• Journal of Advanced Marine Engineering and Technology
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• v.13 no.4
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• pp.33-39
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• 1989

A turbulent premixed flames of layer formed between burned hot gas and unburned mixture were investigated by means of schlieren photograph with fluctuations of temperature and ion current. The combustion intensity between burned hot gas and shear layer was higher than the intensity between unburned mixture and shear layer. A wrinkled laminar flame and flamelet were appeared at downstream to exist and distributed reaction zone was at upstream as a result of analyzed probability density functions of temperature fluctuation. The initial combustion intensity of reaction zone of eddy between burned hot gas and shear layer was higher than that of final, flowing downstream, and vice versa between unburned mixture and shear layer.

• Textile Coloration and Finishing
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• v.19 no.5
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• pp.37-40
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• 2007

The electrostatic layer-by-layer technique provides a convenient way to control the construction of ultrathin films at nano-scale ranges and can be easily obtained. It can be also applicable to fiber substrate with dye compounds. We have fabricated multilayer dye films using diazonium resin and three couplers, which are prepared by self-assembly approach. This method is based on layer-by-layer deposition using electrostatic attraction between oppositely charged ions. Beside, the diazo coupling reaction proceeded to form azo dye layer on the PET fibers the same time. The corresponding results of the multilayer films have been discussed on the level of color strength (K/S).

• Nuclear Engineering and Technology
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• v.55 no.3
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• pp.902-907
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• 2023

To understand the eutectic reaction mechanism and the relocation behavior of the core debris is indispensable for the safety assessment of core disruptive accidents (CDAs) in sodium-cooled fast reactors (SFRs). This paper addresses reaction products and their distribution of the eutectic melting/solidifying reaction of boron carbide (B₄C) and stainless-steel (SS). The influence of the existence of carbon on the B₄C-SS eutectic reaction was investigated by comparing the iron boride (FeB)-SS reaction by Raman spectroscopy with Multivariate Curve Resolution (MCR) analysis. The scanning electron microscopy with dispersive X-ray spectrometer was also used to investigate the elemental information of the pure metals such as Cr, Ni, and Fe. In the B₄C-SS samples, a new layer was formed between B₄C/SS interface, and the layer was confirmed that the formed layer corresponded to amorphous carbon (graphite) or FeB or Fe₂B. In contrast, a new layer was not clearly formed between FeB and SS interface in the FeB-SS samples. All samples observed the Cr-rich domain and Fe and Ni-rich domain after the reaction. These domains might be formed during the solidifying process.

• Korean Journal of Metals and Materials
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• v.49 no.11
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• pp.910-915
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• 2011

The microstructures and mechanical properties of roll-bonded STS439/Al1050/STS304 clad materials were investigated after an annealing process at various temperatures. Interfacial layer was developed at the STS439/Al1050 and Al1050/STS304 interfaces at $550^{\circ}C$. STS439/Al1050/STS304 clad metals fractured suddenly in a single step and the fracture decreased with increasing annealing temperatures at $450^{\circ}C$. After annealing at $550^{\circ}C$, samples fractured in three steps with each layer fracturing independently. Interfacial layers formed at $550^{\circ}C$ with a high Vickers microhardness were found to be brittle. During tensile testing, periodic parallel cracks were observed at the interfacial reaction layer. Observed micro-void between Al1050 and the interfacial layer was found to weaken the Al1050/reaction layer interface, leading to the total separation between Al1050 and the reaction layer.

• Journal of Korea Foundry Society
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• v.15 no.3
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• pp.272-282
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• 1995

Iron-based metal matrix composites have been recently investigated for the use of inexpensive abrasion resistance material. This paper carried out to investigate the in-situ reaction effects on the microstructural characteristics and the formation mechanism of tungsten carbides in a white cast iron matrix. The specimens of Fe-3.2%C-2.8%Si alloy cast-bonded with tungsten wire were cast in the metal mold and isothermally heat treated at $950^{\circ}C$ up to 48 hours. The typical microstructure of heat treated specimens showed the reaction layer of WC at the interface of tungsten wire and the carbon depletion zone between the WC layer and the matrix. During the formation of WC layer, if the carbon supply is insufficient due to the decarburization of matrix or the isolation of matrix by cast-bonded W wires, the reaction layer develops coarse hexagonal crystalline WC. From the microstructural investigation, it was found that the volume of WC layer and the carbon depletion zone increased linearly with the isothermal heat treating time. This results supported that the formation rate of WC in the white cast iron matrix is controlled by the interfacial reaction with a constant reaction rate.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.6
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• pp.1047-1052
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• 2002

