Aluminium matrix composite with low value of coefficient of friction
Jerzy Myalski Politechnika Śląska, Katedra Technologii Stopów Metali i Kompozytów, ul. Krasińskiego 8, 40-019 Katowice
Annals 2 No. 4, 2002 pages 191-194
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abstract Durability and reliability of abrasive system depends on of the construction of friction system and physicochemical properties of the applied materials. These characteristics may by obtain choosing optimal composition of the friction materials e.g. binding agent, modificators, and fillers. One of these materials is amorphous carbon, which increase thermal stability of friction materials. Hard particles of amorphous carbon may change wear and coefficient of friction parameters. Composite was made in mixing technology glass like carbon particles in liquid metal matrix. Before mixing in liquid metal, carbon particles were been prepared in chemical process of galvanisation. Ni coating layer on the particles has about 1÷2 µm thickness. This coating protected carbon particle before thermal destruction in high temperature and assures good distribution particles in matrix (Fig. 1a). On the boundary surface was obtained good bonding between components (Fig. 1b). In this paper the results of investigation of the influence of glass carbon in metal matrix composite, their tribological properties have been shown. Investigation has been led in pin-on-disc system on the tribological tester T-01 M for velocity v = 0.1÷1.0 m/s and load 20, 30, 40 and 50 N in friction distance 200m (Figs 2 and 3). The investigation has been led in dry and liquid friction. Addition 10% glass like carbon into MMC’s friction materials leads to decreasing coefficient of friction and increasing abrasive wear also. Decreasing of friction coefficient, in investigating composite was about 3÷4 times less then in composite materials containing SiC or Al2O3 particles e.g. Duralcan composites. The results of investigation let to design a construction, which possible apply to the modification of friction materials. The glass like carbon may be apply to the producing of new friction materials, for example brake discs and pistons.