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

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 Fe_xO_y. 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.