Reaction Behavior of Porous TiAl3 Intermetallics Fabricated by Thermal Explosion with Different Particle Sizes

Porous TiAl3 intermetallics were prepared by the thermal explosion (TE) and space holder method with different particle sizes of Ti and Al powders, and their reaction behaviors were investigated. The results showed that with the increase in the particle size of the Ti and Al powders, the interfacial contact between the particles decreased, resulting in low interfacial energy and reaction activity, making the process difficult to initiate. Meanwhile, the heat flow rose from 358.37 J/g to 730.17 J/g and 566.74 J/g due to the extension of the solid–liquid diffusion time. The TiAl3 structures obviously expanded, and the formation of connected pore channels promoted the porosity. Only when the Ti and Al particle sizes were both small did the solid–solid diffusion significantly appear. At the same time, the TE reaction weakened, so the product particles had no time to fully grow. This indicates that the particle size of the raw materials controlled the TE reaction process by changing the solid–liquid diffusion reaction time and the degree of solid-phase diffusion.

Crystal structure and magnetic study of the complex salt [RuCp(PTA)2–μ-CN-1κC:2κN–RuCp(PTA)2][Re(NO)Br4(EtOH)0.5(MeOH)0.5]

A new RuII–ReII complex salt, μ-cyanido-κ2 C:N-bis[(η5-cyclopentadienyl)bis(3,5,7-triazaphosphaadamantane-κP)ruthenium(II)] tetrabromido(ethanol/methanol-κO)nitrosylrhenate(II), [Ru(CN)(C5H5)2(C6H12N3P)4][ReBr4(NO)(CH4O)0.5(C2H6O)0.5] or [RuCp(PTA)2–μ-CN–1κC:2κ2 N-RuCp(PTA)2][Re(NO)Br4(EtOH)0.5(MeOH)0.5] (PTA = 3,5,7-triazaphosphaadamantane) was obtained and characterized by single-crystal X-ray diffraction, elemental analysis and infrared spectroscopy. The title salt was obtained by liquid–liquid diffusion of methanol/DMSO solutions of (NBu4)[Re(NO)Br4(EtOH)] and [(PTA)2CpRu–μ-CN–1κC:2κ2 N-RuCp(PTA)2](CF3SO3). The RuII and ReII independent moieties correspond to a binuclear and mononuclear complex ion, respectively. A deep geometrical parameter analysis was performed, and no significant differences were found with earlier reports containing similar molecules. The magnetic properties were investigated in the temperature range 2.0–300 K, and the complex behaves as a quasi-magnetically isolated spin doublet with weak antiferromagnetic interactions.

Influences of silicon carbide nanowires addition on IMC growth behavior of pure Sn solder during solid-liquid diffusion

In this paper, various mass fraction (0, 0.2, 0.4, 0.6, 0.8, 1.0 wt%) of silicon carbide nanowires (SiC) were incorporated into pure Sn solder to enhance the performances of Sn solder joint. The wetting behavior, shear strength and intermetallic compound (IMC) growth mechanism of Sn-xSiC/Cu solder during solid-liquid diffusion at 250°C was investigated systematically. The experiment results demonstrated that the wettability of Sn-xSiC/Cu solder had a significant improvement when the addition of SiC was up to 0.6 wt%, and excessive additives would degrade the wettability of the composite solder. The formation of the Cu6Sn5 IMC layer was observed at the Sn-xSiC solder/Cu interface. Meanwhile, SiC as an additive was conducive to restraining the growth of interfacial IMC during soldering process and the IMC thickness overtly fell down after doping 0.8 wt% SiC into Sn solder. Moreover, SiC addition would contribute to enhancing the mechanical performance of Sn solder joint. The fracture mechanism of solder joint changed from a mix of brittle and ductile fracture to a characteristic of typical ductile fracture.