The main technical problems of nickel powder for multiplayer ceramic capacitors are particle size controlling, the agglomeration and tap density. Ultrafine nickel powders with submicron size and spherical shape were s...The main technical problems of nickel powder for multiplayer ceramic capacitors are particle size controlling, the agglomeration and tap density. Ultrafine nickel powders with submicron size and spherical shape were synthesized by the hydrazine reduction of nickel sulfate in ethanol-water solvent. The effects of reaction temperature, nucleator and flow rate of nickel sulfate solution on nickel powders properties were investigated. The nickel particles synthesized were characterized by SEM and TGA. The results show that the average particle size changes from 0.1 to 0.7 μm by adjusting reaction temperature (53- 73 ℃) and flow rate of nickel sulfate solution (50- 100 mL/min). Moreover, temperature below 60 ℃ and appropriate flow rate of nickel sulfate solution (85 mL/min) are in favor of obtaining particles with high tap density (>3.0 g/cm3). In addition, the introduction of nucleator is useful to obtaining particles with narrow size distribution.展开更多
1 INTRODUCTIONIt is estimated that there are about 6000 tons of arsenic loaded into smelters along with theirvarious concentrates each year in China(reference data from 1986).As result,a lot of flue dustcontaning arse...1 INTRODUCTIONIt is estimated that there are about 6000 tons of arsenic loaded into smelters along with theirvarious concentrates each year in China(reference data from 1986).As result,a lot of flue dustcontaning arsenic and antimony is produced.Utilization and treatment of this flue dust are ofsignificance for the econony of recovery of arsenic and antimony and the environmental protection.But conventional treatment processes of Pyrometallurgical volatilization and hydrometallurgicalleaching are unsatisfactory because of the difficulty in seperating As and Sb as well as inpreventing secondary pollution.This research is intended to develop a new low temperaturechlorination-distillation process with high recovery of val uables and low pollution.展开更多
Barium (Bag) ferrite ultra fine powders were synthesized by using sol-gel in which polyethylene glycol 200(PEG200) was used as gelling agent. The transition of Ba ferrite was studied by thermal gravimetric and differe...Barium (Bag) ferrite ultra fine powders were synthesized by using sol-gel in which polyethylene glycol 200(PEG200) was used as gelling agent. The transition of Ba ferrite was studied by thermal gravimetric and differential thermal analysis (TG-DTA) technology. The micro structural changes were analyzed using X-ray diffraction (XRD) and atomic force microscopy (AFM) for the specimens annealed at different temperatures. The transition temperatures were 414.55°C and separately corresponding to BaFe2O4 and BaFe,2O19. There were three types of microstructures for Ba ferrite ultrafine powder specimen annealed at 800°C. For the specimens annealed at different temperatures, there were different kinds of Ba ferrites. The ferrite powder consists of BaFet2O19 and BaFe2O4 for the specimen annealed at 800°C, and only BaFe^O^ can be found in the specimen annealed at 1000°C. The magnetic properties, a , and H c of BaFC|2O19 ultrafine powders are different from that of BaFe12O19 bulk material.展开更多
基金Project(50474047) supported by the National Natural Science Foundation of China
文摘The main technical problems of nickel powder for multiplayer ceramic capacitors are particle size controlling, the agglomeration and tap density. Ultrafine nickel powders with submicron size and spherical shape were synthesized by the hydrazine reduction of nickel sulfate in ethanol-water solvent. The effects of reaction temperature, nucleator and flow rate of nickel sulfate solution on nickel powders properties were investigated. The nickel particles synthesized were characterized by SEM and TGA. The results show that the average particle size changes from 0.1 to 0.7 μm by adjusting reaction temperature (53- 73 ℃) and flow rate of nickel sulfate solution (50- 100 mL/min). Moreover, temperature below 60 ℃ and appropriate flow rate of nickel sulfate solution (85 mL/min) are in favor of obtaining particles with high tap density (>3.0 g/cm3). In addition, the introduction of nucleator is useful to obtaining particles with narrow size distribution.
文摘1 INTRODUCTIONIt is estimated that there are about 6000 tons of arsenic loaded into smelters along with theirvarious concentrates each year in China(reference data from 1986).As result,a lot of flue dustcontaning arsenic and antimony is produced.Utilization and treatment of this flue dust are ofsignificance for the econony of recovery of arsenic and antimony and the environmental protection.But conventional treatment processes of Pyrometallurgical volatilization and hydrometallurgicalleaching are unsatisfactory because of the difficulty in seperating As and Sb as well as inpreventing secondary pollution.This research is intended to develop a new low temperaturechlorination-distillation process with high recovery of val uables and low pollution.
文摘Barium (Bag) ferrite ultra fine powders were synthesized by using sol-gel in which polyethylene glycol 200(PEG200) was used as gelling agent. The transition of Ba ferrite was studied by thermal gravimetric and differential thermal analysis (TG-DTA) technology. The micro structural changes were analyzed using X-ray diffraction (XRD) and atomic force microscopy (AFM) for the specimens annealed at different temperatures. The transition temperatures were 414.55°C and separately corresponding to BaFe2O4 and BaFe,2O19. There were three types of microstructures for Ba ferrite ultrafine powder specimen annealed at 800°C. For the specimens annealed at different temperatures, there were different kinds of Ba ferrites. The ferrite powder consists of BaFet2O19 and BaFe2O4 for the specimen annealed at 800°C, and only BaFe^O^ can be found in the specimen annealed at 1000°C. The magnetic properties, a , and H c of BaFC|2O19 ultrafine powders are different from that of BaFe12O19 bulk material.
