• Restorative Dentistry and Endodontics
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• 제42권1호
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• pp.1-8
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• 2017

Objectives: The purpose of this study was to evaluate the effect of adhesive luting on the fracture resistance of zirconia compared to that of a composite resin and a lithium disilicate glass ceramic. Materials and Methods: The specimens (dimension: $2mm{\times}2mm{\times}25mm$) of the composite resin, lithium disilicate glass ceramic, and yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) were prepared. These were then divided into nine groups: three non-luting groups, three non-adhesive luting groups, and three adhesive luting groups, for each restorative material. In the non-luting groups, specimens were placed on the bovine tooth without any luting agents. In the non-adhesive luting groups, only zinc phosphate cement was used for luting the specimen to the bovine tooth. In the adhesive luting groups, specimens were pretreated, and the adhesive luting procedure was performed using a self-adhesive resin cement. For all the groups, a flexural test was performed using universal testing machine, in which the fracture resistance was measured by recording the force at which the specimen was fractured. Results: The fracture resistance after adhesive luting increased by approximately 29% in the case of the composite resin, 26% in the case of the lithium disilicate glass ceramic, and only 2% in the case of Y-TZP as compared to non-adhesive luting. Conclusions: The fracture resistance of Y-TZP did not increased significantly after adhesive luting as compared to that of the composite resin and the lithium disilicate glass ceramic.

• International Journal of Automotive Technology
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• 제7권5호
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• pp.565-570
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• 2006

The development of a light-weight vehicle is in great demand for enhancement of fule efficiency and dynamic performance. The vehicle weight can be reduced effectively by using lightweight materials such as aluminum and magnesium. However, if such materials are used in vehicles, there are often instances when different materials such as aluminum and steel need to be joined to each other. The conventional joining method, namely resistance spot welding, cannot be used in joining different materials. Self-piercing rivet(SPR) and adhesive bonding, however, are good alternatives to resistance spot welding. This paper is concerned with the crushing test of double hat-shaped member made by resistance spot welding, SPR and adhesive bonding. Various parameters of crashworthiness are analyzed and evaluated. Based on these results, the applicability of SPR and adhesive bonding are proposed as an alternative to resistance spot welding.

• Composites Research
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• 제31권4호
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• pp.151-155
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• 2018

기계적 조인트와 접착 조인트는 구조물의 일반적인 접합 방법이다. 접착 조인트는 기계적 체결법에 비해 넓은 면적에 하중이 분포되고 우수한 피로 특성을 가진다. 이러한 특성에도 불구하고, 접착 조인트는 환경조건이나 작업자의 숙련도에 대한 접착 건전성이 크게 달라진다. 따라서 접착 조인트의 건전성을 평가 할 수 있는 기술이 필요하다. CNT를 접착제에 분산시켜 접착조인트의 전기적 특성을 측정하는 전기저항법은 결함을 검출하는 매우 유망한 기술이다. 본 논문에서는 초음파 분쇄기와 3-roll-mill을 이용하여 접착제에 CNT를 균일하게 분산시켰으며, 알루미늄-알루미늄 단일 접착 조인트를 제작하여 탄소나노튜브(CNT) 함량에 따른 정적 강도의 변화를 평가하고, 전기저항법을 이용하여 결함탐지능을 평가하였다.

• Journal of Welding and Joining
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• 제29권5호
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• pp.72-81
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• 2011

In the present day, the needs of new steel for lightweight car-body have been increased in the automotive industry. however, the resistance spot welding is difficult to apply to the new steel because of the narrow weld current range and defects. As the solutions to these problems, adhesive bonding process is proposed. Adhesive bonding which reduce noise and vibration can be applied to joining the new steel. In this study, crash tests of b-pillar applied the resistance spot welding, structural adhesive bonding, the mixture of the structural adhesives and resistance spot welding were performed. And FEM crash model for b-pillar applied the structural adhesive bonding was developed. The results of experiment and analysis on b-pillar crash test were compared to verify the validity.

