作　　者： ; ; ; ;

机构地区： 天津大学理学院物理系

出　　处： 《Chinese Journal of Chemical Physics》 2004年第4期471-475,共5页

摘　　要： 采用均匀颗粒成型法 (UniformDropletSpray ,UDS)在氮气氛下 (氧含量为 1.3 6μmol/L)制备了 15 0和 185μmSn 5 %Pb合金颗粒 .采用光学显微镜观测颗粒的外观形貌 ,结果表明 ,UDS方法制备的微粒是粒度均匀的球状颗粒 ;利用非绝热容量法确定了颗粒的形核点及过冷度 ;计算了以时间和温度为函数的颗粒表面被氧化的比例 ,提出了以颗粒表面氧化为催化媒质的异质成核理论模型 ,合理反映了颗粒的异质成核过程 .在此基础上计算了微粒表面异质形核条件下的连续冷却转变 (ContinuousCoolingTransformation ,CCT)曲线 ,同时以线性冷却条件为例预测了颗粒的冷却凝固行为 . The Sn 5%Pb droplets with sizes of 150 and 185 μm were generated by Uniform Droplet Spray (UDS) under N 2 atmosphere with 1.36 μmol/L oxygen. The appearance of Sn 5%Pb droplets under the optical microscope showed that the droplets are uniform and spherical. The method employed non adiabatic calorimetry to determine the nucleation point and undercooling of droplets. The fraction covered by oxide was calculated as a function of time and temperature. The model for heterogeneous nucleation catalyzed by oxidation on the droplet surface was developed, which was a reasonable expression of the heterogeneous nucleation and solidification behavior of Sn Pb droplets. The CCT curves were computed using above experimental results under the heterogeneous surface nucleation of droplet. The same model can be applied to predict the heterogeneous nucleation behavior of the droplets for any type of cooling schedule. The calculation results are very reliable based on the experimental data.

关 键 词： 锡 铅合金颗粒 异质成核 均匀颗粒成型法 过冷度 冷却凝固行为 连续冷却转变曲线

领　　域： [冶金工程] [冶金工程]