Metal powders of superlative quality, i.e. high cleanliness, rapidly solidified and spherical shape, have seen an increasing demand in the market. The leading technology for the production of such powders is the inert...Metal powders of superlative quality, i.e. high cleanliness, rapidly solidified and spherical shape, have seen an increasing demand in the market. The leading technology for the production of such powders is the inert gas atomization of metal alloy melts. To fulfill these requirements, the metal alloy is usually produced in a vacuum induction melting furnace (VI-GA = vacuum induction melting/gas atomization) and poured by means of a preheated tundish system into a gas nozzle where the metal stream is disintegrated by a high kinetic energy inert gas jet. The produced micro-droplets solidify in a free fall inside the atomization tower. For special applications, super-clean and ceramic-free metal powders can be produced by using the EIGA (electrode induction melting/gas atomization) melting- and atomizing system. As an alternative to the metal powder route, the sprayforming technology allows to produce semi-finished products in one step. In this case, the metal droplets produced by the high-energy inert gas nozzle system are directly solidified on a substrate, allowing to form billets, rolls and tubes.展开更多
A new type of rice seedling carrier named seedling-growing bowl tray made of paddy straw(SGBTMPS)was developed in China.Traditional preparation process for SGBTMPS is complex and difficult to operate.Hence,a new SGBTM...A new type of rice seedling carrier named seedling-growing bowl tray made of paddy straw(SGBTMPS)was developed in China.Traditional preparation process for SGBTMPS is complex and difficult to operate.Hence,a new SGBTMPS preparation method has been developed by using straw powder as the main raw material.In this method,modified starch-based adhesive was replaced by the binder of thermosetting adhesive,and preparation constraints such as forming pressure,forming temperature,and dwell time were decreased.The effects of factors such as glue(modified starch-based adhesive),forming pressure,forming temperature and dwell time on SGBTMPS preparation were evaluated by single factor experiment.Orthogonal experiment and comprehensive weight analyses were adopted to optimize the parameters for SGBTMPS preparation.The results showed that optimized parameters were 125% glue and 1.2 kg mixed materials with the forming pressure,temperature,and dwell time of 30 MPa,140℃ and 330 seconds,respectively.Compared with traditional preparation process,the proportioning link,preparation link,and preparation time in the new preparation process were reduced by 66.7%,33.3%,and 17%,respectively;the pot-hole percentage and the expansion ratio were increased by 0.09% and 0.05%,respectively.This study indicated that the new preparation process for SGBTMPS was simpler and easier to operate and would provide a useful reference for further research and industrialization on SGBTMPS.展开更多
Possibility of making Al-Pb alloy plate with Pb dispersed uniformly by LDC (Liquid Dynamic Compact) technology has been studied in the present paper. The relationship among the distance between nozzle and cooled base ...Possibility of making Al-Pb alloy plate with Pb dispersed uniformly by LDC (Liquid Dynamic Compact) technology has been studied in the present paper. The relationship among the distance between nozzle and cooled base plate and the atomization pressure as well as the density of the Al-Pb alloy slab is measured. The relative density of the LDC Al-Pb alloy slab can reach 90% under condition of the present experiment. Microstructure of the slab consist of equal axial grains with 15 approximately 25 μm in diameter and Pb dispersed uniformly in them. After cold or hot rolling of the slab with reduction of 50 approximately 60%, the microstructure can be densified. The rolled Al-Pb alloy plate can be compacted together with pure Al plate very well.展开更多
研究了高能球磨对Si粉微观结构和水解制氢性能的影响。球磨过程中,颗粒尺寸不断减小,非晶转变发生,晶界、内应力、位错以及晶格变形等微观缺陷不断增加,有利于提高Si粉的制氢性能;但随着球磨时间的延长,颗粒团聚趋于严重,粉末氧化不断加...研究了高能球磨对Si粉微观结构和水解制氢性能的影响。球磨过程中,颗粒尺寸不断减小,非晶转变发生,晶界、内应力、位错以及晶格变形等微观缺陷不断增加,有利于提高Si粉的制氢性能;但随着球磨时间的延长,颗粒团聚趋于严重,粉末氧化不断加剧,降低了Si粉的制氢性能。当球磨时间为1 h,Si粉具有最优的制氢性能,70℃水解时其放氢量为1 484.2 m L·g^(-1)Si,但由于水解副产物SiO_2包覆在Si表面导致其转化率为94%,无法继续完全水解。展开更多
