Reactions in the system TiCx-TiB2

Combustion synthesis of TiCx–TiB2 composites with hypoeutectic, eutectic and hypereutectic microstructures

“…Repeated experiments gave the similar compositions and microstructures, implying that the eutectic composition in the TiC 0.77 -TiB 2 system is around 36.7 mol.% TiB 2 , as inferred from the quantitative XRD results. This result is in general agreement with the compositions experimentally determined by Beratan 10 and theoretically calculated by Gusev,11 as presented in Table 1, but is somewhat different from the compositions measured by Rudy and Windisch 8 and Ordanyan et al 9 Moreover, the eutectic composition of 28 mol.% TiB 2 measured by Li et al 12 obviously conflicts with the above results. Fig.…”

“…On the other hand, TiC x -TiB 2 has been demonstrated to be a eutectic system [8][9][10][11][12] and the eutectic composition and temperature of this system are significantly dependent on the composition of TiC x . 8,11 According to the Ti-C phase diagram, 13 the value of x in TiC x ranges from 0.47 to 1.0 and the eutectic point of the TiC x -TiB 2 system, as indicated in Fig.…”

Reaction Behavior and Mechanism during Self-Propagating High-Temperature Synthesis Reaction in an Al-TiO2-B4C System

“…The products display an agglomeration structure, within which a fine eutectic-type structure was observed (insert in Figure (a)). It was reported by Ordanyan et al [19] that the eutectic reaction could take place in the TiC x -TiB 2 system at temperatures ranging between 2653 and 2793 K as the stoichiometry (x) of TiC x varied from 0.68 to 0.95. Instead, Gusev [20] argued that the eutectic reaction could occur at temperatures between 2936 and 2961 K for compositions around 60 mol pct TiC x and 40 mol pct TiB 2 based on theoretical calculations.…”

“…[1] and (2) no eutectic transformation occurs among the resultant TiC, TiB 2 , and Al 2 O 3 phases [19][20][21] and no reaction between Al 2 O 3 and excess Al, [22] the values of adiabatic temperature (T ad ) could be calculated using thermodynamic data from Reference 23 based on the following equation: [3] DH 298…”

Ceramic composites: TiB2-TiC-SiC

“…The first evidence is that no reaction at all occurred between TiB2 and SiC since the two tablets fall apart once pushed out of the die. Ordon'yan [15] found a very small solubility of TiB2 in TiC at temperatures equal or higher than 2100 ~ Since both materials exhibit a very similar coefficient of thermal expansion (CTE) ( ~ 8 10-6 K -1 ), no interface stresses are generated during cooling. How-ever, the two other diffusion couples were found to be firmly bonded.…”