APPLICATION OF COATINGS MADE BY PLASMA SPRAY AND PVD METHODS FOR PROTECTION OF GRAPHITE MOULDS

The results of our research on the application of coatings for protecting industrial casting molds are presented. Tests were carried out on graphite molds with deposited Al2O3 coatings containing the addition of glassy carbon and with W/Zr/DLC coatings, both examined after the process of pouring molds with molten aluminum bronze. The coatings were applied by two different methods; i.e., plasma spraying in the case of Al2O3 + glassy carbon coating and PVD in the case of W/Zr/DLC coating. Reference tests were also conducted on graphite molds without coating. The use of protective coatings on graphite molds seems to be an effective solution. Studies have shown that coatings have good resistance during the casting process. The liquid metal sticking to the surface did not penetrate deep inside the graphite mold. The use of coating technology reduces the amount of downtime necessary to replace worn molds and increases the efficiency of the casting process.Application of coatings made by plasma spray and PVD methods for protection of graphite mould

SELECTION OF PROTECTIVE COATINGS OBTAINED BY PLASMA-SPRAYING METHOD FOR FOUNDRY INDUSTRY

This article presents results from the studies of protective coatings applied to industrial graphite molds used for the casting of non-ferrous metals. The selection of coatings was based on the results of measurements of surface wettability by liquid copper and microstructure examinations. The study involved industrial graphite molds with single-layer protective coatings of Al2O3 + 30%C and ZrO2-Y2O3 + 30%C as well as two-layer protective coatings of Al2O3 + 30%C /glassy carbon and ZrO2-Y2O3 + 30%C /glassy carbon

Struktura i własności warstw Cr3C2 uzyskanych metodą PVD oraz natryskiem termicznym : praca doktorska /

Recenzenci pracy: Borys Mikułowski, Jerzy Smolik.Praca doktorska. Akademia Górniczo-Hutnicza im. Stanisława Staszica (Kraków), 2012.Bibliogr. k. 137-145.Sposoby otrzymywania powłok metodami natrysku termicznego, metody natrysku plazmowego, płomieniowego, elektrycznego, łukowego, sposoby otrzymywania powłok metodami fizycznego osadzania z fazy gazowej PVD, charakterystyka metod fizycznego osadzania z fazy gazowej PVD, opis metody odparowania łukiem elektrycznym Arc PVD, charakterystyka metody odparowanie wiązką elektronów EB PVD, charakterystyka materiałów powłokowych, materiały stosowane na powłoki ochronne w metodach natrysku termicznego, w procesach fizycznego osadzania z fazy gazowej, rodzaje węglików chromu, zjawiska powierzchniowe na styku łączonych faz, mechanizmy powstawania powłok, ich struktura, powstawanie, struktura powłok w metodach natrysku termicznego, wytwarzanie, struktura powłok w metodach fizycznego osadzania z fazy gazowej, zastosowanie powłok otrzymanych metodą natrysku termicznego, metodami fizycznego osadzania z fazy gazowej PVD, wpływ parametrów procesu nanoszenia, charakterystyka stanu materiału wyjściowego na jakość otrzymanej powłok, wpływ parametrów geometrycznych, naprężeń na właściwości powłok, badania doświadczalne, metodyka badań, nanoszenia powłok technologią natrysku termicznego, technologiami fizycznego osadzania z fazy gazowej PVD, badania struktury, rentgenowska analiza fazowa, badanie składu chemicznego, mikrotwardości, wielkości ziarna powłok, gęstości, porowatości powłok, wyniki badań powłok otrzymanych technologiami natrysku plazmowego, struktura obserwowana techniką mikroskopii optycznej, badania struktur skaningową mikroskopią elektronową, transmisyjną mikroskopią elektronową, wyniki badań składu chemicznego, powłok otrzymanych technologiami natrysku płomieniowego naddźwiękowego z dużymi prędkościami HVOF, struktura obserwowana techniką mikroskopii optycznej, badania struktur skaningową mikroskopią elektronową, transmisyjną mikroskopią elektronową, wyniki badań rentgenowskiej analizy fazowej, własności powłok, pomiar mikrotwardości, ocena wielkości ziarna w powłokach otrzymanych metodami natrysku termicznego, badania gęstości, porowatości powłok, wyniki badań powłok otrzymanych technologią odparowania łukiem elektrycznym Arc PVD, rentgenowskiej analizy fazowej powłok, struktura obserwowana techniką mikroskopii optycznej, badania morfologii powierzchni z wykorzystaniem mikroskopii skaningowej, struktur transmisyjną mikroskopią elektronową, wyniki badań powłok otrzymanych technologią odparowania wiązką elektronów EB PVD, rentgenowskiej analizy fazowej powłok, struktura obserwowana techniką mikroskopii optycznej, badania morfologii powierzchni z wykorzystaniem mikroskopii skaningowej, porównawcza ocena uzyskanych wyników badań strukturalnyc