The epoxy powder exterior anti-corrosion coating production line for bent pipes with a single (double) course production is a technologically advanced bent pipe anti corrosion method with cost efficiency, environment ...The epoxy powder exterior anti-corrosion coating production line for bent pipes with a single (double) course production is a technologically advanced bent pipe anti corrosion method with cost efficiency, environment friendliness and stable coating quality. The quality of the coating on the bent pipe fully meets the requirements of the current national and industrial standards. The application of the technology has filled the gap in the bent pipe anti corrosion coating area of China, and leads the world technologically. With this technology the coating quality of the bent pipe has greatly improved, resulting in significant social and economic benefits. With the use of the technology in various large scale pipeline projects such as the "West to East Gas Pipeline Project", it will exhibite a greater potential in the future pipeline projects with a broad application prospect.展开更多
This study was carried out to investigate the possibility of titanium alloy metal powder production using low-power plasma torches.An argon DC non-transferred arc plasma torch was designed,and numerical analysis was c...This study was carried out to investigate the possibility of titanium alloy metal powder production using low-power plasma torches.An argon DC non-transferred arc plasma torch was designed,and numerical analysis was conducted to determine the plasma jet properties and wire temperature.The highest velocities inside the nozzle attachment were between 838 and 1178 m/s.The velocities of the jets at the apex were between 494 and 645 m/s for different gas flow rates.The studied plasma gas flow rates had no significant effect on the effective plasma jet length.It was shown that the plasma jet length can be estimated by numerical analysis using the temperature and velocity changes of the plasma jet over distance.It was observed that the powders produced were spherical without any satellites.As a result of this study,a plasma torch was developed and powder production was performed successfully by using relatively low torch power.展开更多
Al-20Sn-1Cu powders were prepared by gas atomization in an argon atmosphere with atomizing pressures of 1.1 and 1.6 MPa. The characteristics of the powders are determined by means of dry sieving, scanning electron mic...Al-20Sn-1Cu powders were prepared by gas atomization in an argon atmosphere with atomizing pressures of 1.1 and 1.6 MPa. The characteristics of the powders are determined by means of dry sieving, scanning electron microscopy （SEM）, optical microscopy （OM）, and X-ray diffractometry （XRD）. The results show that the powders exhibit a bimodal size distribution and a higher gas pressure results in a broad size distribution. All particles in both cases are spherical or nearly spherical and satellites form on the surface of coarse particles. Dendritic and cellular structures coexist in the particle. With decreasing particle diameter, the secondary dendrite arm spacing （SDAS） decreases and the cooling rate increases. The particles processed under high gas atomization pressure （1.6 MPa） exhibit a lower SDAS value and a higher cooling rate than those of the same size under low gas atomization pressure （1.1 MPa）. The XRD results show that the Sn content increases with decreasing particle size.展开更多
文摘Metal powders of superlative quality, i.e. high cleanliness, rapidly solidified and spherical shape, have seen an increasing demand in the market. The leading technology for the production of such powders is the inert gas atomization of metal alloy melts. To fulfill these requirements, the metal alloy is usually produced in a vacuum induction melting furnace (VI-GA = vacuum induction melting/gas atomization) and poured by means of a preheated tundish system into a gas nozzle where the metal stream is disintegrated by a high kinetic energy inert gas jet. The produced micro-droplets solidify in a free fall inside the atomization tower. For special applications, super-clean and ceramic-free metal powders can be produced by using the EIGA (electrode induction melting/gas atomization) melting- and atomizing system. As an alternative to the metal powder route, the sprayforming technology allows to produce semi-finished products in one step. In this case, the metal droplets produced by the high-energy inert gas nozzle system are directly solidified on a substrate, allowing to form billets, rolls and tubes.
基金the projects financially supported by National Agricultural Science and Technology Achievement Transformation Project(No.2009GB2B200101)2011 Specialized Research Fund for the Doctoral Program of Higher Education(No.20112305120003)+1 种基金2009 Specialized Research Fund for the Doctoral Program of Higher Education(No.20092305110002)Start-up Capital of Doctoral Research of Heilongjiang Bayi Agricultural University(No.2011YB-08).
