• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.306-307
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• 2006

The sinter-bonding behavior of iron based powder mixtures was investigated. To produce the green compacts to be joined the following powders based on $H{\ddot{o}}gan{\ddot{a}}s$ AB grade NC 100.24 plain iron powder were used: NC 100.24 as delivered, PNC 30, PNC 60 and NC 100.24 + 4%Cu powder mixtures. Dimensional behaviour of all those materials during the sintering cycle was monitored by dilatometry. Simple ring shaped specimens as the outer parts and cylindrical as the inner parts were pressed. The influence of parts' composition on joining strength was established. Diffusion of alloying elements: copper and phosphorous, across the bonding surface was controlled by metallography, SEM and microanalysis.

• The Journal of Korean Academy of Prosthodontics
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• v.45 no.2
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• pp.216-227
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• 2007

Statement of problem: For the long-term success of removable partial dentures, the bonding between metal framework and denture base resin is one of the important factors. To improve bonding between those, macro-mechanical retentive form that is included metal framework design has been generally used. However it has been known that sealing at the interface between metal framework and denture base resin is very weak, because this method uses mechanical bonding. Purpose: Many studies has been made to find a simple method which induces chemical bond, now various bonding system is applied to clinic. In this experiment, shear bond strengths of heat-cured denture base resin to the surface-treated Co-Cr alloy were measured before and after thermocycling. Chemically treated groups with Alloy $Primer^{TM}$, Super-Bond $C&B^{TM}$, and tribochemically treated group with $Rocatec^{TM}$ system were compared to the beadtreated control group. The data were analyzed with two-way ANOVA. Result: 1. Shear bond strength of bead-treated group is highest, and Alloy $Primer^{TM}$ treated group, Super-Bond $C&B^{TM}$ treated group, RocatecTM system treated group were followed. Statistically significant differences were found in each treated group(p<0.05). 2. Surface treatment and thermocycling affected shear bond strength(p<0.05), however there was no interaction between two factors(p>0.05). 3. Shear bond strengths of bead-treated group and Alloy $Primer^{TM}$ treated group showed no statistically significant difference before and after thermocycling(p>0.05), and those of Super-Bond $C&B^{TM}$ treated group and $Rocatec^{TM}$ system treated group showed statistically significant difference after thermocycling(p<0.05).

• Journal of the Microelectronics and Packaging Society
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• v.14 no.4
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• pp.79-85
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• 2007

This study was focused on the feasibility of ultrasonic bonding of Au stud flip chip bumps on the flexible printed circuit board (FPCB) with three different surface finishes: organic solderability preservative (OSP), electroplated Au and electroless Ni/immersion Au (ENIG). The Au stud flip chip bumps were successfully bonded to the bonding pads of the FPCBs, irrespective of surface finish. The bonding time strongly affected the joint integrity. The shear force increased with increasing bonding time, but the 'bridge' problem between bumps occurred at a bonding time over 2 s. The optimum condition was the ultrasonic bonding on the OSP-finished FPCB for 0.5 s.

• Restorative Dentistry and Endodontics
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• v.30 no.4
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• pp.283-293
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• 2005

The purpose of this study was to evaluate the effect of dual bonding technique by comparing microshear bond strength between two different luting methods of resin cement to tooth dentin. Three dentin bonding systems(All-Bond 2, One-Step, Clearfil SE Bond), two temporary cements (Propac, Freegenol) were used in this study. In groups used conventional luting procedure, dentin surfaces were left untreated. In groups used dual bonding technique, three dentin bonding systems were applied to each dentin surface. All specimens were covered with each temporary cement. The temporary cements were removed and each group was treated using one of three different dentin bonding system. A resin cement was applied to the glass cylinder surface and the cylinder was bonded to the dentin surface. Then, micro-shear bond strength test was performed. For the evaluation of the morphology at the resin/dentin interface, SEM examination was also performed. 1. Conventional luting procedure showed higher micro-shear bond strengths than dual boning technique. However, there were no significant differences. 2. Freegenol showed higher micro-shear bond strengths than Propac, but there were no significant differences. 3. In groups used dual bonding technique, SE Bond showed significantly higher micro-shear bond strengths in One-Step and All-Bond 2 (p<0.05), but there was no significant difference between One-Step and All-Bond 2. 4. In SEM observation, with the use of All-Bond 2 and One-Step, very long and numerous resin tags were observed. This study suggests that there were no findings that the dual bonding technique would be better than the conventional luting procedure.

• The Journal of Korean Academy of Prosthodontics
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• v.43 no.5
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• pp.599-610
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• 2005

Purpose: The success of the bonding between electroformed gold and ceramic is dependent on the surface treatment of the pure gold coping. The purpose of this study was to evaluate the bonding strength between the electroformed gold and ceramic with varying surface treatment. Materials and methods: A total of 32 disks,8 were using conventional ceramometal alloy, 24 were using electroforming technique as recommended by manufacturer, were prepared. 24 electroformed disks were divided 3 groups according to surface treatment, i.e. 50 microns aluminium oxide sandblasting(GES-Sand), gold bonder treatment(GES-Bond) and $Rocatec^{TM}$ system(GES-Rocatec). For control group of conventional alloy 50 microns aluminium oxide treatment was done(V-Supragold). Energy dispersive x-ray analysis and scanning electron microscope image were observed. Using universal testing machine, shear bond strength and bonding failure mode at metal-porcelain interface were measured. Results and Conclusion: The following conclusions were drawn: 1. In the energy dispersive x-ray analysis, the Au was main component in electroformed gold(99.9wt%). After surface treatment, a little amount of $Al_2O_3(2.4wt%)$ were found in GES-Sand, and $SiO_2(4wt%)$ in GES-Bond. In GES-Rocatec, however, a large amount of $SiO_2(17.4wt%)$ were found. 2. In the scanning electron microscopy, similar pattern of surface irregu larities were observed in V-Supragold and GES-Sand. In GES-Bond, surface irregularities were increased and globular ceramic particles were observed. In GES-Rocatec, a large amount of silica particles attached to metal surface with increased surface irregularities were observed. 3. The mean shear bond strength values(MPa) in order were $22.9{\pm}3.7(V-Supragold),\;22.1{\pm}3.8(GES-Bond),\;20.1{\pm}2.8(GES-Rocatec)\;and\;13.0{\pm}1.4(GES-Sand)$. There was no significant difference between V-Supragold, GES-Bond, and GES-Rocatec. (P>0.05) 4. Most bonding failures modes were adhesive type in GES-Sand. However, in V-Supragold, GES-Bond and GES-Rocatec, cohesive and combination failures were commonly observed. From the result, with proper surface treatment method electroformed gold may have enough strength compare to conventional ceramometal alloy.

