Wear properties of Fe-Fe 3 C nanophase white iron obtained by mechanosynthesis and hot isostatic pressing

Dry sliding wear tests were carried out on an Fe-Fe₃C nanophase white iron, of composition 85Fe₃C-15Fe (vol.-%), produced by mechanosynthesis of powders and compaction. The tests were carried out using a fiat on cylinder tribometer, with the specimens sliding against a ceramic Al₂O₃-TiO₂ countermaterial under applied loads of 5, 10, 20, and 30 N and sliding speeds of 0.3, 1.2, and 1.8 m S^−l for sliding distances up to 10 km. During the tests the coefficient of dynamic friction and total wear were recorded by means of a loading cell and a linear variable displacement transducer respectively. The depth of the wear tracks was recorded using a stylus profilometer and the worn surface was investigated by scanning electron microscopy (SEM). X-ray diffraction analysis and SEM observations were performed on the collected debris and the damage to the countermaterial was evaluated. For comparison, the same tests and analyses were carried out on a type T high speed steel and on a WC-TiC-Co composite. The Fe-Fe₃C nanophase white iron underwent mild sliding wear up to F = 10 N; the type T high speed steel showed abrasive wear and the WC-TiC-Co composite showed both adhesive (low loads and sliding speeds) and abrasive (high loads and sliding speeds) wear. From the observation of the maximum depth of the wear tracks measured on the tested materials it can be noted that, at all speeds, the wear resistance of the nanophase white iron against the Al₂O₃-TiO₂ ceramic counterface up to F = 20 N is comparable to that observedfor the T high speed steel tested in the same conditions.