Kristalizacija i struktura lijevane A 390.0 legure iz taline zagrijane na povišenim temperaturama

The paper presents the research on the influence of melt overheating temperature on crystallization parameters and primary structure of cast AlSi17Cu5Mg (A390.0) alloy overheated to temperature: 820 °C, 880 °C, 940 °C and 1 000 °C. It was found that the degree of overheating influences the change of microstructure significantly and morphologies of primary silicon of the castings from Al-Si alloys. Research has shown that the overheating of the liquid metal bath is one of the methods of finding more applications of hypereutectic Al-Si system alloys without the addition of modifiers.Članak daje istraživanje utjecaja taline na parametre kristalizacije i primarne strukture lijevane legure AlSi17Cu5Mg (A 390.0) zagrijane na povišenim temperaturama: 820 °C, 880 °C, 940 °C i 1 000 °C. Utvrđeno je da stupanj utjecaja pregrijavanja mjenja značajnije mikrostrukturu silikata lijevanih Al-Si legura. Istraživanje ukazuje da pregrijavanje tekućeg metala je jedna od metoda pronalaženja veće primjene hipereutektičkih Al-Si legura bez dodataka modifikatora

A study on the process of fine-grained plumbiferous material agglomeration

In the paper, results of a study on the agglomeration process of fine-grained plumbiferous materials, belonging to basic resources for lead recovery, are presented. For the agglomeration tests, a laboratory drum granulator and a balling disc were utilized. The obtained granules were tested for compression strength with the use of a so-called Michaelis testing device as well as for drop strength, determined per the standards. The results allowed for evaluating the effects of the composition of the blend of materials subjected to agglomeration on the quality of obtained granules

Wastes from the coal-enrichment process as alternative reducers for lead smelting from lead-acid accmulator scrap

In the paper, results of the study on a possible utilization of coal-enrichment wastes as alternative reducers for lead smelting from acid-lead accumulator scrap are presented. For the experiments, the following alternative carboniferous reducers were selected: coal slurry, anthracite dust and coal soot. The investigations included both laboratoryscale experiments and semi-industrial tests in a rotary furnace. The findings allowed for a review of the effects of a sample type (loose material or material post a preliminary agglomeration process), loaded into the furnace, on a final process yield

Wastes from the coal-enrichment process as alternative reducers for lead smelting from lead-acid accmulator scrap

In the paper, results of the study on a possible utilization of coal-enrichment wastes as alternative reducers for lead smelting from acid-lead accumulator scrap are presented. For the experiments, the following alternative carboniferous reducers were selected: coal slurry, anthracite dust and coal soot. The investigations included both laboratoryscale experiments and semi-industrial tests in a rotary furnace. The findings allowed for a review of the effects of a sample type (loose material or material post a preliminary agglomeration process), loaded into the furnace, on a final process yield

Modifications of the chemical composition and microstructure of flash smelting copper slags in the process of their reduction

Blister copper smelting in a flash smelting furnace results in generation of slag that contains high amounts of copper, iron and lead. Most commonly, this material is subjected to reduction with coke in an electrical furnace. In the present paper, results of investigations on reduction of slag with another reducer, i.e. anthracite dust, are discussed. Each experimental slag was analysed for its microstructure, chemical composition and phase composition. Based on the results, a decopperisation level of the study material was estimated. It was shown that anthracite dust might be considered as an alternative for currently used reducers

Microstructure and properties of YSZ coatings prepared by plasma spray physical vapor deposition for biomedical application

This paper presents the study of microstructure and properties of 8 mol% yttrium stabilized zirconia coating fabricated by Plasma Spray Physical Vapor Deposition technique on commercial pure titanium. The coating was characterized by X-ray diffraction, high resolution scanning electron microscope, profilometer, nanoindentation and nanomachining tests. The X-ray phase analysis exhibit the tetragonal Zr0.935Y0.065O1.968, TiO and α-Ti phases. The Rietveld refinement technique were indicated the changes of crystal structure of the produced coatings. The characteristic structure of columns were observed in High Resolutions Scanning Electron Microscopy. Moreover, the obtained coating had various development of surfaces, thickness was equal to 3.1(1) μm and roughness 0.40(7) μm. Furthermore, the production coatings did not show microcracks, delamination and crumbing. The performed experiment encourages carried out us to tests for osseointegration

Mikrostruktura i właściwości mechaniczne stopu AlSsi17Cu5 po obróbce cieplnej

In the paper results of the microstructure and mechanical properties (HB, Rm and R0,2) of AlSi17Cu5 alloy, subjected by solution heat treatment (500ºC/6h/woda) and aging (200ºC/16h/piec) are presented. In next step the alloy was modified and heated significantly above the Tliq temperature (separately and together). It was found that the increase in the strength properties of the tested alloy after heat treatment compared to alloys without solution heat treatment and aging was due to precipitation hardening. The applied aging treatment of ingots (preceded by solution heat treatment), causes not only increase in concentration in α(Al) solid solution, but also a favorable change of the primary Si crystals morphology. During stereological measurements significant size reduction and change in the morphology of hypereutectic silicon crystals ware found. This effects can be further enhanced by overheating the alloy to a temperature of 920ºC and rapid cooling before casting of the alloy.W pracy przedstawiono wyniki badań mikrostruktury i właściwości mechanicznych (HB, R,m i R0,2) odlewów ze stopu AlSi17Cu5 poddanych przesycaniu (500ºC/6h/wrząca woda) i starzeniu (200ºC/16h/piec) po procesie modyfikowania i znacznego przegrzania powyżej temperatury Tliq. (oddzielnie oraz łącznie). Stwierdzono, że podwyższenie właściwości wytrzymałościowych badanego stopu po obróbce cieplnej w stosunku do odlewów bez przesycania i starzenia nastąpiło na skutek utwardzania wydzieleniowego. Zastosowany zabieg starzenia poprzedzony przesycaniem, wywołuje nie tylko wzrost stężenia w roztworze stałym α(Al), ale też korzystną zmianę morfologii pierwotnych kryształów krzemu. Na podstawie pomiarów parametrów stereologicznych stwierdzono istotne zmniejszenie i zmianę morfologii nadeutektycznych kryształów krzemu, co dodatkowo można zintensyfikować przegrzaniem stopu do temperatury 920ºC i szybkim chłodzeniem przed odlaniem