• The Journal of Advanced Prosthodontics
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• v.8 no.1
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• pp.1-8
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• 2016

PURPOSE. The purpose of this study was to evaluate the efficacy of two different metal conditioners for non-precious metal alloys for the bonding of porcelain to a cobalt-chromium (Co-Cr) alloy. MATERIALS AND METHODS. Disk-shaped specimens ($2.5{\times}10.0mm$) were cast with Co-Cr alloy and used as adherend materials. The bonding surfaces were polished with a 600-grid silicon carbide paper and airborne-particle abraded using $110{\mu}m$ alumina particles. Bonding specimens were fabricated by applying and firing either of the metal conditioners on the airborne-particle abraded surface, followed by firing porcelain into 5 mm in diameter and 3 mm in height. Specimens without metal conditioner were also fabricated. Shear bond strength for each group (n=8) were measured and compared (${\alpha}=.05$). Sectional view of bonding interface was observed by SEM. EDS analysis was performed to determine the chemical elements of metal conditioners and to determine the failure modes after shear test. RESULTS. There were significant differences among three groups, and two metal conditioner-applied groups showed significantly higher values compared to the non-metal conditioner group. The SEM observation of the sectional view at bonding interface revealed loose contact at porcelain-alloy surface for non-metal conditioner group, however, close contact at both alloy-metal conditioner and metal conditioner-porcelain interfaces for both metal conditioner-applied groups. All the specimens showed mixed failures. EDS analysis showed that one metal conditioner was Si-based material, and another was Ti-based material. Si-based metal conditioner showed higher bond strengths compared to the Ti-based metal conditioner, but exhibited more porous failure surface failure. CONCLUSION. Based on the results of this study, it can be stated that the application of metal conditioner is recommended for the bonding of porcelain to cobalt-chromium alloys.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.32 no.5
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• pp.212-217
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• 2022

Large thermal stress due to the difference between silicon carbide and graphite's coefficients of thermal expansion could be formed during crystal growing process of silicon carbide (SiC) at high temperature. The large thermal stress could separate the SiC seed crystals from graphite components, which bring about the drop of the seed crystal during crystal growth. However, the bonding properties of SiC seed crystal module has hardly reported so far. In this study, SiC and graphite were bonded using 3 types of bonding agents and a three-point bending tests using a mixed-mode flexure test were conducted for the bonded samples to evaluate the bonding characteristics between SiC and graphite. Raman spectroscopy, X-ray Photoelectron Spectroscopy, and X-ray Computed Tomography were used to analyze the bonding characteristics and the microstructures of the SiC-graphite interfaces bonded with the bonding agents. As results, an excellent bonding agent was chosen to fabricate SiC seed crystal module with 50 mm in diameter. An SiC single crystal with 50 mm in diameter was successfully grown without falling out during top seeded solution growth of SiC at high temperature.

• Proceedings of the KIEE Conference
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• 2001.11a
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• pp.16-19
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• 2001

DLC films are deposited using a modified FCVA system. Carbon amorphous networks, chemical bonding states, $sp^3$ fraction, interfaces, and structures are studied as a function of substrate voltage ($0{\sim}-250V$). The $sp^3$ content in the films is evaluated by analyzing the XPS spectra(C1s). The structural properties of the surface, bulk, and interfacial layers in DLC/Si systems are quantitatively analyzed by employing XRR method. As the substrate voltage is increased, the $sp^3$ fraction is decreased by means of XPS and Raman spectroscopy. In addition, the structural properties (interfacial layer, contamination layer, and sp3 fraction) derived from XPS depth profile are relatively correlated with the XRR results.

• Structural Engineering and Mechanics
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• v.34 no.4
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• pp.449-474
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• 2010

A smart hollow cylinder consisting of a host functionally graded elastic core layer and two surface homogeneous piezoelectric layers is presented in this paper. The bonding between the layers can be perfect or imperfect, depending on the parameters taken in the general linear spring-layer interface model. The effect of such weak interfaces on free vibration and steady-state response is then investigated. Piezoelectric layers at inner and outer surfaces are polarized axially or radially and act as a sensor and an actuator respectively. For a simply supported condition, the state equations with non-constant coefficients are obtained directly from the formulations of elasticity/piezoelasticity. An approximate laminated model is then introduced for the sake of solving the state equations conveniently. It is further assumed that the hollow cylinder is embedded in an elastic medium and is simultaneously filled with compressible fluid. The interaction between the structure and its surrounding media is taken into account. Numerical examples are finally given with discussions on the effect of some related parameters.

