Mechanism of reaction synthesis of Li-B alloys  

作　　者：刘志坚 曲选辉 李志友 黄伯云 

机构地区：[1]StateKey Laboratoryfor Powder Metallurgy, Central South University [2]College of Materials Science and Engineering, University of Scienceand Technology

出　　处：《Science China(Technological Sciences)》2003年第4期391-400,共10页中国科学（技术科学英文版）

基　　金：This work was supported by the National Natural Science Foundation of China(Grant No.50172062);the EducationMinistry Foundation of China for Excellent Teachers of Colleges.

摘　　要：A model for reaction synthesis of Li-B alloys has been presented. Results show that the first exothermal reaction can be divided into three stages. The first stage is an instantaneous reaction on the boundary between boron particles and lithium melting, in which the caloric released is inversely proportional to the particle size of the boron powder. The second stage is a reaction between the unreacted boron and the lithium that diffuses through the product LiB3 on the surface of the boron particle. This process can be described by Johnston model. The third stage is dissolution of the product LiB3 to Li liquid, which takes place at temperature up to 420℃. At the same time, the second exothermal reaction begins, which consists of nucleation and growth of the last Li-B compound. It can be divided into two substages, i.e. the nucleation pregnant stage and the exploded reaction stage. When the concentration of the particle nucleated is high enough, an exploding reaction takes place. The lower the temperature, the longer the time needed for the exploding reaction. By the model presented, the experimental phenomena in the synthesis are explained.A model for reaction synthesis of Li-B alloys has been presented. Resultsshow that the first exothermal reaction can be divided into three stages. The first stage is aninstantaneous reaction on the boundary between boron particles and lithium melting, in which thecaloric released is inversely proportional to the particle size of the boron powder. The secondstage is a reaction between the unreacted boron and the lithium that diffuses through the productLiB_3 on the surface of the boron particle. This process can be described by Johnston model. Thethird stage is dissolution of the product LiB_3 to Li liquid, which takes place at temperature up to420℃. At the same time, the second exothermal reaction begins, which consists of nucleation andgrowth of the last Li-B compound. It can be divided into two substages, i.e. the nucleation pregnantstage and the exploded reaction stage. When the concentration of the particle nucleated is highenough, an exploding reaction takes place. The lower the temperature, the longer the time needed forthe exploding reaction. By the model presented, the experimental phenomena in the synthesis areexplained.

关 键 词：lithium-boron alloy  REACTION synthesis  THERMAL battery. 

分 类 号：TG146.26[一般工业技术—材料科学与工程]