Microstructure and Properties of MAO Coatings for AZ91D Magnesium Alloy in Varies Work Mode

2013 ◽  
Vol 747-748 ◽  
pp. 178-183 ◽  
Author(s):  
Xue Jun Cui ◽  
Xiu Zhou Lin ◽  
Chun Hai Liu ◽  
Rui Song Yang ◽  
Ming Tian Li

Micro arc oxidation coatings were prepared on AZ91D magnesium alloy in order to evaluate the role of electrical parameters under different work mode. Taking HV hardness and pit corrosion time as investigation index, the optimum process parameters were obtained through orthogonal experiment method. The morphology of coating was observed by scanning electron microscopy (SEM). The results showed that the coatings with dense and few micro pores can be obtained under constant current and power mode, and this kind coatings are of good corrosion resistance and have HV micro-hardness compared with those under constant voltage mode.

2014 ◽  
Vol 1065-1069 ◽  
pp. 2137-2140
Author(s):  
Xiao Hu Yang ◽  
Yan Long ◽  
Ling Zhao Meng ◽  
Yu Hui Jin

In this paper, we used orthogonal experiment method and Computational Fluid Dynamics (CFD) technology to simulate the thermal environment of the iron and steel workshop. By comparing and analyzing the temperature distribution and air flow of workshops with different window structures, we obtained an optimization of natural ventilation design for industrial workshop. The research results can be used for the structure design or reformation of industrial workshops as reference.


2012 ◽  
Vol 724 ◽  
pp. 159-162
Author(s):  
Yan Chen ◽  
Hong Ping Zhang ◽  
Xiao Yan Lin ◽  
Ming Qi Chen ◽  
Yong Man Jiang

The influences of processing parameters on the tensile strength (TS) of KGM/CaCO3composite films (KCaCF) were investigated through orthogonal experiment method. Calcium carbonate and KCaCF were characterized, respectively, by XRD, laser diffraction particle size analyzer, zeta potential analyzer and SEM. The results showed that micron-sized calcite CaCO3crystals with-16.4 mv of Zeta potential were synthesized. Calcium carbonate dispersion was blended with KGM to fabricate KCaCF. The mass of CaCO3, KGM and swelling time affected TS of composite films differently, but didnt reach the significant level (p>0.05). The optimal preparation process for KCaCF is that 5.0% (wt) of KGM powder is added into the dispersion with 2.0% (wt) of CaCO3, swelling for 1.0 hour at 50 °C and pH 8.0 and then poured onto plate and dried at 50 °C for 15 h.


2012 ◽  
Vol 600 ◽  
pp. 144-147
Author(s):  
Chun Hua Zhao ◽  
Tao Zhao ◽  
Bao Long Hu

Peeling roller is an important working part of multi-function corn peeling machine which can stripping the skin of eaten fresh corn, forage corn and seeding corn. The main material of peeling roller was analysed in this paper, The orthogonal experiment method was used to study the effect of peeling roller’s shape, speed and tilt angle on the corn peeling machine’s performance. The results showed that the material and type of peeling roller has the most significant impact on it. The optimal combination of three factors was A2B3C1: “person shaped” roller-type, 550r/min roller’s speed and 10°peeling angle.


2007 ◽  
Vol 353-358 ◽  
pp. 1645-1648 ◽  
Author(s):  
Dong Chu Chen ◽  
Wen Fang Li ◽  
Jun Jie

A new micro-arc oxidation method with a home-made asymmetric alternating-current (ac) power supply for forming an anti-corrosion ceramic coating on AZ91D magnesium alloy was presented, and two different silicate-based and aluminate-based preparing solutions were introduced to coating formation. The effect of many processing parameters on the growth and performance of the formed ceramic coating was investigated. It was found that the electrolyte concentration, current density, treating time duration and other parameters have significant influence on the coating morphology and anti-corrosion performance. Through the polarization curve test, it showed that the coating oxidized in silicate solution has better corrosion-resistance due to its continuous and compact structure than that formed in aluminate solution. The morphology and microstructure of the coating were analyzed through SEM, XRD technology. The coating consists of two layers, i.e., loose layer and compact layer. The compositions and phase structures varied with electrolytes, and it was found that the micro-arc oxidation coating prepared in silicate solution is composed of MgO and Mg2SiO4, while the coating prepared in aluminate is mainly composed of MgAl2O4.


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