文摘A new type of rice seedling carrier named seedling-growing bowl tray made of paddy straw(SGBTMPS)was developed in China.Traditional preparation process for SGBTMPS is complex and difficult to operate.Hence,a new SGBTMPS preparation method has been developed by using straw powder as the main raw material.In this method,modified starch-based adhesive was replaced by the binder of thermosetting adhesive,and preparation constraints such as forming pressure,forming temperature,and dwell time were decreased.The effects of factors such as glue(modified starch-based adhesive),forming pressure,forming temperature and dwell time on SGBTMPS preparation were evaluated by single factor experiment.Orthogonal experiment and comprehensive weight analyses were adopted to optimize the parameters for SGBTMPS preparation.The results showed that optimized parameters were 125% glue and 1.2 kg mixed materials with the forming pressure,temperature,and dwell time of 30 MPa,140℃ and 330 seconds,respectively.Compared with traditional preparation process,the proportioning link,preparation link,and preparation time in the new preparation process were reduced by 66.7%,33.3%,and 17%,respectively;the pot-hole percentage and the expansion ratio were increased by 0.09% and 0.05%,respectively.This study indicated that the new preparation process for SGBTMPS was simpler and easier to operate and would provide a useful reference for further research and industrialization on SGBTMPS.
文摘Possibility of making Al-Pb alloy plate with Pb dispersed uniformly by LDC (Liquid Dynamic Compact) technology has been studied in the present paper. The relationship among the distance between nozzle and cooled base plate and the atomization pressure as well as the density of the Al-Pb alloy slab is measured. The relative density of the LDC Al-Pb alloy slab can reach 90% under condition of the present experiment. Microstructure of the slab consist of equal axial grains with 15 approximately 25 μm in diameter and Pb dispersed uniformly in them. After cold or hot rolling of the slab with reduction of 50 approximately 60%, the microstructure can be densified. The rolled Al-Pb alloy plate can be compacted together with pure Al plate very well.
文摘研究了高能球磨对Si粉微观结构和水解制氢性能的影响。球磨过程中,颗粒尺寸不断减小,非晶转变发生,晶界、内应力、位错以及晶格变形等微观缺陷不断增加,有利于提高Si粉的制氢性能;但随着球磨时间的延长,颗粒团聚趋于严重,粉末氧化不断加剧,降低了Si粉的制氢性能。当球磨时间为1 h,Si粉具有最优的制氢性能,70℃水解时其放氢量为1 484.2 m L·g^(-1)Si,但由于水解副产物SiO_2包覆在Si表面导致其转化率为94%,无法继续完全水解。
文摘The epoxy powder exterior anti-corrosion coating production line for bent pipes with a single (double) course production is a technologically advanced bent pipe anti corrosion method with cost efficiency, environment friendliness and stable coating quality. The quality of the coating on the bent pipe fully meets the requirements of the current national and industrial standards. The application of the technology has filled the gap in the bent pipe anti corrosion coating area of China, and leads the world technologically. With this technology the coating quality of the bent pipe has greatly improved, resulting in significant social and economic benefits. With the use of the technology in various large scale pipeline projects such as the "West to East Gas Pipeline Project", it will exhibite a greater potential in the future pipeline projects with a broad application prospect.
基金financial supports from the Scientific and Technological Research Council of Turkey(No.215M895)。
文摘This study was carried out to investigate the possibility of titanium alloy metal powder production using low-power plasma torches.An argon DC non-transferred arc plasma torch was designed,and numerical analysis was conducted to determine the plasma jet properties and wire temperature.The highest velocities inside the nozzle attachment were between 838 and 1178 m/s.The velocities of the jets at the apex were between 494 and 645 m/s for different gas flow rates.The studied plasma gas flow rates had no significant effect on the effective plasma jet length.It was shown that the plasma jet length can be estimated by numerical analysis using the temperature and velocity changes of the plasma jet over distance.It was observed that the powders produced were spherical without any satellites.As a result of this study,a plasma torch was developed and powder production was performed successfully by using relatively low torch power.
基金the Major State Ba-sic Research Development Program of China (Nos. 2006CB605203 and 2006CB605204)
文摘Al-20Sn-1Cu powders were prepared by gas atomization in an argon atmosphere with atomizing pressures of 1.1 and 1.6 MPa. The characteristics of the powders are determined by means of dry sieving, scanning electron microscopy （SEM）, optical microscopy （OM）, and X-ray diffractometry （XRD）. The results show that the powders exhibit a bimodal size distribution and a higher gas pressure results in a broad size distribution. All particles in both cases are spherical or nearly spherical and satellites form on the surface of coarse particles. Dendritic and cellular structures coexist in the particle. With decreasing particle diameter, the secondary dendrite arm spacing （SDAS） decreases and the cooling rate increases. The particles processed under high gas atomization pressure （1.6 MPa） exhibit a lower SDAS value and a higher cooling rate than those of the same size under low gas atomization pressure （1.1 MPa）. The XRD results show that the Sn content increases with decreasing particle size.
