Sealing Treatment of Aluminum Coating on S235 Steel with Thermal Diffusion of Zinc
Sealing Treatment of Aluminum Coating on S235 Steel with Thermal Diffusion of Zinc
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DOI：
10.1007/s11666-015-0277-4
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发表时间：
2015-07
影响因子：
3.1
通讯作者：
Yong Wang;Timing Zhang;Weiming Zhao;Xiuyan Tang
中科院分区：
文献类型：
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作者：
Yong Wang;Timing Zhang;Weiming Zhao;Xiuyan Tang
研究了S235碳钢表面电弧喷涂铝涂层的热扩散封闭处理。将喷涂的铝-锌双涂层加热到420 °C，使得低熔点锌可以扩散到铝涂层的孔隙中。采用光学显微镜、显微硬度、电子探针显微分析和X射线衍射对封接处理进行了评价。计算出锌在电弧喷涂铝涂层中的扩散系数约为7.735 × 10− 9 cm 2/s。渗锌可提高铝镀层的致密度和显微硬度。然而，如果锌与钢基体接触，不利的界面反应会破坏涂层。FeZn 10可以先形成，然后锌和铁之间的放热反应产生的热量会引发铁，铝和锌之间的反应。FeAl-Znx、FeAl 2-Znx和Fe 2Al 5-Znx在FeZn 10之后生成。缺陷组织主要由Fe 2Al 5-Znx和FeZn 10组成。所有这些都形成了对涂层性能具有负面影响的坚韧、易碎的金属间化合物。因此，应避免锌与钢基体接触，并将保温时间限制在8.16 × 106 L2，以防止金属间化合物的生成。
The study introduced a thermal diffusion sealing treatment for arc-sprayed aluminum coating on S235 carbon steel. The sprayed aluminum-zinc duplex coating was heated to 420 °C, so that the low-melting-point zinc could diffuse into the pores of the aluminum coating. Optical microscope, microhardness, electron probe microanalysis, and x-ray diffraction were used to evaluate the sealing treatment. The calculated diffusion coefficient for zinc in the arc-sprayed aluminum coating was approximately 7.735 × 10−9cm2/s. The diffused zinc could increase the compactness and microhardness of the aluminum coating. Nevertheless, adverse interface reactions could destroy the coating if the zinc made contact with the steel substrate. FeZn10could form initially, and then the heat from the exothermic reactions between zinc and iron would initiate the reactions among iron, aluminum, and zinc. FeAl-Znx, FeAl2-Znx, and Fe2Al5-Znxwere generated following FeZn10. The defected structures were mainly composed of Fe2Al5-Znxand FeZn10. All of these formed tough, brittle, intermetallics that have a negative effect on the coating performance. Thus, the contact between zinc and the steel substrate should be avoided, and the holding time should be restricted to 8.16 × 106L2to prevent the generation of intermetallics.