| Mechanochemistry has attracted much attention in the material field in the past three decades. However, most researches have focused on the solid-solid and the solid-gas reactions. In the beginning of the paper, the principles and characteristics of mechanochemistry and its related applications were reviewed. On the basis of the mechanochemistry theory combined with thermochemistry, a novel milling technology, defined as solid-liquid reaction milling, was developed to prepare the solid-state intermetallic compound powders by reacting the milling medium with liquid-state metal at a certain temperature range. Furthermore, some element powders with the same composition as the milling medium were also added to accelerate the reaction.Eleven systems were investigated by the solid-liquid reaction milling process. Based on the experimental results and the correlative physical chemistry reaction theory, some solid-liquid reaction models were established as well as their mechanisms. Moreover, the distinctions between solid-liquid reaction milling and mechanical alloying were revealed thoroughly. The significant results were enumerated as follows:(1) For the Fe-Sn binary alloy systems, some pure Sn scraps (99.9%, 200g) and pure Fe (99.9%) were served as the starting material and the milling medium (including the milling pot and balls, favorable to avoid contamination) respectively. All the solid-liquid milling experiments were conducted with the weight ratio of ball-to-material of 30:1 and the rotation speed of 80rpm. The species of the as-milled products varied with the milling temperature increase and time prolongation. Pure solid-state FeSn2, FeSn Fe3Sn2, Fe1.3Sn phases were generated respectively after milling 48h at 593K, 64h at 873K, 72h at 1033K and 72h at 1073K. The addition of pure Fe powders (25wt%) contributed to an accelerated reaction and hence the milling time forming the entirely solid-state FeSn2, FeSn Fe3Sn2 and Fe1.3Sn phases decreased to 24h, 48h, 64h and 64h at the corresponding temperature respectively. As far as the Fe-Zn & Fe-Sb binary alloy systems were concerned, pure Zn and Sb scraps (>99.5%, 200g) were selected as the starting materials respectively. The weight ratio of ball-to-material was adjusted to 12:1. Pure solid-state FeZn13, FeZn10.98, FeZn8.87and Fe11Zn40 powders were obtained after milling 48h at 723K, 823K, 923K and 993K respectively. Similar to the Fe-Zn system, pureFeSb2 and FeSb powders were obtained after milling 48h at 923K and 1043K respectively. Likewise, the addition of pure Fe powders (20wt.%) to the Zn or Sb melt enhanced the reaction velocity and reduced the milling time to obtain pure intermetallic compound powders.(2) For the X-Al binary alloy systems (X=Ti, Ni or Fe), some pure Al scraps (99.5%, 200g) were served as the starting material and milled by Ti, Ni and Fe ball respectively. The weight ratio of ball-to-material was adjusted to 14:1 and the milling temperature was settled at 973K. After milling 12h, solid-state TiAl3 and T19Al23 intermetallic powders were obtained in the Ti-Al binary system and no residual Al liquid was detected; Whereas completely solid-sate T1AI3 occured after milling 24h. As for the Ni-Al binary system, the solid-state M2Al3 and NiAl3 mixture was formed and no liquid phase was detected after milling 12h. But for the Fe-Al binary system, the residual Al disappeared and the Al13Fe4, Fe2Al5and FeAl2 mixture occurred after milling 24h. The Al13Fe4 phase was transformed to Fe2Al5 and FeAl2 after milling 48h. The addition of pure metal powders with the same composition as the starting metal had an alike effect on the reaction velocity.(3) Pure binary alloy (Al-Cu & Al-Si) ingots (>99.5%, 200g) were served as the starting materials respectively. Fe was selected as the milling medium. The weight ratio of ball-to-material and the rotation speed were fixed on 12:1 and 80rpm respectively. The solid-state Al7Cu2Fe and Al13Cu4Fe3 mixture occured and the Al2Cu liquid disappeared after milling the eutectic Al-33.2wt%Cu melt for... |
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