Synthesis of Iron-Based Friction Material by in Situ Reactive Sintering from Vanadium-Bearing Titanomagnetite

Abstract

Based on the thermodynamic analyses, an iron-based friction material has been prepared directly from the vanadium-bearing titanomagnetite concentrates by means of a prereduction process and a final sintering process. Thermodynamically, ferrous oxides, titanium oxides, and vanadium oxides in the vanadium-bearing titanomagnetite concentrates can be converted to metal iron, titanium carbide, and vanadium carbide, respectively, by carbon at 1300°C in a vacuum of 10 Pa. During the process of prereduction, the percentage of ferrous oxides reduced to metal iron is about 96%, the percentage of FeTiO3 converted into TiC is about 75%, and the percentage of V2O5 converted into VC is about 94%. During the process of final sintering, the samples were sintered at 1000°C for 3 h. The density, compressive strength, and Brinell hardness of this iron-based friction material are 5.07 g · cm−3, 154.82 MPa, and 64 HBW, respectively. Its porosity ratio is about 18%. The stable coefficient of friction between this iron-based friction material and GCr15 is about 0.57 and the corresponding wear rate is 1.0145 × 10−7 cm3 · J−1. Consequently, the two-stage process presented in this paper can not only utilize the vanadium-bearing titanomagnetite concentrates effectively, but also find an alternative method to produce iron-based friction material economically.