• 대한화학회지
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• 제9권1호
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• pp.49-54
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• 1965

One of the difficult and time consuming problems in the production of magnesia from sea water is a settling rate of magnesium hydroxide. In this experiments, authors attempted to accelerate its settling rate by addition of various sedimenting agents as C.M.C., Separan and Starch, and sought for optimum calcination temperature for domestic dolomite, as alkali source, mole ratio of dolomite milk to bittern. It is observed through experiments that the small amounts of sedimenting agents, C.M.C., Separan, starch, 20 mg/l, 40 mg/l, 400mg/l, respectively increase the settling rate of magnesium hydroxide by 8 times or more. The following conditions resulted in good yield of magnesium hydroxide from sea water with relatively tolerable calcium oxide contaminated for the magnesium clinker. Calcinating temperature, $1,100{\sim}1,200^{\circ}C$, mole ratio of 10% dolomite milk to magnesium salts in sea water or bittern, 1. 2 : 1.

• Corrosion Science and Technology
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• 제16권3호
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• pp.151-159
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• 2017

The MA8 alloy (formula Mg-Mn-Се) has been shown to have greater corrosion stability than the VMD10 magnesium alloy (formula Mg-Zn-Zr-Y) in chloride-containing solutions by Scanning Vibrating Electrode Technique (SVET) and by optical microscopy, gravimetry, and volumetry. It has been established that the crucial factor for the corrosion activity of these samples is the occurrence of microgalvanic coupling at the sample surface. The peculiarities of the kinetics and mechanism of the corrosion in the local heterogeneous regions of the magnesium alloy surface were investigated by localized electrochemical techniques. The stages of the corrosion process in artificial defects in the coating obtained by plasma electrolytic oxidation (PEO) at the surface of the MA8 magnesium alloy were also studied. The analysis of the experimental data enabled us to determine that the corrosion process in the defect zone develops predominantly at the magnesium/coating interface. Based on the measurements of the corrosion rate of the samples with PEO and composite polymer-containing coatings, the best anticorrosion properties were displayed by the composite polymer-containing coatings.

• 한국결정성장학회지
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• 제13권3호
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• pp.117-121
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• 2003

염화 니켈과 마그네슘 스테아린산 혼합 분말로부터 수소환원 공정에 의하여 니켈 분말을 제조하고 반응온도 및 마그네슘스테아린산의 첨가에 따른 분말의 특성을 검토하였다. 마그네슘 스테아린산을 함유한 경우 과도한 입자 성장의 억제로 인하여 입경 감소 효과가 있었다. 마그네슘 스테아린산의 함유량이 증가함에 따라 이에 따른 액상량의 증가로 인하여 입경 감소와 입자들간의 응집 정도에도 영향을 주었다.

• Journal of Advanced Marine Engineering and Technology
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• 제33권4호
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• pp.517-523
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• 2009

Magnesium alloys have many advantages such as a low density, high strength/weight ratio and well recycle. And joining process is absolutely necessary to expand the field of application of magnesium alloy. The main problems of conventional process such as arc welding for magnesium alloy are the inflammability, a tendency toward crack formation and the appearance of porosity during solidification. Laser welding technology is a promising means for overcoming these difficulties. This study is related to the laser weldability of AZ31 magnesium alloy, an all-purpose wrought alloy with good strength and ductility. The effect of welding conditions on the weldability of butt joints was examined. Also, the mechanical properties of butt welded joints were investigated by tensile test and hardness test.

• Journal of Welding and Joining
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• 제31권3호
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• pp.49-53
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• 2013

Recently, studies about application of magnesium alloy sheet to automotive bodies are on the increase. For application to automotive bodies, researches about characteristics of resistance spot welding of magnesium alloy sheet are essential. Electrode life of resistance spot welding of magnesium alloy is very short due to sticking of magnesium alloy to copper alloy electrode. To increase electrode life, most effective method is inserting cover plate between electrode and magnesium sheet. But application of cover plate to actual process is difficult and decreases welding productivity. Process tape supplied automatically as cover plate can minimize lose of productivity and increase welding quality. In this study, resistance spot welding of magnesium alloy is carried out with applying process tape. Acceptable welding current region according to electrode force and welding time is determined.

• 한국레이저가공학회지
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• 제9권1호
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• pp.25-29
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• 2006

This study aimed to investigate the change of mechanical properties with the rolling direction and shielding condition during laser welding of AZ31 magnesium alloy. AZ31 magnesium alloy sheets of 1mm thickness were welded using a continuous wave Nd:YAG laser with and without Ar shielding gas. The effect of Ar shielding gas and rolling direction on the mechanical properties were investigated using Vickers hardness, transverse-weld tensile. Porosity in the weld metals was investigated using an optical microscope. The experimental results showed that mechanical properties of AZ31 magnesium alloy laser welds were upgraded compared to those of base metal. Mechanical properties of AZ31 magnesium alloy laser welds were not substantially changed when Ar shielding gas was supplied.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2016년도 춘계 학술논문 발표대회
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• pp.141-142
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• 2016

This study was examine the possibility and mechanical properties to adsorption and decrease of caused interior Radon using performance superior cation-exchange to take advantage of the building. Radon absorption type Matrix using the magnesium oxide and vermiculite was experiment to product that vermiculite added Vermiculite to 10% of magnesium oxide and magnesium chloride was fixed to 25%. W/B was carried out in 45, 50, 55, 60 (wt,%).

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2016년도 춘계 학술논문 발표대회
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• pp.26-27
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• 2016

This study is an experiment to know mechanical properties that matrix of the magnesium oxide-based can interior Radon gas absorption and decrease by the addition of Bentonite, Vermiculite, illite having characteristic of the cation-exchange and porous. As a study to examine the possibility was fixed the addition amount of each adsorbent that was added to the 0, 10, 20% of magnesium oxide and magnesium chloride with 25%. Illite, bentonite WB is 45 (wt,%), vermiculite W/B was carried out an experiment to 50 (wt,%).

• 약학회지
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• 제15권1호
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• pp.32-40
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• 1971

Optimum reactons for the preparation of extra-light magnesium carbonate from magnesium chloride and sodium carbonate solutions were found by observing the difference of crystalline shapes under an electromicroscope. Reaction temperature the and washing temperature were main factors affecting the crystalline shapes, and drying temperature was found to be of secondary importance. Optimum temperatures for reaction and washing ranged from $20^{\circ}C$ to $30^{\circ}C$ and the temperature over $40^{\circ}C$ should be avoided for the reaction and washing. It was found that the higher the drying temperature, the lighter the crsytal of the produced magnesium carbonate. Reaction time, molar ratio (Mg$^{2+}/CO_{3}^{2-}$ ) and the concentrations of magnesium chloride and sodium carbonate solutions have only a slight effect on the form of the product.

• 소성∙가공
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• 제21권4호
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• pp.221-227
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• 2012

The automotive and electronic industries have seriously considered the use of magnesium alloys because of their excellent properties such as strength to weight ratio, EMI shielding capability, etc. However, it is difficult to form magnesium alloys at room temperature because of the mechanical deformation related to twinning. Hence, magnesium alloys are normally formed at elevated temperatures. In this study, a temperature dependent constitutive model, the C-H/V model, for the magnesium alloy AZ31B sheet is proposed. A hardening law based on nonlinear kinematic and H/V(Hollomon/Voce) hardening model is used to properly characterize the Bauschinger effect and the stabilization of the flow stress. Material parameters were determined from a series of uni-axial cyclic experiments(C-T-C) with the temperature ranging between 150 and $250^{\circ}C$. The developed models are fit to experimental data and a comparison is made.