真空荧光显示屏阵列材料氧化过程的研究

Study on Oxidation Process of Array Material Used in Vacuum Fluorescent Display

研究了真空荧光显示屏阵列材料FeNi42Cr6合金在高温湿氢气氛中的氧化行为,其氧化过程为:首先形成Cr2O3,然后(Fe,Mn)Cr2O4氧化物形核、生长,形成完整氧化膜,成熟氧化膜由颗粒状刚玉型氧化物Cr2O3和块状尖晶石型(Fe,Mn)Cr2O4氧化物组成。实验同时表明,阵列板电阻率随氧化膜厚度增加而增大,电阻率过高会导致与之焊接的Ni丝熔断,氧化膜厚度应控制在1μm^2μm。借助扫描电镜、X射线衍射研究了氧化时间、氢气流量、氢气露点等工艺参数对阵列板氧化增重、氧化膜相结构及、氧化膜表面形貌的影响。得出氧化温度为950℃,时间40min^60min,氢气露点(dp)35℃,流量8L/min为最佳阵列材料氧化工艺。

The oxidation process of the VFD array material Fe Ni42Cr6 alloy in wet hydrogen at high temperature has bean researched and the analyses show that, the Cr2O3 film forms on the alloy surface finst, and then (Fe,Mn)Cr2O4 oxide initiates and grow. The mature oxide film consists of two phases, one is (Fe,Mn)Cr2O4 spinel oxide with pin, and the other is Cr2O3 adamantine spar oxide with grain The experimental results also show that the electric-resistivity of array material obviously increase with the thickening of the oxide film yet, Ni thread will get burned when the electric-resistivity is too high. So the thickness of film should be controlled to be less than 2 mum. By the aid of SEM. EDX. and XRD, the effects of temperature, duration, volume and dew point of hydrogen flow during oxidation on weight gain. percentage of the oxide phase., constitution and morphology of oxide scale during oxidation have been studied. Therefore, the optimum processing parameters have been obtained, ie., temperature 950degreesC,duration 40 minsimilar to60 min, dew point and flow rate of hydrogen 35degreesC and 8 L/min respectively.