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Friction films analysis and tribological properties of composite antifriction self-lubricating material based on nickel alloy

Roszak Maciej Robert, Kurzawa Adam, Roik Tetiana, Gavrysh Oleg, Vitsiuk Iulia, Barsan Narcis, Pyka Dariusz, Bocian Mirosław, Jamroziak Krzysztof

Materials Science Poland

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2023

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Vol. 41, No. 3

1--17

EN

This article analyzes the composition and distribution of chemical elements in friction films and their effect on the tribological properties of the self-lubricating, high-temperature antifriction composite based on EP975 powder nickel alloy with CaF2 solid lubricant. Analysis of the chemical elements by energy-dispersive spectroscopy (EDS) showed their uniform distribution, on both the composite’s surface and the counterface’s surface. The alloying elements’ uniform distribution leads to a uniform distribution of the corresponding phases and structural elements in the antifriction film. This ensures high tribological properties at high temperatures. Analysis of the material’s tribological properties, by means of metallographic and micro-X-ray research confirmed the correctness of the technology for producing the composite. Solid lubricant CaF2, alloying elements, and their corresponding phases form the continuous antiscoring film. The film influences the antifriction properties formation during the friction process and provides a self-lubricating mode under the action of high temperature and oxygen. Antiscoring, self-lubricating CaF2 films minimize wear of the friction pairs and defend the contact surfaces against intensive wear. The dense antifriction films have smooth microtopography, which stabilizes the high-temperature friction unit operation. Thus, the self-lubrication mode is realized for a long exploitation time. Tribological properties analysis allowed us to determine the ranges of rational exploitation modes for the material being studied: a load up to 5.0 MPa, a slide speed from 0.3 to 1.0 m/s, a temperature up to 800°C, in the air. The results obtained opened the opportunity to control the antifriction film formation and the composite’s tribological properties by the choice of the initial ingredients while taking into account the operating conditions.

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Tribosynthesis of friction films and their influence on the functional properties of copper-based antifriction composites for printing machines

Olaleye Kayode, Roik Tetiana, Kurzawa Adam, Gavrysh Oleg, Pyka Dariusz, Bocian Mirosław, Jamroziak Krzysztof

Materials Science Poland

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2022

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Vol. 40, No. 4

147--157

EN

This article is devoted to research of the tribosynthesis mechanism of antifriction films and their influence on the functional properties of antifriction composites based on copper alloyed with nickel and molybdenum with the CaF2 solid lubricant additions for operation at rotation speeds of 3,000–7,000 rph and increased loads of 3.0–5.0 MPa in air. Studies have shown that antifriction films are complex, dynamically changing formations on the surfaces of the composite and counterface, developing according to the bifurcation mechanism. The antifriction layer is decisive in the formation of the friction pair's tribological high-level properties, which provide the self-lubrication mode of the friction unit. The formation and permanent presence of the anti-seize film is associated with a balanced wear rate of the film and its constant formation again on these worn areas at rotation speeds of up to 7,000 rph and loads of up to 5.0 MPa. Due to the steady self-lubrication mechanism, the copper-based composite has significant advantages over cast bronze CuSn5ZnPb, which can only work with liquid lubrication in the friction units of printing machines. The performed studies make it possible to choose rational modes for operation of new high-speed antifriction Cu-composites based on the friction films analysis, predicting their high functional properties.

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Case study of accelerated wear of brake discs made of grey cast iron characterized by increased thermal stability

Zemlik Martyna, Dziubek Mateusz, Pyka Dariusz, Konat Łukasz, Grygier Dominika

Combustion Engines

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2022

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R. 61, nr 3

45--49

EN

In this paper, the subject of the analysis is Rotinger High Performance brake disc, characterized by increased thermal resistance, which is a result of adequate design and material solutions. However, despite declared performance, the analyzed discs suffered accelerated wear over a period of about 20 months. The aim of this study was to assess the causes of the disc failure. As a result, it was showed that the applied material solution still does not differ from standard ones. According to the authors of this paper, an appropriate procedure to improve resistance to thermal fatigue is, among others, changing the shape of graphite precipitates from flake to spheroidal.

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Experimental analysis of puncture resistance of aramid laminates on styrene-butadiene-styrene and epoxy resin matrix for ballistic applications

Pach Joanna, Mayer Paulina, Jamroziak Krzysztof, Polak Sławomir, Pyka Dariusz

Archives of Civil and Mechanical Engineering

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2019

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Vol. 19, no. 4

1327--1337

EN

The work aimed to evaluate the influence of the type of matrix and the number of reinforcement layers on the puncture of aramid laminates. The samples were examined under laboratory conditions and in ballistic tests. Two series of aramid laminates were produced with different types of the polymer matrix. The epoxy resin (EP) and the styrene-butadiene-styrene (SBS) copolymer were used as the matrix. For comparison, a puncture test was performed for the fabric with the same number of layers in contrast to the laminates. Laboratory tests were carried out using the InstronDynatup 9250 HV drop hammer. The results obtained during the laboratory and ballistic examinations were compared. The samples were fired with a 9 - 19 mm Parabellum projectile. Research into the low-velocity range have shown that SBS laminates absorb impact energy more effectively than epoxy resin ones, but they are similar to fabrics without a polymer matrix. The results of ballistic tests are divergent and indicate that unbound materials are more efficient at absorbing energy than laminates. The reason for this is the different damage mechanisms.