• Composites Research
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• 제28권6호
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• pp.348-355
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• 2015

접착 조인트는 환경조건 및 작업자의 숙련도에 따라 접착강도가 크게 변화될 수 있으므로 이에 대한 비파괴 검사법은 매우 중요하다. 최근 접착제에 1-2 wt%의 CNT를 첨가하고 저항변화를 측정하여 접착 체결부의 내부 결함을 검출하는 전기저항법이 제시되었다. 전기저항법에서는 동일조건에서 접착조인트의 저항값이 일정하도록 하기 위하여 CNT의 균일한 분산이 매우 중요하며 이에 따라 결함 검출의 정확도가 좌우된다. 본 연구에서는 4가지 분산 방법으로 CNT를 접착제에 분산시켜 접착조인트을 제작하고 전기적 물리량을 측정하였다. 초음파를 이용한 CNT의 전처리 및 기화과정, 물리적 교반 방법등을 선정하여 효율적인 분산방법을 정립하고 분산성을 평가할 수 있는 척도를 제시하였으며 일반적인 분산 방법 대비 선정된 분산 방법을 적용했을 때 전기저항법의 결함검출능을 비교하였다.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.399-400
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• 2006

M390 microclean(R) of $B{\ddot{o}}hler$ Edelstahl is a powder metallurgical plastic mould steel with a high level of corrosion and wear resistance and therefore often used in the plastics processing industry. But as a consequence of rapidly advancing developments in the plastics processing industry the required level of wear resistance of tool steels in this field is constantly rising. For that reason a new PM tool steel with higher hardness values and an increased amount of primary carbides has been developed to improve the resistance against abrasive and adhesive wear. The wear resistance of both steels against adhesive situations for components of the plastification unit of injection moulding machines has been tested with a novel method. In case of processing polyolefins with an injection moulding machine it was found that there is adhesive wear between the check-ring and the flights of the screw tip of the non-return valve under certain circumstances. The temperature in that region was measured with an infrared temperature sensor. The existence of significant peaks of that signal was used as an indicator for an adhesive wear situation.

• 반도체디스플레이기술학회지
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• 제11권2호
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• pp.71-74
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• 2012

Uniformity of the wafer temperature is one of the important factors in etching process. Plasma, chucking force, backside helium pressure and the surface temperature of ESC(electrostatic chuck) affect the wafer temperature. ESC consists of several layers of structure. Each layer has own thermal resistance and the Si-adhesive layer has highest thermal resistance among them. In this work, the temperature distribution of ESC was analyzed by 3-D FEM with various defects and the thickness deviation of the Si-adhesive layer. The result with Si-adhesive layer with the low center thickness deviation shows modified temperature distribution of ESC surface.

• 접착 및 계면
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• 제3권1호
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• pp.9-12
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• 2002

In this paper, N,N-m-phenyenedimaleimide (m-PDM), Polyamide Resin (PI) and Metallic dimethacrylate etc. influencing the heat resistance of anaerobic adhesive has been studied, an anaerobic adhesive composition capable of post-cure expansion and $230^{\circ}C$ temperature resistance comprising a multifunctional methacrylate and m-PDM capable of effectuating expansion upon post-cure has been developed. A homogeneous mixture of a monomer and m-PDM are subjected to a first cure heat stage (Room Temperature) wherein a rigid partially-cured plastic is formed and a post-cure heat stage ($150^{\circ}C$) to effectuate permanent expansion of cured adhesive composition.

• Journal of Welding and Joining
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• 제10권4호
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• pp.181-189
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• 1992

The purpose of this investigation is to examine the effects of the strengthening treatments on the mechanical properties of the flame-sprayed titania ceramic coating layer. The strengthening treatments for flame sprayed specimens were carried out in 12 different conditions in vaccum furance. The mechanical properties such as microhardness, thermal shock resistance, adhesive strength and erosion resistance were tested for the sprayed specimens after strengthening treatments. And it was clear that the mechanical properties of coating layer were much improved by the strengthening treatments. The results obtained are summarized as follows; 1. It was shown that the metallurgical bond was formed between substrate and coating layer by the strengthening treatments and that thermal shock resistance and adhesive strength were remarkably raised. 2. Microhardness of coating lay was considerably increased by the strengthening treatments. 3. Erosion resistance and porosity of coating layer were slightly improved by the strengthening treatments.

• JSTS:Journal of Semiconductor Technology and Science
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• 제3권3호
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• pp.122-131
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• 2003

In this study, some characteristics of conductive and non-conductive adhesive inter-connections are derived, based on data from literature and own projects. Assembly of flip chip on flex is taken as a carrier. Potential failure mechanisms of adhesive interconnections reported in literature are reviewed. Some methods that can be used to evaluate the quality of adhesive interconnections and to evaluate their aging behavior are given. Possible finite element simulation approaches are introduced and the required critical materials properties are summarized. Response to temperature and moisture, resistance to reflow soldering and resistance to rapid change in temperature and humidity are elaborated. The effect of post cure during accelerated testing is discussed. This study shows that only a combined approach using finite element simulations, and use of appropriate experimental evaluation methods can result in revealing, understanding and quantifying the complex degradation mechanisms of adhesive interconnections during aging.