Iron-based friction materials fabricated by in situ carbothermic reactions and vacuum sintering with Cr addition

Abstract

In this study, we fabricated iron-based friction materials directly by in situ selective carbothermic reaction and vacuum sintering from vanadium-bearing titanomagnetite concentrate and evaluated the effects of Cr on the microstructure, properties, and tribological behavior. The results reveal that Cr dissolves in the Fe matrix and contributes to the formation and refinement of pearlite, thereby improving the sintering densification and properties of the material. After adding moderate Cr, the microstructure becomes denser and more homogeneous, with improved sintering densification, hardness, and tribological properties. The dominant wear mechanism changes from severe abrasive and oxidative wear to mild abrasive and oxidative wear, indicating a decreasing wear degree. However, for Cr content exceeding 2 wt%, the sintering densification and properties slightly deteriorate. In particular, the material with 2 wt% Cr exhibits the optimal overall properties, with a much lower friction coefficient and wear rate than the sample without Cr. This work provides practical guidelines for further research on the properties improvement of the friction material.