摘要
用Ｘ射线衍射测定点阵常数法研究了在１０６Ｋ／Ｓ的快速凝固条件下，稀土元素在Ａｕ中的亚稳扩展固溶度，Ｃｅ、Ｓｍ、Ｇｄ、Ｄｙ、Ｅｒ、Ｙｂ和Ｙ在Ａｕ中的亚稳扩展固溶度分别为０．３、０．４、１．５、９．０、１３、１３．４和１０ａｔ％。稀土元素的固溶度随它们与金原子半径相对差的减少而明显增大，用稀土与Ａｕ合金化时发生电子从稀土原子向金原子转移来说明稀土在Ａｕ中较大的固溶度。比较和讨论了稀土在Ａｕ、Ａｇ、Ａｌ、Ｃｕ中固溶度亚稳扩展的实验结果，当原子半径相对差小于发生电子转移的临界值时，尺寸因素是控制固溶度的主要因素，尺寸超过临界值后，其它因素变得重要了。发现Ｅｕ和Ｙｂ在与Ａｕ合金化时，与其它稀土元素一样显示三价状态。快速凝固条件下，金－稀土合金的非晶态形成倾向明显高于银－稀土等合金。
Metastable extensive solid solubility of RE metals in gold was studied by measuring the lattice parameters of solid solution of rapidly solidified Au-RE alloys with X-ray diffraction. The cooling rate of the alloys was about 106K/s.It was found that the metastable solid solubilities of Ce,Sm,Gd,Dy,Er,Yb and Y in gold were 0.3,0.4,1.5、9.0,13,13,and 10 at.%respectively.The solid solubilities of RE metals in gold incerased with the decreasing of relative difference of atomic radius between RE metals and gold.The extensive solid solubilities of RE metals in Au,Ag,Al,Cu were compared.The relative larger solid solubility in gold was explained with electron transfer from RE atom to gold atom. When the relative difference of atomic radius was smaller than the critical value(about 25%),the size factor was the main factor that determined the magnitude of solid solubility,and when the relative difference of atomic radius was larger than the critical value,other factors became more important.It was found that Eu and Yb showed trivalent when they alloyed with gold,and under the condition of rapid solidification,the Au-RE alloys more tended to form amorphous alloy strongly than Ag-RE alloys.
出处
《贵金属》
CAS
CSCD
北大核心
1996年第4期1-5,共5页
Precious Metals
关键词
金合金
快速凝固
固溶度
稀土金属
Gold alloy,Rapid solidification,Solid Solubility,Rare-earth metals
