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JMEPEG https://doi.org/10.1007/s11665-018-3404-9

Study on Microstructures and Mechanical Properties of Foam Titanium Carbide Ceramics Fabricated by Reaction Sintering Process Yana Ma, Chonggao Bao, Jie Chen, Suocheng Song, and Longhao Han (Submitted December 21, 2016; in revised form March 29, 2018) Foam titanium carbide (TiC) ceramics with a three-dimensional network structure were fabricated by the reaction sintering process, in which polyurethane foam was taken as the template, and TiO2 and phenolic resin were used as the reactants. Phase, microstructures and fracture morphologies of foam TiC ceramics were characterized by x-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The results show that when the mass ratios of phenolic resin and TiO2 (F/T) are (0.8-1.2): 1, foam TiC ceramics with pure TiC phase can be formed. As the F/T ratios increase, crystal lattice parameters of fabricated foam TiC ceramics become bigger. When the value of F/T decreases from 1.2 to 0.8, grain size of TiC grows larger and microstructures get denser; meanwhile, the compressive strength increases from 0.10 to 1.05 MPa. Additionally, either raising the sintering temperatures or extending holding time can facilitate the completion of the reaction process and increase the compressive strength. Keywords

foam ceramics, mechanical property, microstructure, reaction sintering, titanium carbide

1. Introduction Foam ceramics possess attractive properties, such as low mass, low density, high surface area, excellent thermal stability and low thermal conductivity; therefore, they are widely used as heat exchangers, filters, reactors, catalyst carriers and surgical implants in industries, environmental protection and biomedical practices (Ref 1-6). Titanium carbide (TiC) is a typical transition metal carbide. Due to the coexistence of the ionic bond, the covalent bond and the metallic bond, TiC simultaneously possesses characteristics of high hardness, high melting point, good conductivity, corrosion resistance, etc. (Ref 7, 8). Meanwhile, TiC ceramics have a good wetting ability with metal, e.g., the wetting angle of TiC and molten Fe (1490 C) is 28. Therefore, foam TiC ceramics can be used to synthesize ceramic-metal composites (Ref 9, 10). Moreover, foam TiC ceramics have strong adsorption capability and can effectively adsorb organic and inorganic substances; thus, they are also used to purify water (Ref 11) and high temperature exhaust gas. Additionally, TiC coating can promote the osseointegration in plastic surgery on the human body, which indicates that foam TiC ceramics have good prospects for biomedical applications (Ref 12). Many methods have been proposed to fabricate foam ceramics, such as pore forming agent method, foaming method, template method, sol–gel method, self-propagating high temperature synthesis and organic foam impregnation method, etc.

(Ref 13-17). Among them, organic foam impregnation method is widely used, with which one can get foam ceramics with larger pores, higher porosity and three-di