IMPROVEMENT OF AN EPOXY COATING ADHESON BY FORMING AN ANODIZED AL OXDE (AAO). THIN LAYER CONTAINING NANO PORES ON AL SUBSTRATE

سال انتشار: 1390
نوع سند: مقاله کنفرانسی
زبان: انگلیسی
مشاهده: 330

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شناسه ملی سند علمی:

UFGNSM03_056

تاریخ نمایه سازی: 10 تیر 1396

چکیده مقاله:

To enhance the corrosion resistance, polymeric coatings of aluminium substrates are widely used in aerospace and automotive industries. A thin layer of an anodized aluminium oxide (AAO), containing nano-size pores on Al substrate leads to a strong polymer/metal bond, due to penetration of polymer into the nano-sized pores and development of a strong mechanical interlocking. In this study, a 7075 aluminium alloy was anodized in two steps: (i) Initial anodizing which produced an anodized layer with irregular pores morphology, followed by removing the Al2O3 layer using H3PO4 and CrO3. (ii) Second anodizing which modified the morphology and uniformity of pores. The effects of the anodizing conditions (anodizing time and electrolyte temperature) on the AAO morphology were studied. AAO morphology and topography were investigated by using FE-SEM and AFM micrographs, respectively. Adhesion strength was evaluated by using pull-off method. Anodizing at 20 °C resulted in a porous layer with average pore diameters of about 80 nm and the cell wall thickness of about 30 nm. By increasing the electrolyte temperature to 40 °C, AAO changed to a whisker-like structure, which included protrusions with 60 nm diameter. Both, wet and dry adhesion strength increased considerably by anodizing in phosphoric acid as a pretreatment which grantees bond performance and also durability duringSSW(S

نویسندگان

ALI HATEFI

Department of Materials Engineering, Faculty of Mechanical Engineering, University of Tabriz, Tabriz, ۵۱۶۶-۱۶۴۷۱ Iran

SAMIRA MOHLAGHEGHI

Department of Materials Engineering, Faculty of Engineering, Islamic Azad university, South Tehran Branch Tehran, Iran

ABBAS KIANVASH

Department of Materials Engineering, Faculty of Mechanical Engineering, University of Tabriz, Tabriz, ۵ I ۶۶-۶۴۷ i Iran