Antifriction characteristics of quasi-nano alumina reinforced with Zr-O-B compounds against cemented carbides

In this paper, Zr-O-B compounds that strengthened quasi-nano alumina composites were produced by hot pressing techniques. The mechanical properties of the composite as well as its wear behaviors, coupled with a cemented carbide ball in unlubricated conditions, were investigated systemically. SEM and EDX techniques were employed to observe the worn surfaces of the test specimens and antifriction mechanisms were simultaneously discussed. Analysis of the experimental data and observation on worn surfaces revealed that the improvement in the wear resistance of composites may be attributed mainly to the addition of Zr-O-B compounds in the alumina matrix. The mechanism responsible was explained as the formation of a lubricating film between the sliding couple, and the composition of this lubricating film was found to be ZrO₂ and B₂O₃. The generated lubricating film can decrease the friction coefficient of the composites, and prevents the wear rate from reaching the theoretical value.