• Korean Journal of Materials Research
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• v.11 no.11
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• pp.953-959
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• 2001

Homogeneous spherical W-Co salt powders were made by spray drying of aqueous solution of ammonium $metatungstate(NH_4)_6(H_2W_{12}O_{40}){\cdot}4H_2O,\; AMT)$ and cobalt nitrate $hexahydrate(Co(NO_3)_2{\cdot}6H_2O)$. The thermal decomposition process of spray dried W-Co salt powders was studied by TG, XRD, SEM, TEM and FT-IR. Spray dried W-Co salt powders were calcined for 1 hour in the temperature from$ 350^{\circ}C$ to $800^{\circ}C$ in atmosphere of air. At the temperatures over $600^{\circ}C$, spherical $CoWO_4/WO_3$ composite oxide powders were obtained. The primary particle size of W/Co composite oxide powders increased with increasing thermal decomposition temperature due to the particle growth. The observed crystallite size by TEM was in the range of 60nm and that of $CoWO_4$ calculated by Scherrer's formula at $800^{\circ}C$ was smaller than 55nm. The crystallite site was identified by XRD and TEM.

• Journal of Korea Foundry Society
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• v.34 no.2
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• pp.60-66
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• 2014

A Zr-based amorphous alloy specimen was produced by vacuum die casting process. The salt spray test was carried out using the specimens in the as-cast, $Al_2O_3$ and $ZrO_2$ particle blasted state. Using these specimens, the SEM-EDX and XRD analyses, DSC measurement and bending strength test were conducted. After the salt spray test, the specimens were not experienced phase change and thermal characteristics of the alloys were remained unchanged. In the as-cast specimen, corrosion products were not observed. However, in the $Al_2O_3$ particle blasted specimen, pitting corrosion occurred and the detected corrosion products were $ZrCl_2$ and $NaZrO_3$. Due to the salt spray test, bending strength of the $Al_2O_3$ blasted specimens showed about 100 MPa lower strength than the other specimens. The bending fracture surface was vein pattern which was shown typically in the amorphous alloys.

• Transactions of Materials Processing
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• v.21 no.5
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• pp.330-335
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• 2012

Roll formed steel bolts are electrodeposited with Zn-Ni to protect themselves from corrosion. However, white storage stain or white rust(corrosion) is found on Zn-Ni electrodeposited surface of steel bolts when they are exposed to moisture. In this paper a new process is introduced to protect Zn-Ni electrodeposited steel bolt from white storage stain or white rust for a long time under the salt spray test and high humidity test conditions. The better corrosion resistance could be gotten by the additional process of Ni-P electroless deposition and heat treatment to conventional manufacturing method of Zn-Ni coated steel bolt. The corrosion resistance of Zn-Al powder slurry coated steel bolt showed better than that of Zn-Ni electrodeposited one.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.11a
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• pp.221-224
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• 1997

In this study we investigated the acting characteristics of Polymers for electrical insulation by UV radiation and salt water spray treatment. We used the Polymers such as EPDM, SR. PTFE. EVA. We measured contact angle and surface resistance to know the aging characteristic of Polymer surface. And we use SEM to observe the change of the surface shape. Dry flashover voltage test impulse voltage test were carried for the polymer insulator(EVA) . Through this experiment and the analysis we could know the polymers have a good resistance to weathering conditions like as salt spray UV irradiation and mix of them. And we can compare the aging characteristics between Polymers. As a result, we could know that the surface characteristics of PTFE is better than the other. And the degree, electrical characteristics is affected by change of surface shape is not big.

