en گروه سرامیک Ceramic Materials and Engineering Research Paper Research Paper <span style="font-size:11pt"><span style="line-height:13.0pt"><span style="layout-grid-mode:char"><span style="unicode-bidi:embed"><span style="font-family:Calibri,sans-serif"><span style="font-size:9.0pt"><span linotype="" palatino="" style="font-family:"><span style="color:black">The present work deals with the</span></span></span><span style="font-size:9.0pt"><span linotype="" palatino="" style="font-family:"><span style="color:black"> corrosion behavior and mechanical properties of a coted AZ31 magnesium alloy through plasma electrolyte oxidation (PEO) coating process in different alkaline electrolytes based on sodium silicate (Si-coating), sodium polyphosphate (P-coating) and sodium aluminate (Al-coating). The scanning electron microscopy (SEM) equipped with the energy dispersive x-ray spectroscopy (EDX) plus x-ray diffraction were recruited to investigate the morphology, chemical composition, and phase structure of coatings, respectively. Microscopic scrutiny revealed that the coating in the phosphate electrolyte was twice as thick and the relative porosity percentage was higher than those formed in the other electrolytes. The phase analysis indicated that the MgO was present as the prevailing phase in the Al-coating and P-coating. However, the dominant phase in the Si-coating was Mg₂SiO₄. Electrochemical testing was examined in a solution containing 3.5.wt% sodium chloride, showing improvements in corrosion resistance of coated alloys. These investigations confirmed that the corrosion resistance of Si-coating was dramatically higher than others which could be attributed to the presence of the dense and stable Mg₂SiO₄ phase as well as its relatively low porosity. According to the results of tensile tests, the coated samples had lower tensile strength and elongation than the uncoated one. The tensile strength and elongation </span></span></span><span style="font-size:9.0pt"><span linotype="" palatino="" style="font-family:"><span style="color:black">diminished upon</span></span></span><span style="font-size:9.0pt"><span linotype="" palatino="" style="font-family:"><span style="color:black"> changing the electrolyte from Al-coating to P-coating, while the yield strength was almost similar. Further analyses </span></span></span><span style="font-size:9.0pt"><span linotype="" palatino="" style="font-family:"><span style="color:black">indicated</span></span></span><span style="font-size:9.0pt"><span linotype="" palatino="" style="font-family:"><span style="color:black"> that the drop of tensile strength and elongation could be attributed to the presence of cracks and pores in the brittle ceramic PEO coating as stress concentration regions during deformation. Those areas are created due to thermal stress during the coating process and deformation in the elastic stage.</span></span></span><span dir="RTL" new="" roman="" style="font-family:" times=""><span style="color:black"></span></span></span></span></span></span></span><br> &nbsp; Mechanical properties,AZ31 Magnesium alloy,plasma electrolytic oxidation (PEO),corrosion behavior 86 100 http://ijmse.iust.ac.ir/browse.php?a_code=A-10-167-10&slc_lang=en&sid=1 Yasin Mehdizadeh yas.mehdizade@ut.ac.ir 1800319475328460021777 1800319475328460021777 No School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran Saeed Reza allahkaram akaram@ut.ac.ir 1800319475328460021778 1800319475328460021778 Yes School of Metallurgy and Materials Eng., College of Eng., University of Tehran Mohammad H.Mohammad-Ebrahimi mohammadebrahimi.ut@gmail.com 1800319475328460021779 1800319475328460021779 No School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran Majid Shamsarjmand madjidshams@ae.sharif.edu 1800319475328460021780 1800319475328460021780 No Department of Aerospace Engineering, Sharif University of Technology, Tehran, Iran