• Proceedings of the Korean Powder Metallurgy Institute Conference
• /
• 2006.09a
• /
• pp.511-512
• /
• 2006

Tungsten coatings with different interlayers onto the oxygen-free copper substrates were fabricated by atmosphere plasma spraying. The effects of different interlayers of NiCrAl, NiAl and W/Cu on bonding strength were studied. SEM, EDS and XRD were used to investigate the photographs and compositions of these coatings. The tungsten coatings with different initial particle sizes resulted in different microstructures. Oxidation was not detected in the tungsten coating, but in the interlayer, it was found by both XRD and EDS. The tungsten coating deposited directly onto the copper substrate presented higher bonding strength than those with different interlayers.

• Applied Science and Convergence Technology
• /
• v.24 no.5
• /
• pp.142-150
• /
• 2015

A failure analysis of tungsten filaments used in quadrupole mass spectrometer for plasma process monitoring was carried by using SEM and EDS. Failed at high temperature, filaments showed two kinds of failure modes. The one is that diameter of filament became thinner gradually and finally snapped. The other is that filament abruptly snapped almost at a right angle. The EDS analysis showed Fe and C, including W and Fe, on the surface of failed filament. when failed filaments were treated with plasma in mixture of Ar and $CF_4$, the amount of Fe and C decreased. The failure analysis of filament showed that the cause of filament failure is thermal evaporation and grain growth of tungsten at high temperature.

• Journal of the Korean Ceramic Society
• /
• v.45 no.10
• /
• pp.589-593
• /
• 2008

The hydroxyapatite with different amounts of strontium was synthesized with wet chemical technique. The structural, morphological and chemical characterizations for the prepared hydroxyapatite with various strontium amounts were carried out with XRD, SEM, EDS, and FT-IR. Strontium is quantitatively incorporated into hydroxyapatite where its substitution for calcium provokes a well distribution in the EDS mapping and a linear shift of the infrared absorption bands of the hydroxyl and phosphate groups, coherent with the greater ionic radius of strontium.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.27 no.5
• /
• pp.229-234
• /
• 2017

In this study, TiAl alloy was fabricated by a centrifugal casting method for turbo charge of automotive. Optimum conditions for defectless morphology using various ceramic mold were investigated. The crystal structure, microstructure, and chemical composition of the TiAl prepared by centrifugal casting were studied by X-ray diffractometer (XRD), optical microscopy (OM), field emission scanning electron microscopy (FE-SEM) and energy dispersive spectroscopy (EDS), microvickers hardness analyzer (HV). Two kinds of dendrite structures were observed with 4-fold and 6-fold symmetries. The FE-SEM, EDS and HV examinations of the as-cast TiAl showed that the thickness of the oxide layer (${\alpha}$-case) was typically less than $50{\mu}m$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.07a
• /
• pp.489-492
• /
• 2003

In this paper, we experimented on the deterioration process of power supply cords and analyzed the heating temperature of each part of those cords. We also analyzed the surface states, metallurgical structures surface structures and compositions of the wire melted by over-current. In the results of the analyses, the covering began to be deteriorated from the inside. The heating temperature of extension cord was higher than that of plug body. The dendrite structures appeared at the melted wire. By the SEM and EDS analyses, the dendrite structure showed the growth of copper oxide. We found out the characteristics of PVC insulated flexible cords by over-current from the above experiments and analyses. These results may be useful data in the analyses of deterioration causes of power supply cords.