• Journal of the Korean institute of surface engineering
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• v.49 no.2
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• pp.141-146
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• 2016

In this study, electrophoretic paint (E-paint) was deposited on the knife-abraded surface of AZ31 magnesium alloy (AZ31), and its adhesion and corrosion resistance were examined by tape peel-test and salt spray test, respectively. E-paint started to deposit on AZ31 Mg alloy after an inductance time and pores were found in the E-paint layer which is ascribed to hydrogen bubbles generated on the surface during the painting process. The pores disappeared after curing for 15 min at $160^{\circ}C$. The E-paint on AZ31 exhibited good adhesion after immersion in deionized water for 500 h at $40^{\circ}C$. The E-paint sample without scratch showed no corrosion after 1500 h of salt spray test. However, on the scratched sample, blisters were visible adjacent to the scratched sites after 500 h of salt spray test.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2003.10a
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• pp.24-29
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• 2003

Deep sea water has cold temperature, abundant nutrients and minerals, and good water quality that is pathogen-free and stable. Compared with surface water, deep sea water contains more nutrition salt, such as nitrogen and phosphor. Moreover, if has the good balance of minerals. Because of the ability of the spray drying process to produce a free-flowing power considering of spherical particles with a well-defined size distribution and the rapid drying times for heat-sensitive material, spray drying is attractive for a wide range of applications spray drying is a unique unit operation in which powders are produced from a liquid feed in a single processing step. Key component of the process are atomizer, spray chamber. Design of spray chamber should be based on the atomizer type, the production rate, and the particle size required. Because of the complex processes taking place during spray drying, traditional design method are based on pilot-plant tests and empirical scale-up rules. Modern technique such as CFD have a role to play in design and troubleshooting.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.1
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• pp.53-59
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• 2008

Salt is a major component in salt-fermented shrimp with 25% content. There are various types of salts that have different compositions, which may affect the quality of salt-fermented shrimp. We have investigated effects of various salts such as Korean solar salt (KSS), purified salt (PS), sea-concentrated salt (SCS), glasswort (Salicornia herbacea L.) spray solar salt (GSS), glasswort-sea-concentrated salt (GSCS) and spray-dried salt (SDS) on the physicochemical and sensory properties of fermented shrimps. Ammonia nitrogen content of the salted shrimp prepared with SDS was lower than others until 60 day fermentation. At 90 day fermentation, amino nitrogen contents of salted shrimps prepared with GSCS and GSS (980 mg%) were higher than those of the others while sample prepared with SDS showed the lowest amino nitrogen content (680 mg%). Volatile basic nitrogen content of salted shrimp prepared with SDS was also lower than those of the others between 14 and 60 day fermentation and there were differences among samples in the contents of trimethylamine at 180 day fermentation. Sensory evaluation results indicated significant differences in salty, overall taste and overall acceptance among samples. Overall acceptance was significantly higher in salt-fermented shrimp prepared with KSS, SCS, GSS, GSCS and SDS than in fermented shrimp with PS.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.9
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• pp.1764-1768
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• 2009

As the demand of electric power is increasing rapidly, the need of the compact and light electric power device is also increased. Copper clad aluminum (CCA) is newly proposed electrical conductor, because of its light-weight and low-cost characteristics, to replace the existing conductor made of copper. This paper presents the salt-proof characteristics of the copper clad aluminum (CCA) to certificate long time safe operation of the newly proposed electrical conductor. The two types of the CCA conductor were tested in the neutral salt spray tester. The experimental results of two types of the CCA with salt spray were presented in this paper. The results comprise resistance measured data, micro picture of the selected surface, and component measured data according to the elapsed time. The period of the experiment was 1,000 hours. There was no evidence to show the corrosion of CCA during the whole period of the experiments.

• Korean Journal of Materials Research
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• v.32 no.10
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• pp.442-447
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• 2022

Sealing treatment is a post-surface treatment of the plasma spray coating process to improve the corrosion resistance of the coating material. In this study, the effect of the sealing on the corrosion resistance and adhesive strength of the plasma spray-coated alumina coatings was analyzed. For sealing, an epoxy resin was applied to the surface of the coated specimen using a brush. The coated specimen was subjected to a salt spray test for up to 48 hours and microstructural analysis revealed that corrosion in the coating layer/base material interface was suppressed due to the resin sealing. Measurement of the adhesive strength of the specimens subjected to the salt spray test indicated that the adhesive strength of the sealed specimens remained higher than that of the unsealed specimens. In conclusion, the resin sealing treatment for the plasma spray-coated alumina coatings is an effective method for suppressing corrosion in the coating layer/base material interface and maintaining high adhesive strength.

• Proceedings of the Korean Magnestics Society Conference
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• 2015.11a
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• pp.80-80
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• 2015