Reaction between MgO-SiO2 refractory material and Fe-Al alloy

The interaction between molten Fe-Al alloy containing 5.1 wt.% aluminium and MgO-SiO2-based refractory was investigated. In high-frequency induction furnace at 1550 °C refractory samples were immersed in liquid alloy for 1 min, 2 min, 10 min, 20 min, 30 min and 60 min. Scanning electron microscope was employed to investigate phases at the interface and inclusions in the Fe-Al alloy. Forsterite phase in refractory was transformed to MgO·Al2O3 spinel, owing to the reduction of iron oxide and silica in forsterite by aluminium in the Fe-Al alloy at the interface. The interface layer separated locally from the refractory material and formed cluster and single particles in the Fe-Al alloy. In view on the reaction rate, the disintegration of the refractory material increased the reaction area but interfered with increasing thickness of the spinel layer. The dissolution rate of silica into the molten alloy decreased with increasing the reaction time because of the slowed down transport of aluminium diffusing through increasing spinel layer became the rate controlling step.

Experimental Study on the Segregation of Primary Silicon from the Hypereutectic Al-Si Melts in the Electromagnetic Directional Solidification

Solar grade silicon and modified Al-Si alloys are widely used in the world. These two favored materials are expected to obtain by the electromagnetic directional solidification of hypereutectic Al-Si melts. The segregation of hypereutectic Al-Si alloy is feasible with respect to the process of either pull-up or drop-down in electromagnetic directional solidification. To explore the segregation efficiency, experiments have been conducted in a high-frequency induction furnace with different pulling conditions of hypereutectic Al-Si melts. The results show that the segregation efficiency of dropping-down is higher than that of pulling-up; the slower dropping-down rate lead to higher segregation efficiency in the electromagnetic directional solidification; increasing the temperature gradient may promote the separation efficiency. A separation mechanism model responsible for the formation of the distribution of primary silicon in the cross-sections is also proposed. Wish to provide theoretical basis for the more efficiency of the segregation of hypereutectic Al-Si melts.

Cu@SiO2 nanowires: synthesis, cathodoluminescence and SERS response

Cu@SiO2 nanowires have been fabricated on a Cu substrate via simple thermal evaporation of SiO within a high-frequency induction furnace.

Application of Induction Heating to Boriding

Newly developed boriding process, which was performed by heating the metal using high-frequency induction furnace then melt the salt consisted of borax, carborundum and silicon carbide, was applied to several kinds of steels in order to find its feature. The study was carried out on the effect of chemical composition in steels and salts on the properties of the boride layer. Thick layer was obtained by using the salt containing carborundum. Increasing chromium content of the steels inhibited boriding and consequently needle-like boride layer changed into smooth one. Induction heating process offer thicker boride layer than the conventional immersion method.

Foaming Characteristics of Al-Mg Alloy Foam

Al-Mg alloy foam used in this study was prepared, and Al-Mg alloy was melted by using a high-frequency induction furnace. Thickening and foaming agent were added to the molten Al-Mg alloy at a specific temperature, which was stirred. For uniform distribution of thickening and foaming agent, the impeller was rotated with high-speed about 400-1000rpm. When left in a furnace for a specific period after uniform dispersion of the foaming agent, gas was generated from the foaming agent and the cell size and distribution inside. We determined the structure of Al-Mg alloy foam using CT(Computed Tomography). The structure of Al-Mg alloy foam has homogeneous cell size at the bottom, larger cell size in the middle, and oalescence cell in the top part. To prevent this phenomenon, the viscosity and surface tension of the melt of Al-Mg alloy were controlled.

Effect of Particle Size on the Extraction of Metallic Components from Oxidized PCB in High Frequency Induction Furnace

It is generally well known that PCB (Printed Circuit Board) is a complex mixture of various metals mixed with various types of plastics and ceramics. Accordingly, it is very important to extract metallic components from used PCB’s from the point of view of recycling the used resources as well as the environmental protection. In this study, a high temperature pyro-metallurgical process was investigated to extract valuable metallic components from the used PCB’s. For this purpose, used PCB’s were shredded and oxidized to remove plastic materials, and then, a high frequency induction furnace was used to melt and separate metallic components in molten state from the remaining oxides. After the oxidation of the used PCB, 30.6wt% SiO2, 19.3wt% Al2O3 and 14wt% CaO were analyzed as major oxides, and thereafter, a typical composition of 32wt%SiO2-20wt%Al2O3-38wt%CaO -10wt%MgO was chosen as a basic slag system for the separation of metallic components Moreover, in order to understand the size effect on the extraction of metallic components, oxidized PCB’s were further milled, and then, melted. As a result, it was found that the size of oxidized PCB’s was needed to be less 0.9mm to make a homogeneous liquid slag and to recycle metallic components over 95%.