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2 Archives of Materials Science and Engineering

2 2021

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Influence of orientation of zones of higher hardness of composite layers on their resistance to wear

Peremitko V.V., Kolomoyets I.V.

Archives of Materials Science and Engineering

2021

Vol. 110, nr 2

59--71

Purpose: Experimentally substantiate the influence of the orientation of zones of higher hardness on the wear mechanism of contact surfaces. Design/methodology/approach: Forming of variable composition within the working surfaces of parts is a common way to solve the problem of uneven wear. The tests were aimed at determining the characteristics of the layers surfaced with the orientation of the zones of high hardness. For this different tests and measurements were done. Before the test, samples of 45 steel were surfaced with a preliminary application of titanium carbide paste. Findings: As a result of researches it was found that different ways of the orientation of zones of higher hardness have different influences on the characteristics of a surface. The main conclusion is that the transverse orientation of such zones helps to increase the wear resistance of the surface and to save its original relief. Research limitations/implications: The roughness, wear resistance, zonal hardness, and relief of layers surfaced with the orientation of zones of higher hardness were studied. Practical implications: The results obtained are useful in the field of rolling production and mechanical engineering to avoid the uneven wear of parts and as a result to extend the term of their exploitation. Originality/value: In this paper the model concepts of wear process of surfaces with variable composition and measurements of characteristics of surface considering its local hardening are proposed.

Effect of milling time on microstructure of cobalt ferrites synthesized by mechanical alloying

Tomiczek Anna E.

Archives of Materials Science and Engineering

2021

Vol. 111, nr 1

5--13

Purpose: of this paper is to determine the effect of manufacturing conditions, especially milling time, on the microstructure and phase composition of CoFe2O4 cobalt ferrite. Design/methodology/approach: Cobalt ferrite (CoFe2O4) has been synthesised from a stoichiometric mixture of CoCo3 and α-Fe2O3 powders in a high energy planetary mill. Annealing at 1000°C for 6 hours after milling was used to improve the solid-state reaction. Calcinated samples were analysed by X-ray diffraction (XRD), and transmission electron microscopy (TEM). The relationship between the milling time of powders, their microstructure, as well as their properties were evaluated. Particles size distribution and scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDX) examination were also made. Findings: CoFe2O4 ferrites were successfully synthesized by mechanical alloying of α-Fe2O3 and CoCO3 powders. The powder particles had undergone morphological changes with the increasing milling time. However, the milling time does not affect the ferrite formation rate. It is expected that the improvement of fabrication parameters can further enhance the properties of cobalt ferrite presented in this work. Research limitations/implications: Contribute to research on the structure and properties of cobalt ferrites manufactured by mechanical alloying. Practical implications: The reactive milling and subsequently annealing is an efficient route to synthesise cobalt ferrite powder. However, using steel milling equipment risks powder contamination with iron and chromium from the vials and balls. Originality/value: The results of the experimental research of the developed ferrite materials served as the basis for determining material properties and for further investigation.