The impact value, the interfacial shear strength, the tensile strength and the fracture strain of Nb/MoSi$_2$laminate composites, which were associated with the interfacial reaction layer, have been investigated. Three types of Nb/MoSi$_2$ laminate composites alternating sintered MoSi$_2$ layers and Nb foils were fabricated as the parameter of hot press temperature. The thickness of interfacial reaction layer of Nb/MoSi$_2$ laminate composites increased with increasing the fabrication temperature. The growth of interfacial reaction layer increased the interfacial shear strength and led to the decrease of impact value in Nb/MoSi$_2$ laminate composites. It was also found that in order to maximize the fracture energy of Nb/MoSi$_2$ laminate composites, interfacial shear strength and the thickness of interfacial reaction layer must be secured appropriately.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.11a
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• pp.277-284
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• 2000

Using the large diameter (D ＝ 2,500mm, L ＝ 40m) batter steel pipe piles, designed as compression piles but used as reaction piles during the static compression load test of socketed test piles (D ＝ 1,000mm, L ＝ 40m), static pile load tests for large diameter instrumented rock-socketed piles were performed. The reaction steel pipe piles were driven 20m into the marine deposit and weathered rock layer and then l0m socketed with reinforced concrete through the weathered rock layer and into hard rock layer. Steel pipe and concrete in the steel pile part, and concrete and rebars in the socketed parts were instrumented to measure strains in each part. The pullout amounts of reaction pile heads were also measured with LVDT. During the static pile load test, total compressional load of about 20MN was loaded on the head of test piles, but load above 20MN was not loaded due to lack of loading capacity of loading system. Over the course of the study, maximum pullout amount up to 7mm was measured in the heads of reaction piles when loaded op to 10MN and 1mm of pullout amount was measured. More than 85% of pullout load was transfered in the residual weathered rock layer and about 10% in the soft rock layer, which was somewhat different transfer mechanism in the static compressional load tests.

• Journal of Korea Foundry Society
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• v.22 no.2
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• pp.89-96
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• 2002

This study examined the effects of adding Zn to Sn-3.5Ag solder on the microstructure changes and behavior of interface reaction of the solder joint with Cu substrate. The solder/Cu joints were examined with microscope to observe the characteristics of microstructure changes and interfacial reaction layer with aging treatment for up to 120 days at $150^{\circ}C$. Results of the microstructure changes showed that the microstructures were coarsened with aging treatment, while adding 1%Zn suppresses coarsening microstructures. The Sn-3.5Ag/Cu had a fast growth rate of the reaction layer in comparison with the Sn-3.5Ag-1Zn at the aging temperature of $150^{\circ}C$. Through the SEM/EDS analysis of solder joint, it was proved that intermetallic layer was $Cu_6Sn_5$ phase and aged specimens showed that intermetallic layer grew in proportion to $t^{1/2}$, and the precipitate of $Ag_3Sn$ occur to both inner layer and interface of layer and solder. In case of Zn-containing composite solder, $Cu_6Sn_5$ phase formed at the side of substrate and Cu-Zn-Sn phase formed at the other side in double layer. It seems that Cu-Zn-Sn phase formed at solder side did a roll of banrier to suppress the growth of the $Cu_6Sn_5$ layer during the aging treatment.

• Journal of Korea Foundry Society
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• v.30 no.2
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• pp.76-82
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• 2010

Effect of reaction time and sludge formation on the thickness of die soldering reaction layer has been studied in Al-9Si-0.3Mg casting alloy. Ternary ${\alpha}_{bcc}-Al_8Fe_2Si$ and ${\alpha}_{hcp}-Al_8Fe_2Si$ intermetallic compounds formed at the interface of SKD61 tool steel by interaction diffusion of Al, Fe and Si atoms after 0.5hr and 6hr immersion time, respectively. Binary ${\eta}-Fe_2Al_5$ additionally formed at the interface of SKD61 tool steel after 10hr immersion time. Thickness of soldering reaction layer in die surface increased as immersion time increased from 0.5hr to 24hr. Sludge formation was ascertained in the samples which were immersed in the melts more than 10hr. Reaction of die soldering after sludge formation was more accelerated than that of before sludge formation due to a decrease in Fe content, followed by higher diffusion rate of Al in the melt by sludge formation.

• Journal of Korea Foundry Society
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• v.28 no.6
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• pp.282-287
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• 2008

The effect of CaO mold on the formation of reaction layer was investigated. CaO mold was prepared by mixing of Colloidal silica($NALCO^{(R)}$ 1130) and an $ZrO_2$, CaO at room temperature. The dried at $20{\pm}3^{\circ}C$, 75% humidity for 12hrs. Sample was prepared from the Cp-Ti(grade-2) and melted by high frequence induction melting system in the vacuum condition. The react ion layer of Ti was confirmed by optical microscopy, microhardness(Hv) and X-ray diffraction. Thickness of reaction layer using the CaO stabilized ZrO2 was thinner than the CaO added ZrO2. And thickness of reaction layer were decreased with decreasing pH of slurry. CaO addition in the slurry could not controlled reaction between molten Ti and investment mold. On the other hand, the CaO chemical bonded ZrO2 by stabilization treatment could controlled reaction between molten Ti and investment mold.