Mn-Znフェライトのアブレシブ摩耗 (第2報)

Abstract

An investigation has been carried out to study the variation of wear rate of ferrites with variation of the carrier fluid (an olive oil and a kerosene), the sliding speed (0.05-1.0 m/s) and abrasive/carrier fluid ratio (5-50%). When the relatively high viscous olive oil is used, the wear rate decreases rapidly with increasing sliding speed. This seems to be due to increasing load carrying capacity of the oil. The wear rate obtained using the low viscous kerosene is no longer dependent upon the sliding speed. At low sliding speeds, the wear rate depends on the abrasive/fluid ratio, the ratio of 27% gives the maximum wear rate. At high sliding speeds, however, the wear rate is independent of the abrasive/fluid ratio. Surface roughness of worn surface in the olive oil depends on the sliding speed. The dependency is smaller than that of the wear rate. When the kerosene is used, the surface roughness is slightly dependent upon the sliding speed, and the abrasive/fluid ratio at any sliding speed. A discussion was made of the mechanism of abrasive friction. The friction force is the sum of two components, the contact rolling and scratching force of the abrasive FD and the viscous drag force FF. FD is generally proportional to the contact pressure and it is independent of the sliding speed. FF can approximately expressed as FF=ηA (VF/h). The thickness of oil film h estimated with this equation is slightly dependent upon the contact pressure, sliding speed and crystallographic plane of ferrite, respectively.