• Journal of Adhesion and Interface
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• v.7 no.3
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• pp.26-33
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• 2006

Nylon fabrics were corona treated with different current intensity (5, 10, 15, 20 A) and feeding speed (5, 10, 15 m/min). We confirmed the change of nylon fabrics surface using X-ray diffraction apparatus, scanning electron microscopy (SEM) and X-ray photoelectron spectrometer (ESCALAB). And the change of physical properties through measuring the tensile strength, tear strength, bonding and wet bonding strength. Thermosetting reactive polyurethane hot melt adhesive was used in the adhesion of nylon fabrics. Functional groups were introduced on nylon fabric surface by treating the fabrics in air atmosphere with corona discharge, and the result adhesion was improved. Bonding strength of the nylon fabric treated with corona was increased with increasing current intensity and decreasing feeding speed.

• Journal of Korea Foundry Society
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• v.13 no.1
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• pp.42-49
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• 1993

Conventional manufacturing process for cast iron-babbitt metal composite is complicate and bimetallic bonding by centrifugal casting is also difficult because their melting point is largely different and nonmetallic inclusion exists on outer shell. This study is aiming to simplify multistage process by adding Cu-powder as insert metals during cast iron solidification. The variables on fabrication of composite pipe are mold rotating speed and inner surface temperature of outer metal. The optimum temperature range for fusion bonding between cast iron and Cu-layer was $1100^{\circ}C-1140^{\circ}C$ in case of mold rotating speed was 700rpm. When the inner surface of Cu-layer was at $900^{\circ}C$, the value of interfacial hardness between Cu-layer and babbitt metal were higher than Cu-matrix by forming diffusion layer, interfacial products between Cu-layer and babbitt metal are proved to be $Cu_6Sn_5({\eta})$by XRD.

• Advanced Composite Materials
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• v.18 no.3
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• pp.221-232
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• 2009

The allylamine plasma treatment is used to modify the surface properties of vapor grown carbon fibers (VGCF). It is to improve the interfacial bonding between the VGCF and epoxy matrix. The allylamine plasma process was performed by batch process in a vacuum chamber, using gas injection followed by plasma discharge for the durations of 20, 40 and 60 min. The interdependence of mechanical properties on the VGCF contents, treatment time and interfacial bonding between VGCF/ep was investigated. The interfacial bonding between VGCF and epoxy matrix was observed by scanning electron microscopy (SEM) micrographs of nanocomposites fracture surfaces. The changes in the mechanical properties of VGCF/ep, such as the tensile modulus and strength were discussed. The mechanical properties of allylamine plasma treated (AAPT) VGCF/ep were compared with those of raw VGCF/ep. The tensile strength and modulus of allyamine plasma treated VGCF40 (40 min treatment)/ep demonstrated a higher value than those of other samples. The mechanical properties were increased with the allyamine plasma treatment due to the improved adhesion at VGCF/ep interface. The modification of the carbon nanofibers surface was observed by transmission electron microscopy (TEM). SEM micrographs showed an excellent dispersion of VGCF in epoxy matrix by ultrasonic method.

• Journal of the Korean Society of Industry Convergence
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• v.25 no.2_2
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• pp.309-314
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• 2022

The bonding strength [ISO22674] test was conducted by firing a dedicated ceramic powder on the surface of the dental titanium material treated with micro-arc oxidation. In the test group, an average result value of 34.34 MPa was obtained, and in the control group, a result value of 21.53 MPa was obtained. The bonding strength of the test group was higher than that of the control group by 12.81 MPa, resulting in a 37% improvement in durability of the dental artificial tooth ceramic restoration.

• Journal of the Semiconductor & Display Technology
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• v.20 no.4
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• pp.125-129
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• 2021

We investigated the electronic property and atomic structure for chalcopyrite (CH) Al_xGa_1-xAs semiconductor by using first-principles FPLMTO method. The CH-Al_xGa_1-xAs exhibits a p-type semiconductor with a direct band-gap. For low Al concentration unoccupied hole-carriers are induced, but for high Al concentration it is formed a localized bonding or anti-bonding state below Fermi level. The hybridization of Al(3s)-Ga(4s, or 4p) is larger than that of Al(3s)-As(4s, or 4p). And the Al film on As-terminated surface, Al/AsGa(001), is more energetically favorable one than that on Ga-terminated (001) surface. Consequently, the band-gap of CH-Al_xGa_1-xAs system increases exponentially with increasing Al concentration. The change of lattice parameter is shown two different configurations with increasing Al concentration. The calculated lattice parameters for CH-Al_xGa_1-xAs system are compared to the experimental ones of zinc-blend GaAs and AlAs.