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张圣麟 《中国稀土学报(英文版)》2009,27(3):469-473
Zinc phosphate coatings formed on 6061-Al alloy, after dipping in phosphating solutions containing different amounts of Y2O3(yttrium oxide), were studied by scanning electron microscopy (SEM), X-ray diffraction (XRD) and electrochemical measurements. Significant variations in the morphology and corrosion resistance afforded by zinc phosphate coating were especially observed as Y2O3 in phosphating solution varied from 0 to 40 mg/L. The addition of Y2O3 changed the initial potential of the interface between aluminum alloy substrate and phosphating solution and increased the number of nucleation sites. The phosphate coating thereby was less porous structure and covered the surface of aluminum alloy completely within short phosphating time. Phosphate coating was mainly composed of Zn3(PO4)2-4H2O (hopeite) and AIPO4(aluminum phosphate). Y2O3, as an additive of phosphatization, accelerated precipitation and refined the gain size of phosphate coating. The corrosion resistance of zinc phosphate coating in 3% NaCl solution was improved as shown by po-larization measurement. In the present research, the optimal amount of Y2O3 was 10-20 mg/L, and the optimal phosphating time was 600 s. 相似文献
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以煤油—水—丁酸为体系,通过实验,研究了HL—20型离心萃取器的水力学及传质性能。一、概述圆筒式离心萃取器是60年代后期发展起来的一种离心萃取设备,与其它离心萃取器相比,圆筒式离心萃取器有其自己的特点,即结构简单,适应性强。在离心萃取器的加工中,技术要求最严格的是转鼓。不同规格的转鼓,生产能力可以从每小时几升到100m3/h,且其转鼓是上悬的,浸在液体部分的转动件没有密封的问题,消除了液体的漏液。在圆筒式离心萃取器中由于 相似文献
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涂装预处理除油工艺的正确选择与使用 总被引:3,自引:0,他引:3
除油是金属表面处理最常见的工序,本文论述并比较了目前在除油工艺中一些常见的清洗方法,提出了选择清洗剂的原则和应注意的问题。 相似文献