Xue Xiangxin

Oxidation of Silicon and Boron in Boron Containing Molten Iron

A new process of directly smelting boron steel from boron-containing pig iron has been established. The starting material boron-containing pig iron was obtained from ludwigite ore, which is very abundant in the eastern area of Liaoning Province of China. The experiment was performed in a medium-frequency induction furnace, and Fe2O3 powder was used as the oxidizing agent. The effects of temperature, addition of Fe2O3, basicity, stirring, and composition of melt on the oxidation of silicon and boron were investigated respectively. The results showed that silicon and boron were oxidized simultaneously and their oxidation ratio exceeded 90 % at 1 400 °C. The favorable oxidation temperature of silicon was about 1 300–1 350 °C. High oxygen potential of slag and strong stirring enhanced the oxidation of silicon and boron.A new process of directly smelting boron steel from boron-containing pig iron has been established. The starting material boron-containing pig iron was obtained from ludwigite ore, which is very abundant in the eastern area of Liaoning Province of China. The experiment was performed in a medium-frequency induction furnace, and Fe2O3 powder was used as the oxidizing agent. The effects of temperature, addition of Fe2O3, basicity, stirring, and composition of melt on the oxidation of silicon and boron were investigated respectively. The results showed that silicon and boron were oxidized simultaneously and their oxidation ratio exceeded 90 % at 1 400 °C. The favorable oxidation temperature of silicon was about 1 300–1 350 °C. High oxygen potential of slag and strong stirring enhanced the oxidation of silicon and boron.

Antibacterial Ceramic Fabricated by the Ti-Bearing Blast Furnace Slag

The comprehensive utilization of Ti-bearing blast furnace slag was a technological problem that was discussed by many researchers for years. Not only does the slag take the land resources massively, but it causes environment pollution. The antibacterial ceramic materials were mainly fabricated by Ti-bearing blast furnace slag as main materials and combined with kaolinite, Potassium feldspar, pyrophylite and quartz sand, to solve the technological problem in this paper. The slag proportion and optimum sintering technology for ceramics in sintering process were obtained by single factor experiment. And, it was confirmed by orthogonal experiment that the shrinkage rate and water absorption are obviously affected by the quantity of slag, sintering temperature, holding time and so on. The composition and microstructure of ceramic materials were characterized by X-ray diffraction, scanning electron microscope and microscopy. It is showed that the ceramic has a good anti-bacterial for Escherichia coli, when bacteria-inhibiting ring method was used for measurement.

A New Method of Fabricating AlN-TiB2 Composite Ceramics

In this article, we study a new method of in-situ synthesis of aluminum nitride-titanium diorite (AlN-TiB2) composite ceramics by vacuum metal infiltration. The AlN-TiB2 composite ceramics were fabricated by preheating BN+TiB2 at 1,600°C for one hour before infiltrating Al alloys into the preforms in a vacuum at 1,100°C for two hours. Interfacial reactions between Al and BN were fully utilized to prepare the AlN-TiB2 composite ceramics. Residual Al and a small amount of aluminum dodecaboride (AlB12) were found. In addition, we noted that AlB12 phase clustered around the TiB2. But we also observe AlN at considerable distance from TiB2.

Slip Casting of α-Sialon/AlN/BN Powder Carbothermally Prepared by Boron-rich Slag-based Mixture

With boron-rich slag, silica fume, bauxite chalmette and carbon black as starting materials, ?-Sialon/AlN/BN powder was prepared by carbothermal reduction-nitridation. The powder was attrition milled to submicron size and suspended in water. The effects of yttrium oxide as a sintering aid, pH, and addition of deflocculant on the suspensions were study. Optimum slip casting properties, i.e. lowest viscosity values, the highest absolute zeta potential values, the smallest floc size and sediment volume were found at pH 10 for the powder. The suspensions were used to slip cast discs which were sintered in a nitrogen atmosphere at 1700?C for 2h. The strength was about 230MPa, the toughness 3.6 MPa?m1/2 and the hardness about 13.8GPa.