Investigation on Microstructure, Mechanical and Wear Properties of HVOF Sprayed Composite Coatings (WC–Co + CR) On Ductile Cast Iron

Recent work indicates that the high-velocity oxy-fuel (HVOF) thermal spraying WC–Co coatings have been used to enhance the wear resistance of various engineering components in a variety of industrial environments. In the present work, WC–Co powder, containing Cr particles in an amount of 10%, was deposited on ductile cast iron with the HVOF thermal spray coating technique. An investigation was conducted to determine the role of Cr particles in the WC–Co coating produced with the HVOF technique on microstructure, mechanical, and wear properties in a system of type: WC-Co coating/ductile cast iron. The microstructure of the HVOF-sprayed WC–Co + Cr coating was characterised by light microscopy, X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), and energy-dispersive X-ray spectroscopy (EDS). The analysis of the microstructure showed the formation of a coating with low porosity, compact structure, and good adhesion to the substrate with a typical lamellar structure composed of fine molten Cr particles and finely fragmented WC grains embedded in a Co matrix, reaching the size of nanocrystalline. The scratch test was applied for the analysis of the adhesion of coatings to the substrate. The erosion behaviour and mechanism of material removal was studied and discussed based on microstructural examinations. Moreover, the results were discussed in relation to the bending strength test, including cracks and delamination in the system of the WC–Co + Cr/ductile cast iron, as microhardness and erosion resistance of the coating. It was found that the addition of Cr particles to the WC–Co powder, which causes hardening of the binder phase is a key influence on increased mechanical and wear properties in the studied system. Additionally, due to the construction of nanostructured coatings, suitable proportion of hard and soft phases, the technique sprayed HVOF coatings have advantageous properties such as high density and good slurry erosion resistance

Zinc Recovery from Steelmaking Dust by Hydrometallurgical Methods

Hydrometallurgical recovery of zinc from electric arc furnace dust was investigated on a laboratory scale, using aqueous sodium hydroxide solution as a leaching agent. Special attention was paid to the effect of NaOH concentration, temperature and liquid/solid phase ratio on the zinc leachability. It was found that all tested factors increased the leachability, with the maximum efficiency of 88% obtained in a 6 M NaOH solution at a temperature of 80 °C and the liquid/solid phase ratio of 40. The test results confirmed the high selectivity of the zinc leaching agent. In spite of this, complete recovery of zinc from steelmaking dust has proved to be very difficult due to the occurrence of this element in the form of stable and sparingly soluble ZnFe2O4 ferrite. Purification of the solution by cementation and electrolysis gave zinc of purity 99.88% in powder form

The Impact of Plastic Deformation on the Microstructure and Tensile Strength of Haynes 282 Nickel Superalloy Produced by DMLS and Casting

The article presents the results of research on the influence of plastic deformation on the microstructure and tensile strength of Haynes 282 nickel superalloy produced by direct metal laser sintering (DMLS) and a conventional technique (casting). Samples were tested for dimensional accuracy using a 3D scanner. Then, the samples were subjected to plastic deformation by rolling. The microstructures of the DMLS and the as-cast samples were analysed using a scanning electron microscope. The strength properties of the samples were determined in a static tensile test. Microhardness measurements of the samples were also performed. Based on the analysis of the dimensional accuracy, it was found that the surface quality of the components produced by DMLS is dependent on the input parameters of the 3D printing process. Using the DMLS method, it is possible to produce Haynes 282 with a fine-crystalline microstructure containing dendrites. The fine-crystalline dendritic microstructure and low porosity showed very good tensile strength compared to the as-cast material. It was also found that the increase in the degree of plastic deformation of the as-cast Haynes 282 and the samples produced by the DMLS technique resulted in an increase in the strength of the tested samples, with reduced ductility