Mild Wear Transition by Supply of Powder on Sliding Surface

当金属相互滑动时，观察到从严重的磨合磨损到轻微的稳定磨损的转变。在轻微磨损中，金属表面被一层保护性的氧化层覆盖，以防止金属间的接触，从而导致低磨损率。在本研究中，通过销盘磨损试验方法研究了添加氧化铁或铁颗粒对摩擦钢表面的影响。特别研究了供给量对严重磨合向滑动距离稳定磨损转变的影响，发现直径在0.5μm及以下的氧化铁微粒的供给加速了磨损由严重磨合向轻微磨损的转变。在这些磨损试验中，圆盘的磨损表面变色为红色，这表明摩擦表面形成了致密的氧化层。添加较细的磨粒后，严重-轻微磨损转变的滑动距离变小，这表明细小的磨粒容易在磨损表面形成致密层。另一方面，使用1μm的氧化物颗粒，没有观察到严重到轻微的磨损转变，产生了类似于不提供颗粒的试验中观察到的磨损曲线。本工作首次显示了氧化物颗粒的临界尺寸，它被认为是导致轻微磨损的表面形成保护性致密氧化物层的原因；直径在0.5到1.0μm之间。

When metals slide against each other, a transition from severe running-in wear to mild steady wear is observed. In mild wear, a metal surface is covered with a protective oxide layer that prevents intermetallic contact, resulting in a low wear rate.In this research, the effects of supplying iron-oxide or iron particles on rubbing steel surfaces were investigated by a pin-on-disc wear test method. Particularly, the influence of the size of supplied Fe_2O_3 oxide particles on the transition from severe running-in to mild steady wear with sliding distance was studied.It was found that the supply of fine oxide particles with diameters of 0.5 μm and less accelerated the severe-mild wear transition. In these wear tests, the worn surfaces of the disc were discolored to red, suggesting that compact oxide layers were formed on the rubbing surfaces. The sliding distance of the severe-mild wear transition was reduced when finer particles were supplied, suggesting that fine particles easily form compacted layers on the wear surface. On the other hand, employing oxide particles of 1 μm, no severe-mild wear transition was observed, producing a wear curve similar to that observed in the test where no particles were supplied. The present work is the first to show the critical size of oxide particles, which are considered to be responsible for the formation of protective compact oxide layers on the surface for mild wear; between 0.5 and 1.0 μm in diameter.