Zn-Al-Cu alloys are used as an alternative material for bronze, cast iron and aluminum alloys in bearings and as construction material. Advantageous results brings of their application for bearings exposed to high loads. One of the factors determining the possible applications of Zn-Al-Cu alloys is their resistance to electrochemical corrosion. In literature can be found information on the corrosion resistance of Zn-Al-Cu alloys. There have been no comprehensive studies on the influence of casting conditions and modifications of chemical composition on the structure and corrosion resistance. The purpose of the experiments was to determine the structure and corrosion resistance of cast Zn-40%Al-2%Cu alloy. The scope of the experiments included X-ray phase analysis, potentiodynamic and potentiostatic tests, surface condition examinations and alloy structure characterization both before and after corrosion. The Zn40Al2Cu alloy is characterized by a dendritic structure, consisting of solid solutions of Al, Zn-Al and Zn and the CuZn5 phase. A corrosive environment affects the structure of the subsurface zone of the Zn40Al2Cu alloy to a depth of 60 to 130 μm, where a decrease of zinc content and an increase of aluminum content are observed.

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Zn-Al-Cu alloys are characterized by advantageous set of functional quality futures: tribological, strength, corrosion. They are used as an alternative material for bronze, cast iron and aluminum alloys in bearings and as a structural material. Properties of Zn-Al-Cu can be improved by partial or total replacement of copper with silicon and addition of rare - earth elements. Previous studies of the current authors have shown a significant effect of cooling rate on the structure of the ZnAl22Cu3 alloy. The presence of pores and significant differences in porosity between samples slowly and fast cooled has been found. The aim of this study was to determine the effect of cooling conditions on the pore formation in ZnAl22Cu3 alloy. The article presents the structure of the slowly and fast cooled alloy. Structural examinations were carried out on samples taken from the top, center and bottom of the ingot. In order to determine the microstructure metallographic tests were carried out using optical microscope and electron scanning microscope. Through EDS X-ray spectrometry quantitative analysis of characteristic microareas was performed as well. In order to assess the morphological characteristics of the pore a computer program Met-Ilo developed in the Department of Materials Science, Silesian University of Technology has been used. Changes of the volume fraction and the average area on a flat cross section in particular areas of the ingot were analyzed quantitatively.

Zn-Al-Cu alloys are characterized by a number of beneficial properties that include good castability, good tribological properties and low energy input for forming the product. When compared to bronze, Zn-Al-Cu alloys have a lower density. Properties of Zn-Al-Cu can be improved by the partial or total replacement of copper with silicon and rare earth element additions. In the literature there are few studies on the effect of casting conditions and modifying the chemical composition through the introduction of alloy micro-additives on the alloy structure. The aim of this study was to determine the effect of casting conditions and silicon and rare earth element additions on the structure of Zn-22% Al-2%Cu alloy. The subjects examined were the unmodified alloy, the alloy with 1.5% Si and the alloy with 1.5% Si and rare earth elements (mich metal). Samples were cast in sand and graphite molds. The liquidus temperature for each of these examined samples was determined. Structure examinations were carried out in samples taken from the top, center and bottom of the ingot. In order to determine the microstructure of the examined structures metallographic examinations using an optical microscope and a scanning electron microscope with energy dispersive spectroscopy (EDS) capabilities, an X-ray microscope, was performed. Quantitive analysis on specific, characteristic microzones was performed based on the EDS X-ray spectroanalysis results.

The Microstructure of AnnealedGalfanCoating on Steel SubstrateThe commercially availableGalfancoating containing 5-7wt.% of Al deposited on the low carbon steel substrate by hot dipping has been examined with respect to the microstructure of the coating/substrate interface area. The application of several experimental techniques (SEM/EDS, XRD, TEM/AEM/EDS/ED) allowed demonstrating the two-phase structure of the alloy coating in non-treated, commercially availableGalfansamples: Zn-rich pre-eutectoidηphase grains are surrounded by lamellar eutectics ofβ-Al andη-Zn. The transition layer between the alloy coating and steel substrate with the considerably higher Al content (SEM/EDS, TEM/EDS) has been found in both non-treated and annealed samples (600°C/5 minutes). Only the monoclinic FeAl3Znxphase however was revealed in the annealed sample (TEM/electron diffraction) remaining uncertain the presence of the orthorhombic Fe2Al5Znxphase, reported by several authors.