Rare earth and trace elements are determined for cassiterite from a vein-type orebody , a lens and a sheeted-type orebody in the Dachang Sn-polymetallic ore field ,Guangxi Province .Cassiterite from the vein-type oreb...Rare earth and trace elements are determined for cassiterite from a vein-type orebody , a lens and a sheeted-type orebody in the Dachang Sn-polymetallic ore field ,Guangxi Province .Cassiterite from the vein-type orebody has rare earth and trace dement characteristics similar to that of Dachang biotite granite of Late Yanshan age, showing an inheritable and a genetic relationship. Cassiterites from the kns and sheeted-vein orebody have rare earth and trace element characteristics greatly different from those of the vein-type cassiterite and the granite,showing distinctly higher contents of the ore-forming elements As, Sb,Zn,Ag etc.and a positive Eu anomaly and a negative Ce anomaly.The difference of rare earth and trace element characteristics for cassiterite from two kinds of orebodies reflects the compositional difference of ore-forming solutions. Authors suggest that the kns and sheeted-vein orebody was of nonmagmatic , mixed with underground hot brine origin , and that this kind of hot brine reacted with Devonian and Predevonian older strata and extraced some ore-forming metals from the strata and finaly empbced along the bedding and interbyer fracture zone etc. on its ascending way driven by the Indonisian orogenic movement . The vein-type orebody was formed chiefly by post-magmatic hydrothermal sobtions derived from magma differentiation of the Dachang biotite granite .展开更多
In this study,the effect of Tin(Sn)addition on the microstructure,mechanical properties,and wear resistance of pure magnesium(Mg)was examined.Mg-Sn alloys were synthesized using stir casting technique with Sn concentr...In this study,the effect of Tin(Sn)addition on the microstructure,mechanical properties,and wear resistance of pure magnesium(Mg)was examined.Mg-Sn alloys were synthesized using stir casting technique with Sn concentrations of 2.5%,5%,and 7.5% by weight.The specimens were prepared as per ASTM standards for their evaluation.Higher Sn concentrations result in a reduced volume fraction of the eutectic phase,while Mg_(2)Sn precipitates are observed in alloys with 5% or more Sn.Scanning electron microscopy(SEM)analysis of the Mg-7.5wt.%Sn alloy reveals the presence of Mg(OH)_(2),with X-ray diffraction(XRD)confirming an oxygen content of 18% by weight.The addition of Sn minimizes casting porosity,enhancing the quality of the alloys.The findings demonstrate a positive correlation between increasing Sn content and enhanced strength and wear resistance.The Mg-7.5wt.%Sn alloy exhibits significantly enhanced tensile properties attributed to grain refinement and the formation of well-defined grain boundaries compared to alloys with lower Sn additions(2.5% and 5%),although a slight reduction in microhardness is observed.Tribological evaluation indicates reduced wear and friction,suggesting better surface performance.This research underscores the complex interplay between Sn content,microstructural evolution,and the resulting mechanical and tribological performance of Mg-Sn alloys.展开更多
基金The project is supported by Professional Foundation of Geology Carl Duesberg Gesellschaft
文摘Rare earth and trace elements are determined for cassiterite from a vein-type orebody , a lens and a sheeted-type orebody in the Dachang Sn-polymetallic ore field ,Guangxi Province .Cassiterite from the vein-type orebody has rare earth and trace dement characteristics similar to that of Dachang biotite granite of Late Yanshan age, showing an inheritable and a genetic relationship. Cassiterites from the kns and sheeted-vein orebody have rare earth and trace element characteristics greatly different from those of the vein-type cassiterite and the granite,showing distinctly higher contents of the ore-forming elements As, Sb,Zn,Ag etc.and a positive Eu anomaly and a negative Ce anomaly.The difference of rare earth and trace element characteristics for cassiterite from two kinds of orebodies reflects the compositional difference of ore-forming solutions. Authors suggest that the kns and sheeted-vein orebody was of nonmagmatic , mixed with underground hot brine origin , and that this kind of hot brine reacted with Devonian and Predevonian older strata and extraced some ore-forming metals from the strata and finaly empbced along the bedding and interbyer fracture zone etc. on its ascending way driven by the Indonisian orogenic movement . The vein-type orebody was formed chiefly by post-magmatic hydrothermal sobtions derived from magma differentiation of the Dachang biotite granite .
文摘In this study,the effect of Tin(Sn)addition on the microstructure,mechanical properties,and wear resistance of pure magnesium(Mg)was examined.Mg-Sn alloys were synthesized using stir casting technique with Sn concentrations of 2.5%,5%,and 7.5% by weight.The specimens were prepared as per ASTM standards for their evaluation.Higher Sn concentrations result in a reduced volume fraction of the eutectic phase,while Mg_(2)Sn precipitates are observed in alloys with 5% or more Sn.Scanning electron microscopy(SEM)analysis of the Mg-7.5wt.%Sn alloy reveals the presence of Mg(OH)_(2),with X-ray diffraction(XRD)confirming an oxygen content of 18% by weight.The addition of Sn minimizes casting porosity,enhancing the quality of the alloys.The findings demonstrate a positive correlation between increasing Sn content and enhanced strength and wear resistance.The Mg-7.5wt.%Sn alloy exhibits significantly enhanced tensile properties attributed to grain refinement and the formation of well-defined grain boundaries compared to alloys with lower Sn additions(2.5% and 5%),although a slight reduction in microhardness is observed.Tribological evaluation indicates reduced wear and friction,suggesting better surface performance.This research underscores the complex interplay between Sn content,microstructural evolution,and the resulting mechanical and tribological performance of Mg-Sn alloys.
