Search

In order to clarify the reaction behaviour systemically between CaO and dephosphorisation slag, the solid CaO piece was dipped into the liquid slag and reacted for 5–300 seconds at 1573 K, the reaction mechanism between homogeneous CaO–SiO2–FeO–P2O5 slag and CaO was investigated in the present study. The results shows that 2CaO·SiO2 and 3FeO·P2O5 are the main phases in dephosphorisation slag, the enrichment phase of phosphorus were formed very fast in

In the present work, a melt spinning technique was employed to produce Ti51·5Ni48·5 shape memory ribbons. Two types of Ti2Ni particles were observed using high resolution transmission electron microscopy, and a model is proposed based on the microstructural observations. For the large Ti2Ni particles (∼300–500 nm), it is suggested that they are the product of an L32(Ti)+TiNi→Ti2Ni peritectic reaction, where the subscript stands for the Ni content. However, in the case of small particles, novel structures composed of a Ti-rich core and an amorphous shell layer are observed, which are the result of the rapidly solidified L(Ti)→β(Ti)+L24(Ti) and L24(Ti)→β(Ti)+Ti2Ni divorced eutectic process.

The effect of TiO2 additive on the synthesis of dense forsterite is investigated in the present work. As the intermediate phase formed in the synthesis process, the magnesium titanate plays a very important role in the improvement of the formation and densification of forsterite. Notably, it finally transfers into a high melting point second phase when segregated at a higher sintering temperature. The addition of TiO2 improves the density of forsterite at a low temperature by liquid-phase sintering and may reduce or even eliminate the defects of liquid phase-sintering by the segregation of the liquid phase at high temperature.

An exact solution was developed for a quasi-steady-moving-interface heat transfer problem in laser transformation hardening by a beam customized to a flat-top rectangular shape. The absorption and release of the latent heat were taken into account. The solution provided the body temperature, heating rate, and subsequent cooling rate. Using the IT and CCT diagrams, the rapid austenitization and pearlitic/martensitic phase transformation were determined for prediction of the hardening effect. In the experimental study, a diffractive optical kinoform (DOK) was used to customize a conventional Gaussian laser spot beam to a flat-top rectangular beam. A reasonable agreement between the theoretical predictions and the experimental measurements was obtained.

Excimer laser surface treatment of Ti–6Al–4V alloy was conducted with the aim of improving the pitting corrosion resistance of the alloy. Laser surface treatment was performed under two different gas environments, argon and nitrogen. The microstructure, phase and composition of the modified surface structure were analysed using TEM, XRD and EDX; the electrochemical behaviours of the untreated and the laser-treated specimens were evaluated by electrochemical polarization tests. Excimer laser surface treatment significantly increased the pitting potential of the Ti alloy, especially when the material was treated in argon gas, while a seven-fold reduction in corrosion current was obtained when the material was treated in nitrogen gas. These improvements are considered to be primarily due to the reduction of solute partitioning effect of detrimental Al segregated to the α phase. The N 2 -treated specimen, although it had the lowest corrosion current, had a pitting potential some 100 mV lower than that of the Ar-treated specimen. This is considered to be due to TiN precipitates acting as galvanic cathodes at high corrosion potentials.