained Fe2B Intermetallic Compound Under Different Loads

Abstract

The dry sliding tribological behavior of a columnar-grained Fe2B intermetallic compound under different normal loads was evaluated by scanning electron microscopy (SEM), XPS, and 3D laser scanning microscope. The results indicated that under a load of 12 N, after a 35 min break-in period, the dynamic friction coefficient decreased from 0.78 to about 0.6 and this low value was maintained until the end of test. When the normal load increased from 4 N to 20 N, both the average friction coefficient and wear rate values initially decreased and then increased. The lowest values of the average friction coefficient and wear rate were obtained under a load of 12 N. As the load increased from 4 N to 12 N, a complete film formed on worn surface. Nevertheless, when the load increased to 16 N, severe self-induced vibration occurred and a corrugated ribbon appeared on the surface. Furthermore, severe damage on the worn surface was caused by cycling vibration under the 20 N load. Under 4 N and 12 N, the main wear mechanism was abrasive wear, while under a load of 20 N, fracture wear and abrasive wear were the mian wear mechanisms. The friction products were composed of B2O3, H3BO3, SiO2, and FexOy. More specifically, Fe2O3 was generated under 4 N load, Fe2O3 and Fe3O4 were produced under 12 N load, and the mixture of FeO, Fe2O3, and Fe3O4 appeared under 20 N load.