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Silver Matrix Composites - Structure and Properties

Wieczorek J., Oleksiak B., Łabaj J., Węcki B., Mańka M.

Archives of Metallurgy and Materials

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2016

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Vol. 61, iss. 1

323--328

EN

Phase compositions of composite materials determine their performance as well as physical and mechanical properties. Depending on the type of applied matrix and the kind, amount and morphology of the matrix reinforcement, it is possible to shape the material properties so that they meet specific operational requirements. In the paper, results of investigations on silver alloy matrix composites reinforced with ceramic particles are presented. The investigations enabled evaluation of hardness, tribological and mechanical properties as well as the structure of produced materials. The matrix of composite material was an alloy of silver and aluminium, magnesium and silicon. As the reinforcing phase, 20-60 μm ceramic particles (SiC, SiO2, Al2O3 and Cs) were applied. The volume fraction of the reinforcing phase in the composites was 10%. The composites were produced using the liquid phase (casting) technology, followed by plastic work (the KOBO method). The mechanical and tribological properties were analysed for plastic work-subjected composites. The mechanical properties were assessed based on a static tensile and hardness tests. The tribological properties were investigated under dry sliding conditions. The analysis of results led to determination of effects of the composite production technology on their performance. Moreover, a relationship between the type of reinforcing phase and the mechanical and tribological properties was established.

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Synthesis of Ag-ZnO composites via ball milling and hot pressing processes

Ardestani M., Zakeri M, Nayyeri M J, Babollhavaejie M R

Materials Science Poland

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2014

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Vol. 32, No. 1

121--125

EN

Ag – 8 wt. % ZnO composites were synthesized by ball milling, heat treating and hot pressing of silver and zinc oxide powder mixtures. The crystalline size and microstrain of the milled powders before and after heat treatment were determined by Debye-Scherrer andWilliamson-Hall methods. It was shown that heat treatment resulted in decrease of microstrain and increase in the crystallite size of the milled powders. The effect of uniaxial pressure magnitude and duration of hot pressing at 550 °C on the final density of the powder compacts were investigated. The results showed that both plastic flow and atomic diffusion mechanisms affected densification of the composite powders during the hot pressing process. However, the latter one had more effective role on the density of the hot-pressed samples. The synthesized composites showed homogenous microstructure with relatively high density and hardness.

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Tribological properties of silver matrix composites

Wieczorek J., Śleziona J.

Archives of Foundry Engineering

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2007

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Vol. 7, iss. 2

181-184

EN

Silver, silver alloys, as well as matrix based composites have been well known and applied in the electrotechnical and electronics industry for several decades. For many applications in electrotechnology, including electric contacts and brushes, unreinforced sliver alloys do not meet the requirements concerning mainly durability and wear resistance, first of all to tribological and electroerosive wear. These wear processes may be prevented by introducing to silver reinforcement particles. It can be stated, comparing recorded friction coefficient values of all investigated materials, that in the dry sliding conditions the ceramic particles introduction into matrix has its effect on the friction coefficient value lowering. If metallic particles are used as reinforcement, and in the investigated composites iron particles were used, the friction coefficient increases its value comparing to the matrix.