• Journal of Microbiology and Biotechnology
• /
• v.23 no.2
• /
• pp.205-210
• /
• 2013

Thiol-ene polymerization is a versatile tool for several applications. Here we report the preparation of epoxide groups containing thiol-ene photocurable polymeric support and the covalent immobilization of ${\alpha}$-amylase onto these polymeric materials. The morphology of the polymeric support was characterized by scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) coupled with SEM was used to explore the chemical composition. The polymeric support and the immobilization of the enzyme were characterized by FTIR analysis. SEM-EDS and FTIR results showed that the enzyme was successfully covalently attached to the polymeric support. The immobilization efficiency and enzyme activity of ${\alpha}$-amylase were examined at various pH (5.0-8.0) and temperature ($30-80^{\circ}C$) values. The storage stability and reusability of immobilized ${\alpha}$-amylase were investigated. The immobilization yield was $276{\pm}1.6$ mg per gram of polymeric support. Enzyme assays demonstrated that the immobilized enzyme exhibited better thermostability than the free one. The storage stability and reusability were improved by the immobilization on this enzyme support. Free enzyme lost its activity completely within 15 days. On the other hand, the immobilized enzyme retained 86.7% of its activity after 30 days. These results confirm that ${\alpha}$-amylase was successfully immobilized and gained a more stable character compared with the free one.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.27 no.1
• /
• pp.28-33
• /
• 2017

SiC fiber can be used up to $1800^{\circ}C$ in both inert and air atmosphere without any problems such as melting and oxidation. SiC fibers can be applied to dust filtering processes as a bag filter at a high temperature above $700^{\circ}C$, which is far beyond the temperature range of currently available industrial bag filter. However the studies for the degradation of SiC fibers were still lacked in the harsh environment of steel industries and thermoelectric power plants. In this study, SiC fibers were reacted with steel dust and thermal power plant dust at a high temperature of $500^{\circ}C$ or higher, and the degraded shape of the fiber surface was observed by SEM. Also the degree of oxygen diffusion on the surface and inside of SiC fiber was analyzed by EDS.

• Journal of the Korean Society for Heat Treatment
• /
• v.12 no.1
• /
• pp.47-54
• /
• 1999

Microstructure of Al-Si coated PWA 1426 alloy was studied. Diffusion coated specimens were heat treated for 4hr at $870{\sim}1087^{\circ}C$ and then were examined the changes of microstructure and interfacial compound by optical microscopy, SEM and EDS. According to the result of EDS, it is supposed that the coated layer was composed of $Ni_2Al_3$. When diffusion treatment was conducted at $1087^{\circ}C$, coated layer varied from $Ni_2Al_3$ to NiAl phase and composed of mixed, denuded and inter-diffusion layer.

• Journal of Powder Materials
• /
• v.2 no.1
• /
• pp.53-62
• /
• 1995

TLP(Transient-Liquid-Phase) bonding of Fe-base MA956 ODS alloy was performed. As insert metal a commercially available Ni-base alloy(MBF50) and an MA956 alloy with additive elements of 7wt% Si and 1wt% B were used. To confirm the idea that a concurrent use of MA956 powder with Insert metals can enhance the homogenization of constituent elements and thereby reduce the thickness of joint interface, MA956 powder was also inserted In a form of sheet. SEM observation and EDS analysis revealed that Cr-rich phase was formed in the bonded interface in initial stage of isothermal solidification during the bonding process, irrespective of kind of insert metals. Measurement of hardeness in the region of bonded interface and EDS analysis showed that a complete homogenization of composition could not be obtained especially in case of MBF50. Joints using either BSi insert metals only or BSi insert together with MA956 powder interlayer showed, however, a remarkable improvement in a compositional homogenization, even though a rapid grain growth in the bonded interface could not be hindered.

• Journal of the Korean Geotechnical Society
• /
• v.28 no.10
• /
• pp.69-77
• /
• 2012

Clogging of drainage pipes by scale is an important problem in civil engineering works. Although scale deposits can be removed by acid treatment or water jetting, these treatments are costly and have many disadvantages. In this study, scale samples from tunnel drainage pipes were analyzed using SEM-EDS and XRD. The main ingredient in scale was $CaCO_3$ of the calcite crystal form. Drainage experiments and recirculation type experiments were conducted to control and remove scale deposits, which were determined through visual and weight measuring analysis. As a result, Quantum Stick has the effect of limiting formation of scale.