Papers by Keyword: Titanium Silicon Carbide

Abstract: Inter-metallic compound of Ti₃SiC₂ was produced via modified-SHS (self-propagating high temperature synthesis). Elemental powders of titanium, silicon and graphite were weighed according to their stoichiometric ratios (3:1:2) respectively. These powders were ball milled for 1 hour, then compacted into cylindrical shape. Synthesis of Ti₃SiC₂ was carried out by using arc melting method. The effect of different arc melting time of 10, 30 and 60 seconds was studied. Phase formation and microstructure were analyzed by using XRD and SEM. The formation of Ti₃SiC₂ was confirmed by XRD, and the SEM micrograph shows that the grain is in needle shape. XRD result also shows that the impurities are present in all the samples. TiC appeared to be the common and dominant impurity in all samples, with relatively low intensities in Ti₅Si₃ and TiSi₂ phases. Some raw materials phase was still existed in sample arc melted for 10 and 30 seconds. Hence, it can be deduced that the raw materials had not yet fully taking part in the formation of Ti₃SiC₂.

Abstract: High purity polycrystalline titanium silicon carbide (Ti3SiC2) was synthesized by spark plasma sintering (SPS) with additive of Aluminum at low temperature of 1100~1300oC. XRD results showed that the content of Ti3SiC2 in the synthesized bulks increased with the addition of Aluminum, however, the lattice parameters of Ti3SiC2 samples with different amounts of additive exhibited scarcely change. With a starting powder of 1Ti/1.2Si/2TiC/0.1Al (molar ratios), dense Ti3SiC2 ceramic (98vol.%Ti3SiC2) was obtained by sintering at 1100oC for 5min under a pressure of 30MPa. Fine Plate-like grains of the samples with sizes of 2~6μm could be identified by scanning electronic microscope (SEM).

Abstract: Using the hot pressing method, the Ti3SiC2 materials having fine and coarse grains were synthesized from TiC0.6 and Si powders, and the Ti3AlC2 materials having fine and coarse grains were also synthesized from TiC0.6 and Al powders. The cyclic oxidation between 900 and 1200oC for 40 hr in air resulted in the formation of an outer TiO2 layer and an inner (TiO2+ amorphous SiO2) mixed layer for Ti3SiC2, and the formation of an outer TiO2 layer and an inner (TiO2+ Al2O3) mixed layer for Ti3AlC2. The effect of the grain size on the cyclic oxidation resistance was not significant.

Abstract: The contact fracture behaviors of fine-grained Ti3SiC2 and coarse-grained high purity Ti3SiC2 are examined by the Hertzian indentation and Vickers indentation technique. The Vickers hardness of bulk Ti3SiC2 is as low as 5.3~6.3 Gpa, and the Hertzian contact stress-strain curves for Ti3SiC2 deviate much from linearity, which resembles the fracture behavior of a ductile metal rather than a brittle ceramic. The contact damages by both Vickers indentation and Hertzian indentation reveal a fairly good plastic deformation nature of Ti3SiC2. Un-reacted TiCx in fine-grained Ti3SiC2 may impede the plastic deformation by slip along basal plan inside Ti3SiC2 grain, making Ti3SiC2 less plastic under loading.

Abstract: Fine-grained and coarse-grained Ti3SiC2 materials were synthesized by hot pressing using TiC0.67 and Si powders as starting materials. The oxidation between 900 and 1100oC in air resulted in the formation of an outer TiO2 (rutile) layer and an inner mixed layer of TiO2 and amorphous SiO2, accompanying the liberation of carbon into the air. Fine-grained Ti3SiC2 displayed better oxidation resistance than coarse-grained one, with activation energies of 376.5~380 kJ/mol for oxidation.