Mechanical‐Alloying‐Assisted Synthesis of Ti₃SiC₂ Powder

Abstract

Mechanical alloying (MA) has been used to synthesize Ti 3 SiC 2 powder from the elemental Ti, Si, and C powders. The MA formation conditions of Ti 3 SiC 2 were strongly affected by the ball size for the conditions used. MA using large balls (20.6 mm in diameter) enhanced the formation of Ti 3 SiC 2 , probably via an MA-triggered combustion reaction, but the Ti 3 SiC 2 phase was not synthesized only by the MA process using small balls (12.7 mm in diameter). Fine powders containing 95.8 vol% Ti 3 SiC 2 can be obtained by annealing the mechanically alloyed powder at relatively low temperatures.

Reaction in Ti3SiC2 powder synthesis from a Ti–Si–TiC powder mixture

“…Commercial powders of Ti (10 m in average size, 99.9% in purity), Si (2-3 m in average size, 99% in purity), and Ti-Si-C FS process at 1200-1300 • C for 2 h in flowing argon 82.5 [19] Ti-Si-C 400 MA +1000 • C 1 h annealing 95.8 [20] TiC (2-5 m in average size, 99% in purity) with molar ratios of 2:2:3 were used as the starting material and mixed by a Tubular shaker mixer in argon atmosphere for 24 h. Powder mixture was put into alumina crucible for the following treatment performed in a vacuum furnace (<3 × 10 −3 Pa). To simulate the heating process, some powders were heated at various intermediate temperatures in the range of 700-1200 • C for 1 s followed by the furnace cooling, while others were heated at 1210 • C for various durations.…”

“…Moreover, with Ti 3 SiC 2 powder it is possible to develop Ti 3 SiC 2 dispersion-strengthened alloys to overcome poor mechanical properties for some potential high temperature candidate materials, such as NiAl and MoSi 2 . For the Ti 3 SiC 2 powder synthesis, starting materials of elemental Ti-Si-C powder mixtures were applied by Sun and Zhou using a solid-liquid (S-L) reaction process [18] and a fluctuation synthesis (FS) method [19], and by Li et al using a mechanical alloying (MA) method followed by the post-annealing treatment [20]. Table 1 summarizes the reported results for the synthesis of Ti 3 SiC 2 -based powders.…”

Synthesis of Ti3SiC2 powder from 1Ti/(1+x)Si/2TiC powder mixtures

“…To improve the Ti 3 SiC 2 content, following treatments, including the removal of TiSi 2 by HF solution and the removal of TiC by oxidation at 500 • C in air followed by the dissolution in hot (NH 4 ) 2 SO 4 + H 2 SO 4 solution, were used. Also with Ti/Si/C powder mixture as the starting material, a mechanical alloying (MA) method followed by the post-annealing treatment was used by Li et al to synthesize Ti 3 SiC 2 powder, and powder with about 95.8% Ti 3 SiC 2 can be synthesized [20].…”

Low-temperature fabrication of high purity Ti3SiC2

“…1 may be an indication that SHS reactions [10,11] occurred during the milling process, and excess Al addition suppressed such reactions.…”

“…High purity Ti 3 SiC 2 can be fabricated at lower temperature by combining mechanical alloying and the means of heat-treating or sintering. Jingfeng Li et al synthesized Ti 3 SiC 2 with the purity of 95.8 vol% by mechanical alloying of the 3Ti/Si/2C powder mixture for 10 h, and subsequent vacuum heat-treating at 1000 • C for 1 h [10]. Orther fabricated single-phase Ti 3 SiC 2 by sintering using a 1 h ball-milled powder mixture consisting of 3Ti/(1 + x) Si/2C(0.1,0.2,0.3) at 1350 • C for 2 h [11].…”