Masashi Nakamoto

Measurement of the surface tension of liquid Ga, Bi, Sn, In and Pb by the constrained drop method

Abstract The effect of the droplet size on the accuracy of surface tension measurement by the sessile drop method is discussed for liquid metals through a simulation by using the Laplace equation. It is found that with increasing size of the droplet, a higher accuracy of the measured value of the surface tension can be obtained. In order to make a large droplet of liquid metals, the constrained drop method with a special crucible shape was applied to measure the surface tension of liquid Ga, Sn, Bi, In, and Pb. The uncertainty of the measured surface tension was within 1%. The temperature dependences of the surface tension of liquid Ga, Sn, Bi, In, and Pb were obtained in the present experiment as follows: Ga: σGa = 737 −0.062T mN/m (823 ≤ T≤  993K)Sn: σSn = 579 −0.062T mN/m (723≤ T≤  993K)Bi: σBi = 417 −0.070T mN/m (773 ≤ T≤  873K)In: σIn = 600−0.082T mN/m (673 ≤ T≤  993K)Pb: σPb = 499 −0.089T mN/m (757 ≤ T≤  907K)

Design of Lubricants Using Waste Slag in Large Strain Addition Strip Processing for Ultrafine-Grained Steels

Aiming to design new lubricants in the large strain addition strip process for ultrafine-grained steels, we tested the possibility of using waste slag, which is generated largely from iron and steelmaking processes, municipal waste treatments and so on. We then focused our attention on the slag containing water as the new lubricant. Slag satisfies the requirement of biting the workpiece stably, which cannot be achieved with conventional lubricants, because slag is stable as a solid phase of high hardness at the biting temperature in the strip process (100~200oC). In addition, slag contains water under hydrothermal conditions to provide lubricating effects by lowering glass transition temperature. In the present study, the effect of additive components (Al2O3, B2O3, CaO, MgO, K2O, Li2O and V2O5) on the glass transition temperature of a SiO2-Na2O-based slag containing water was examined. The glass transition temperature of the slag containing water is 150~300 oC, which is lower than that of original slag. It was also found that the glass transition temperature depends on the additive components to the slag.

Extraction of Phosphorus from Dephosphorization Slag

In Japan, steelmaking slag is one of the most important secondary phosphorus (P) resources. The annual amount of P removed into steelmaking slag (c. 114 kt P/a) is approximately 2.8 times more than that of P imported as phosphate (Pi) rock to Japan. Increasing attention has been paid to P recovery from dephosphorization slag for mitigating the Japan’s dependency on P import. This chapter describes the smelting reduction technology for extracting P from dephosphorization slag into iron. The potential of this technology has been examined using a pilot-scale test furnace having the capacity to treat dephosphorizing slag at 2 t/day. P could be extracted from dephosphorization slag, forming Fe-P alloy with the P content of approximately 10 wt%.

Melting Behavior of Sn–Bi Alloy Powder Compacts Observed Using Optical Dilatometry

Abstract The melting behavior of Sn – Bi alloy powder compacts was observed using optical dilatometry. The change in standard deviation of compact width with temperature obtained by dilatometry was used to evaluate the melting behavior by considering the factors in the shape change of the compact under heating. The effects on melting behavior of alloy composition, particle size and pressing load at compacting are discussed in this study. The difference in composition affected the melting behavior in accordance with the phase diagram. Smaller particle size showed a lower degree of melting. The effects of these two parameters, viz. composition and particle size, however, are highly dependent on surface oxidation of powders. The influence of surface oxidation, on the other hand, was reduced by producing the compacts with a higher pressing load.