Preparation Technology Of Bi-continuous TiC/Fe Composites

In this paper, bi-continuous TiC/Fe composites were prepared with iron as matrix and TiC as enhancement phase with the working condition of high temperature, high speed and wear resistance. This bi-continuous structure forms a strong mutual restraint between ceramic and metal matrix, and supporting each other in the work is conducive to give full play to their respective performance advantages, which has a wide application prospect.Three-dimensional network structure TiC porous ceramics were prepared by organic precursor impregnation method using polyurethane sponge as precursor with small amount of titanium powder, reduced iron powder and carbonyl iron powder as the sintering additives. Porous ceramic composition optimization, influences of pore size of polyurethane sponge and slurry coating times on the porosity and skeleton diameter of TiC porous ceramics were studied. Bi-continuous phase TiC/Fe composites were prepared by pressureless infiltration method. Infiltration process and its mechanism was studied. Then the phase composition of the composites were analyzed. Macro structure and microstructure of the composites were observed, and basic mechanical properties of the composites were also tested.Results show that Ti and Fe can effectively eliminate the carbon residue decomposition of organic matter in porous ceramics by generating TiC and Fe3C in-situ, and Fe can effectively improve the strength of the porous ceramics. The structure of TiC porous ceramics is complete, and the porosity and the diameter of TiC skeleton are controllable. In the process of infiltration, some oxides were generated in the interface of porous ceramics and Fe block by reaction between metal and adsorbed oxygen, which obstructed the infiltration of Fe to porous ceramics. Adding suitable amount of C and vacuum environment can reduce the formation of oxide, and make the impregnation smoothly.Bi-continuous phase TiC/Fe composites with a multi-scale three-dimensional network structure was achieved through vacuum infiltration method. There is a good combination between TiC and Fe. A gradient hardness distribution in two-phase combining area was shown. The composite has good mechanic performance. The compressive strength, bending strength and tensile strength of a TiC/Fe composite prepared by 90 PPI sponge precursors are 658MPa, 590MPa and 271MPa respectively, and which are superior to the bi-continuous phase SiC/Fe composites and particle reinforced TiC/Fe composites prepared by others.