Relative contact angle and heat of wetting can be used to provide a measurement of surface wettability of synthetic magnetite. The comparison between synthetic and natural magnetite in terms of surface wettability sho...Relative contact angle and heat of wetting can be used to provide a measurement of surface wettability of synthetic magnetite. The comparison between synthetic and natural magnetite in terms of surface wettability showed that, using the same kind of wetting liquid, the difference in the relative contact angle was 10° between the concentrate and tailings obtained from reverse fl otation of synthetic magnetite, while the difference was more than 20° between the concentrate and tailings obtained from reverse fl otation of natural magnetite. As for the concentrate and tailings from reverse fl otation of synthetic magnetite with water as wetting liquid, the relative ratio of their wetting heat was 106.21%. In comparison, the relative ratio of wetting heat was 176.59% for concentrate and tailings from reverse fl otation of natural magnetite, showing a 70.38% difference.展开更多
The surface tensions and contact angles of Fe_(78)Si_9B_(13) and Fe_(73.5)Cu_1Nb_3Si_(13.5)B_9 alloy melts were studied as a function of temperature in various atmospheres(vacuum, Ar and N_2 gas) and on different subs...The surface tensions and contact angles of Fe_(78)Si_9B_(13) and Fe_(73.5)Cu_1Nb_3Si_(13.5)B_9 alloy melts were studied as a function of temperature in various atmospheres(vacuum, Ar and N_2 gas) and on different substrates(Si C, Al_2O_3 and BN). It is indicated that Si_3N_4, NbN, Fe_2 Al B and B_(13)C_2 are generated as new phases at the interface between the melt and substrate, and reactive wetting behaviour exists during the heating process. The surface tensions of two alloy melts on BN substrate both firstly decrease and then increase along with increasing temperature, leading to V-shaped surface tension versus temperature, which results from atomic diffusion effects in the surface layer during the oxidation of BN and formation of C-rich layer. Comparably, the surface tensions on Al_2O_3 and Si C substrates decrease with increasing temperature throughout the entire temperature range. Among three substrates, BN exhibits the mildest wetting behaviour. The vacuum environment has the strongest protective effect on melt stability among the tested atmospheres. These findings enrich our knowledge about the effects of the substrate and atmosphere on Fe-based alloy melts at a high temperature, and provide theoretical reference for designing jet nozzles in melt-spinning techniques.展开更多
基金Funded by the National Natural Science Foundation of China(No.51144003)
文摘Relative contact angle and heat of wetting can be used to provide a measurement of surface wettability of synthetic magnetite. The comparison between synthetic and natural magnetite in terms of surface wettability showed that, using the same kind of wetting liquid, the difference in the relative contact angle was 10° between the concentrate and tailings obtained from reverse fl otation of synthetic magnetite, while the difference was more than 20° between the concentrate and tailings obtained from reverse fl otation of natural magnetite. As for the concentrate and tailings from reverse fl otation of synthetic magnetite with water as wetting liquid, the relative ratio of their wetting heat was 106.21%. In comparison, the relative ratio of wetting heat was 176.59% for concentrate and tailings from reverse fl otation of natural magnetite, showing a 70.38% difference.
基金supported by the National Natural Science Foundation of China(Grant No.51501043)National Scientific and Technological Support Projects(Grant No.2013BAE08B00)+1 种基金National Key Scientific Instrument and Equiment Development Project(Grant No.2014YQ120351)Science and Technology Program of Beijing(Grant No.Z141100003814007)
文摘The surface tensions and contact angles of Fe_(78)Si_9B_(13) and Fe_(73.5)Cu_1Nb_3Si_(13.5)B_9 alloy melts were studied as a function of temperature in various atmospheres(vacuum, Ar and N_2 gas) and on different substrates(Si C, Al_2O_3 and BN). It is indicated that Si_3N_4, NbN, Fe_2 Al B and B_(13)C_2 are generated as new phases at the interface between the melt and substrate, and reactive wetting behaviour exists during the heating process. The surface tensions of two alloy melts on BN substrate both firstly decrease and then increase along with increasing temperature, leading to V-shaped surface tension versus temperature, which results from atomic diffusion effects in the surface layer during the oxidation of BN and formation of C-rich layer. Comparably, the surface tensions on Al_2O_3 and Si C substrates decrease with increasing temperature throughout the entire temperature range. Among three substrates, BN exhibits the mildest wetting behaviour. The vacuum environment has the strongest protective effect on melt stability among the tested atmospheres. These findings enrich our knowledge about the effects of the substrate and atmosphere on Fe-based alloy melts at a high temperature, and provide theoretical reference for designing jet nozzles in melt-spinning techniques.
