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为了提高Bi-2212/Ag带的性能(主要指临界电流密度Jc),进行了部分熔化热处理工艺对带材Jc的实验。采用标准的4点法测量Jc,使用PW1700 XRD、SL20 SEM和EDX检验和研究带材的相组成和微观组织。实验表明:在流氧气氛下,烧结温度为860℃~880℃时,前驱粉末以Bi-2212为主相,同时含有少量的Bi-2201相、(Sr,Ca)Cu2O3相和富(Bi,Sr)相。在流氧气氛下,带材Jc性能对热处理工艺参数非常敏感。在实验条件范围内,优化后的热处理工艺参数为:熔化温度Tmax=890℃,熔化时间tmax=10 min,冷却速率Rc=2℃h-1;在保温温度为835℃时,保温时间ta=20 h,通过优化的部分熔化热处理工艺,在77 K、0 T下最后所制得带材的最大Ic=6 A,Jc=890 Acm-2。
In order to improve the performance of the Bi-2212 / Ag tape (mainly referred to as the critical current density Jc), the experiment of the partial melting heat treatment on the strip Jc was carried out. Jc was measured using a standard 4-point method, and the phase composition and microstructure of the tape were examined and studied using PW1700 XRD, SL20 SEM and EDX. The results show that when the sintering temperature is in the range of 860 ℃ to 880 ℃, the precursor powder mainly contains Bi-2212 and a small amount of Bi-2201 phase, (Sr, Ca) Cu2O3 phase and Bi- Sr) phase. In a flowing oxygen atmosphere, the strip Jc properties are very sensitive to the heat treatment process parameters. Under the experimental conditions, the optimized heat treatment process parameters are as follows: melting temperature Tmax = 890 ℃, melting time tmax = 10 min, cooling rate Rc = 2 ℃ h-1; when the temperature is 835 ℃, 20 h, the maximum Ic = 6 A, Jc = 890 Acm-2 of the final strip obtained at 77 K, 0 T by the optimized partial melting heat treatment process.