Bingsheng Xu’s research while affiliated with China National Institute of Standardization and other places

The innovative slag splashing technique enhances the recycling of CO 2 in the steel industry. However, thermodynamic experiments overestimate CO 2 conversion because the temperature drop in the process is not taken into account. Therefore, FactSage is employed to reevaluate it. Calculations are validated by comparison with experiments. It is found that employing CO 2 for the slag splashing process leads to a decrease in equilibrium temperature. Increasing the carbon addition enhances CO generation and CO 2 conversion but results in a further reduced temperature. Elevating the temperatures of the slag and CO 2 has no effect on CO generation and CO 2 conversion. However, it proves beneficial for increasing the equilibrium temperature. As the most effective measure, increasing the FeO content in the slag improves CO 2 conversion while significantly lowering the slag solid fraction. When the initial FeO content is 17.24 mass%, the initial temperature is 1873 K, and the CO 2 temperature is 300 K, the optimal carbon addition is 1.5 mass%. By increasing the slag and CO 2 temperatures and elevating the initial FeO content, the carbon addition can reach 3.0 mass%, and CO 2 conversion reaches 53.29%.

Asymmetric composite tubular membranes were prepared with SiC as the support body and mullite as the membrane layer. The asymmetric mullite/SiC composite filter tube membranes were characterized by different analytic techniques. The mullite membrane was prepared as a layer on the SiC support with a thickness of about 175 ?m, pore size of about 1-10 ?m and porosity of 9.9%. The SiC support tube had a pore size of about 20-150 ?m and porosity of 19.0%. After 360 days of high-temperature flue gas filtration, the most available pore size of the mullite/SiC composite filter tube membrane reduces from 45.2 to 36.4 ?m (the reduction rate of about 19.4%). Analysis of the dust collected by back-blowing revealed that the dust particle size range was between 0.1-100 ?m and about 50%of the dust particles were below 2.5 ?m in size. The average capture rate of dust can reach 98.4%, indicating that the asymmetric mullite/SiC composite filter tube membrane has excellent filtration performance for the dust below PM2.5 in the high-temperature complex flue gas.

The interfacial characteristics and microstructure of solder/substrate is an important indicator for welding performance. Due to weak gravity-induced convection under microgravity condition, Marangoni convection effect becomes more obvious, which significantly influences the interfacial characteristics and solidification microstructure of alloy by controlling bubble behavior and mass transfer in the melt. To obtain strong Marangoni convection, Sn–3.5Ag/Sn–17Bi–0.5Cu and Sn–3.5Ag/Sn–10Sb alloys with different surface tension are constructed. The alloys are solidified on Cu ring substrate under space microgravity condition (SJ-10 satellite) to study the reaction mechanism of melt/substrate interface and microstructure evolution of alloys based on the analysis of the structure of intermetallic compounds and element distribution in solidified alloy. The corresponding wetting experiment of Sn–3.5Ag and Sn–17Bi–0.5Cu or Sn–10Sb on the Cu ring ground is done under ground. The results indicate that, under microgravity condition, a large number of fine pores appear in the alloys, and a lot of scalloped or small rod-like crystals are formed at alloy/substrate interface. Many big rod-like crystals are also formed in the bulk of alloy. The elementary analysis results show that, after Sn–3.5Ag/Sn–17Bi–0.5Cu alloy being melted, Ag is evenly diffused and distributed in the bulk phase, Bi is also evenly diffused and block aggregation is formed, which is mainly clustered at the outer edge of interface layer at the bulk phase side. There are three layers of intermetallic compound at the interface of alloy and substrate, that is, the thin Cu41Sn11 transition layer near the substrate side, the thick Cu3Sn layer in the middle, and Cu6Sn5 layer near the solder. Two layers of substances are formed on the ground. That is, the thin Cu3Sn transition layer near the substrate side and the Cu6Sn5 layer near the solder. Similarly, after Sn–3.5Ag/Sn–Sb alloy being melted, interface reaction happens on the melt/substrate interface. And three layers of substances are also formed: the thin Cu41Sn11 layer near the substrate side, the Cu3Sn in the middle side and the Cu6Sn5 layer near the solder side. The Sb element is more enriched in the alloy Sn in the other area, but in the internal rod-like crystal of bulk phase, Sn is not detected.

Purpose This research aims to provide a theoretical method and data supports for a future study on interfacial reaction mechanism and spreading mechanism between molten solder and V-shaped substrate, which also gives guidance for those complicated welding operation objects in brazing technique. Design/methodology/approach Wetting experiments were performed to measure the contact angles at different temperatures of molten Sn-3.0Ag-0.5Cu wetting on the quartz substrate with an included angle of 90°. According to the experimental results, the theoretical spreading morphology of molten solder on V-shaped substrate at corresponding temperature was simulated by Surface Evolver. Findings The theoretical morphology profiles of the molten solder sitting on the V-shaped substrate are simulated using Surface Evolver when the molten solder reaches spreading equilibrium. The spreading mechanisms as well as the impact of surface tension and gravity on interfacial energy of the molten solder wetting on the V-shaped groove substrate are also discussed where theoretical results agree well with experiment results. The contact area between the gas and liquid phases shows a tendency of first increasing and later decreasing. Otherwise, the spreading distance and the height of the molten solder increases as the droplet volume increases as the included angle and the contact angle are given as constants, and both the interfacial energy and the gravitational energy increase as well. This research has a wide influence on predicting the outcomes in commercial impact and also gives guidance for those complicated welding operation objects in brazing technique. Research limitations/implications It is of very important significance in both science and practice to investigate the differences between the flat surface and V-shaped surface. Some necessary parameters including intrinsic contact angle and surface tension need to be directly measured when the droplet spreads on the flat surface. The relevant simulation conclusions on the inherent characteristics can be given based on these intrinsic parameters. Compared with the flat surface, the V-shaped substrate is chosen for further discuss on the effects of gravity on the droplet spreading behavior and the changes of apparent contact angle which can only occurs as the substrate is inclined. Therefore, this research provides theoretical method and data supports for a future study on interfacial reaction mechanism and spreading mechanism between molten solder and substrate. Practical implications The research is developed for verifying the accuracy of the model built in Surface Evolver. Based on this verified model, other researches on the spreading distance along y-axis and the contact area that are especially difficult to be experimentally measured can be directly simulated by Surface Evolver, which can provides a convenient method to discuss the changes of horizontal spreading distance, droplet height and contact area with increasing the included angle of V-shaped substrate or with increasing the droplet volume. Actually, the modeling results are calculated for supplying the theoretical parameters and technical guidance in the welding process. Social implications This research provides theoretical method and data supports for a future study on interfacial reaction mechanism and spreading mechanism between molten solder and substrate, which has a wide influence on prediction the outcomes in commercial impact and also gives guidance for those complicated welding operation objects in brazing technique. Originality/value Surface Evolver, can also be used to discuss the structure and spreading mechanism of droplets on V-shaped substrates, which have not been discussed before.