It is known to all that China is abundant in rare earth resources. But rare earth deposits are really not that rare in the earth crest. In the five continents, i.e. Asia, Europe, Australia, North and South America, an...It is known to all that China is abundant in rare earth resources. But rare earth deposits are really not that rare in the earth crest. In the five continents, i.e. Asia, Europe, Australia, North and South America, and Africa, there are about thirty four countries found to have rare earth deposits; Brazil might surpass China and rank the first in rare earth deposits. At present, investment in rare earth production was surged, there have been about 200 projects, and the total production for 25 of them would be more than 170 thousand tons after 2015, a multi-supply system on rare earths is being established worldwide. Cautions on the investment of rare earth production are involved.展开更多
建立了微波消解-电感耦合等离子体质谱(ICP-MS)测定地质样品中稀土元素的方法,采用HNO3-HF体系-微波消解进行样品前处理,经赶酸后再用5 m L 1∶1 HNO3提取,整个过程安全、高效、无损失。利用ICP-MS进行测定,可以有效降低多原子离子质谱...建立了微波消解-电感耦合等离子体质谱(ICP-MS)测定地质样品中稀土元素的方法,采用HNO3-HF体系-微波消解进行样品前处理,经赶酸后再用5 m L 1∶1 HNO3提取,整个过程安全、高效、无损失。利用ICP-MS进行测定,可以有效降低多原子离子质谱干扰,在优化仪器参数后,用内标铑(Rh)进行校正,弥补基体抑制效应和灵敏度漂移,测试结果更加准确。方法用于岩石标准物质(GBW07109,GBW07110和GBW07111)测试,其测定值与标准值相一致。结果表明,该方法的检出限低,准确度高,操作简单快捷,可同时测定多种元素,能满足批量测定地质样品中稀土元素含量的要求。展开更多
Laser cladding is a promising photon-based surface engineering technique broadly utilized for fabricating harder and wear resistant composite coatings. In spite of excellent properties, the practical applications of l...Laser cladding is a promising photon-based surface engineering technique broadly utilized for fabricating harder and wear resistant composite coatings. In spite of excellent properties, the practical applications of laser claddings are relatively restricted when compared with well-established coating techniques because of their inherent defects identified as cracks, pores and inclusions. Substantial evidence suggests that the incorporation of an appropriate amount of rare earth in laser claddings can remarkably prevent these defects. Additionally, the presence of rare earth in laser claddings can notably enhance tribo-mechanical properties such as surface hardness, modulus of elasticity, fracture toughness, friction coefficient and wear rate. In this literature review, the effect of rare earth in reducing dilution and cracks susceptibility of laser claddings in addition to microstructural refinement attained was examined. Mechanical and tribological properties of these claddings along with their underlying mechanism were discussed in detail. Finally, this article summarizes current applications of laser claddings based on rare earth and was concluded with future research directions.展开更多
文摘It is known to all that China is abundant in rare earth resources. But rare earth deposits are really not that rare in the earth crest. In the five continents, i.e. Asia, Europe, Australia, North and South America, and Africa, there are about thirty four countries found to have rare earth deposits; Brazil might surpass China and rank the first in rare earth deposits. At present, investment in rare earth production was surged, there have been about 200 projects, and the total production for 25 of them would be more than 170 thousand tons after 2015, a multi-supply system on rare earths is being established worldwide. Cautions on the investment of rare earth production are involved.
文摘建立了微波消解-电感耦合等离子体质谱(ICP-MS)测定地质样品中稀土元素的方法,采用HNO3-HF体系-微波消解进行样品前处理,经赶酸后再用5 m L 1∶1 HNO3提取,整个过程安全、高效、无损失。利用ICP-MS进行测定,可以有效降低多原子离子质谱干扰,在优化仪器参数后,用内标铑(Rh)进行校正,弥补基体抑制效应和灵敏度漂移,测试结果更加准确。方法用于岩石标准物质(GBW07109,GBW07110和GBW07111)测试,其测定值与标准值相一致。结果表明,该方法的检出限低,准确度高,操作简单快捷,可同时测定多种元素,能满足批量测定地质样品中稀土元素含量的要求。
基金Project supported by the University of Malaya Research Grant(UMRG,RP013A-13AET)University of Malaya Research Grant(UMRG,RP035A-15AET)
文摘Laser cladding is a promising photon-based surface engineering technique broadly utilized for fabricating harder and wear resistant composite coatings. In spite of excellent properties, the practical applications of laser claddings are relatively restricted when compared with well-established coating techniques because of their inherent defects identified as cracks, pores and inclusions. Substantial evidence suggests that the incorporation of an appropriate amount of rare earth in laser claddings can remarkably prevent these defects. Additionally, the presence of rare earth in laser claddings can notably enhance tribo-mechanical properties such as surface hardness, modulus of elasticity, fracture toughness, friction coefficient and wear rate. In this literature review, the effect of rare earth in reducing dilution and cracks susceptibility of laser claddings in addition to microstructural refinement attained was examined. Mechanical and tribological properties of these claddings along with their underlying mechanism were discussed in detail. Finally, this article summarizes current applications of laser claddings based on rare earth and was concluded with future research directions.