• Journal of Welding and Joining
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• v.27 no.3
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• pp.92-96
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• 2009

Metallic sandwich plate has many good properties such as high specific stiffness, high specific strength, good impact absorptivity, effective thermal insulation and soundproofing. In our study, a new bonding method, 3-layer roll projection welding, is introduced to fabricate the metallic sandwich plate. The new method uses a pair of roll electrodes like the seam welding, and projection welding is made at two internal interfaces of the 3-layer weldment consisting of a structured inner sheet and a pair of skin sheets. During the welding process, skin sheet temperature are measured to produce metallic sandwich plate with uniform and good quality. But it is difficult to observe or measure the temperature at the welding points during welding process because the welding points exist at the internal interfaces. Therefore FEM numerical analysis using ABAQUS is conducted to estimate the generated heat at the welding points with different welding conditions.

• Advances in concrete construction
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• v.13 no.3
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• pp.265-279
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• 2022

The roughness of substrate concrete interfaces before new concrete placement has a major effect on the interface bond behaviour. However, there are challenges associated with the consistency of the final roughness interface prepared using conventional roughness preparation methods which influences the interface bond performance. In this study, five quantitative interface roughness textures with different roughness tooth angles, depths, and tooth distribution were created to ensure consistency of interface roughness and to evaluate the bond behaviour at a precast and new concrete interface using the splitting tensile test, slant shear test, and double-shear test. In addition, smooth interface specimens and two separate the pitting interface roughness were also utilized. Obtained results indicate that the quantitative roughness has a very limited effect on the interface tensile bond strength if no extra micro-roughness or bonding agent is added at the interface. The roughness method however causes enhanced shear bond strength at the interface. Increased tooth depth improved both the tensile and shear bond strength of the interfaces, while the tooth distribution mainly influenced the shear bond strength. Major failure modes of the test specimens include interface failure, splitting cracks, and sliding failure, and are influenced by the tooth depth and tooth distribution. Furthermore, the interface properties were obtained and presented while a comparison between the different testing methods, in terms of bond strength, was performed.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1988-1990
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• 1996

In this work, we have grown or evaporated thermal oxide and E-beam oxide on the (100) oriented n-type silicon wafers, respectively and they were directly bonded with another silicon wafer after hydrophilization using solutions of three types of $HNO_3$, $H_{2}SO_{4}$ and $NH_{4}OH$. Changes of average surface roughness after hydrophilizations of the single crystalline silicon wafer, thermal oxide and E-beam evaporated silicon oxide were studied using atomic force microscope. Bonding interfaces of the bonded pairs were inspected using scanning electron microscope. Void and non-contact area of the bonded pairs were also inspected using infrared transmission microscope.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.121-126
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• 2000

Metal/Ceramic structures have many attractive properties, with great potential for applications that demand high stiffness, as well as chemical and biological stability, thermal and electrical insulation. They are currently in use for mechanical and thermal protection in cutting tool and engine parts. With all their great advantage, ceramics suffer from one major problem they are brittle, and are especially susceptible to cracking from surface contacts. Delamination at the interfaces with adjacent layers is a particularly disturbing problem, and can cause premature failure of a composite system. so determination of adhesive properties of coating is one of the most important problems for the extension of the use of coated materials. In this work, mechanical characteristics of Interface of ceramic/Metal composites are evaluated by means of hardness test, indentation test apparent interfacial toughness and bonding strength test. The interface indentation test provides a relation between the applied load(P) and the length of the crack(a) created at the interface between the coating and the substrate.

• Korean Journal of Materials Research
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• v.4 no.2
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• pp.127-135
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• 1994

We investigated the bonding interfaces of directly-bonded Si-Si and $Si-Sio_{2}$/Si wafer pairs. By the angle lapping-delineation, anisotropic etching, and (FIR)-TEM observation methods, we studied on the interface defects and the transient region originated from the interface stress, the various types of voids, the formation and stability of interfacial oxide. We also compared the interface image of the bonded $Si-Sio_{2}$ with that of a typically grown $Si-Sio_{2}$.

• Journal of the Korean institute of surface engineering
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• v.34 no.1
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• pp.33-38
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• 2001

10cm-diameter Si(100)∥$1.3\mu\textrm{m}$-X$1.3_2$X$1.3\mu\textrm{m}$-$SiO_2$∥Si(100) afers were prepared using a fast linear annealing (FLA) equipment. 1.3$\mu\textrm{m}$-thick $SiO_2$ films were grown by dry oxidation process. After cleaning and premating the wafers in a class 100 clean room, they were heat treated using with the FLA and conventional electric furnace. Bonded area and bond strength of wafer pairs were measured using a infrared (IR) camera and razor blade crack opening method, respectively. It was confinmed that the bonded area by FLA was around 99% and the bond strength value reached 2172mJ/$\m^2$, which is equivalent to theoritical bond strength. Our result implies that thick $SiO_2$ SOI may be prepared more easily by using $SiO_2$$SiO_2$ bonding interfaces then those of Si/$SiO_2$'s.