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The oxidation of two two-phase ternary Fe-Cu-Al alloys containing about 5%(mole fraction) aluminium, one Fe-rich and one Cu-rich, has been studied at 900 ℃ in 1~105 Pa pure oxygen. The Fe-rich Fe-15Cu-5Al alloy presents two quasi-parabolic stages, with a large decrease of the parabolic rate constant after about 50min. The presence of 5% Al greatly reduces the oxidation rate of this alloy with respect to a binary Fe-Cu alloy of similar composition by forming an external protective Al203 layer, which is present near the scale/alloy interface. Due to the high stress-growth effect, this thin Al203 layer cannot completely prevent further oxidation of the alloy underneath. On the contrary, the Cu-rich Fe-85Cu-5Al alloy presents a single parabolic stage and forms a thick and porous external scale, coupled to the internal oxidation of Fe and Al. As a result, the oxidation of Cu-rich alloy at 900 ℃ is much faster than that of the Fe-rich alloy. 相似文献
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戊二酸二异辛酯的杂多酸催化合成及应用研究 总被引:2,自引:0,他引:2
以从二羧酸中分离出的戊二酸和异辛醇为原料 ,在杂多酸催化作用下酯化合成了戊二酸二异辛酯。考察了醇酸物质的量比、反应温度、反应时间、催化剂及用量等因素对酯化反应的影响 ,确定了较佳的工艺条件 :醇酸量比 2 5∶1 0 ,反应温度 14 0℃ ,反应时间 12 0min ,催化剂用量为体系总质量的 0 2 % ,在此条件下 ,酯化率可达 99%以上。测试了产品的IR、1HNMR和密度、黏度、折光率等一些性能指标 ,并做了PVC电缆外护套的应用试验 相似文献
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蜜饯的快速渗糖新工艺 总被引:1,自引:0,他引:1
报道一种在动态条件下,经三次渗糖的快速渗糖新工艺,可将原工艺的渗糖时间缩短20h,并实现日加工鲜果1t的生产规模。 相似文献
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