SEARCH RESULT

Electrical contact materials are used in many applications, such as contactors, electrical switches, voltage regulators, circuit breakers, arcing tips, switch gears and relays. [1]. Silver is most widely used material for electric contact materials. Since silver exhibits the highest electrical and thermal conductivities among all the metals [2]. However, electrical contact materials have some disadvantages. Therefore, silver has limited life cycle for electric contact system [3]. Graphene has extraordinary mechanical, thermal and electrical properties as well as high surface area; which allows the graphene to be a good alternative reinforcement material for composites [4]. Electroless nanocomposite coating techniques have been widely used to prepare the composite coatings. As the advancement of electroless powder coatings, in which particles are used as reinforcing phase and the coated metal as a matrix [5]. For this reason, graphene reinforcement silver metal matrix nanocomposite was combined by electroless deposition for high current and long cycle electrical contact materials coatings. Graphene reinforced silver was deposited on to copper substrate with graphene inclusive aqueous silver baths by electroless deposition method. Because of the uniform coating capability onto various substrate, electroless coating method was selected. Graphene reinforced silver electroless autocatalytic deposition bath was made by combining two separate baths. One was a silver ion solution, while the other was a reducing agent solution. Composition of baths denoted them as A and B, respectively. A: 80 g/l Silver nitrate, 60g/l saturated ammonia solution and water. B: 432 g/l Rochelle salt,30g/l Epsom salt and water. Various amount of graphene was added to bath A: respectively 0.5, 1.0, 2.0, 4 g/l. Graphene was functionalized with a mixture of H2SO4 and HNO3 acids solutions before added to bath for homogeneous distribution into the matrix and good bonding with silver. Deposited layers surface structure was investigated with Scanning electron microscope(SEM). Also, graphene distribution into composite layer was investigated with Energy-dispersive X-ray spectroscopy (EDX). Amount of graphene effects on phase structure and grain size was achieved with X-Ray diffraction(XRD) method. Mechanical properties of deposited layers were detected with micro hardness test methods. Highest micro hardness value and most homogenous structure was achieved with 1 g/l graphene addition to silver bath. When the added 0.5 gr/l graphene inhomogeneous distribution and low hardness value was detected. Over the 1 g/l graphene addition caused graphene agglomeration area into nano composite structure. This agglomeration was decreased mechanical properties of composite layer.

International Symposium on Light Alloys and Composite Materials
UHAKS

Ece GÜRCAN Ramazan Karslıoğlu Hasan Okuyucu

The combination of CNT-Silver nanocomposite coatings are showed that significant improvements are demonstrated in the mechanical properties, phase and structural analyses, and surface images of CNT-Silver nanocomposite coatings. Carbon nanotubes (CNTs) have emerged as a novel material because of their unique properties such as being 10 to 100 times stronger than steel, high strength to weight ratio, elastic moduli as high as 1 TPa and electrical current carrying capacity 1000 times that of pure copper, and high thermal conductivity [1]. CNT reinforcement silver nanocomposites have increased value of hardness than pure silver coatings and improved the resistance of wear [2- 4]. The hardness values and surface roughness of the composite coatings are gradually increased with addition of carbon nanotubes content. Carbon nanotubes (CNT) reinforcement silver nanocomposite coatings have been obtained on copper with electrodeposition method. Effect of amount of MWCNT on microstructure and mechanical performance was investigated. Produced composite structure were investigated with scanning electron microscopy (SEM) and X-ray diffraction (XRD). Mechanical properties were detected with Vickers microhardness test method. Highest mechanical properties were achieved with 1 g/l MWCNT.

International Symposium on Light Alloys and Composite Materials
UHAKS

Fatma Taştekin Ece GÜRCAN Ramazan Karslıoğlu Hasan Okuyucu