Struktura i właściwości cienkich warstw międzymetalicznych Al-Cu-Fe nanoszonych metodą wieloźródłowego rozpylania magnetronowego

Thin films of Al-Cu-Fe type have been deposited by means of multisource, DC magnetron sputtering from elemental, metallic targets. The composition of films, studied by the EDS method, has been chosen which is close to the one corresponding to the icosahedral quasicrystalline phase [psi]-Al(62.5)Cu(25.0)Fe(12.5) X-ray diffraction studies of films deposited at 400°C on steel substrates revealed that the cubic [beta]-Al(Cu,Fe) phase is a dominant one. SEM and TEM techniques have been used for the surface and cross section characterisation of deposits. Prolonged post annealing of these coatings led to inter-diffusion of components between the steel substrate and the coating. It leads to the change of the phase composition of the coating and the iron-rich monoclinic [lambda]-Al3Fe1-xCux phase emerges in the film. The preliminary studies of microhardness and tribological behaviour show that the film microhardness reaches a local maximum of about 8.5 GPa for the chemical composition close to the one of the quasicrystalline phase. However, the presence of this phase in studied films has not been proven yet. The friction coefficient values, measured against alumina in ball on disc geometry, oscillate around 0.65 - the value lower than that observed for uncoated 4H13 steel.Cienkie warstwy trójskładnikowe Al-Cu-Fe nanoszono metodą stałoprądowego, wieloźródłowego rozpylania magnetronowego z katod metalicznych. Skład warstw, kontrolowany metodą spektroskopii energodyspersyjnej (EDS) był zbliżony do składu quasi-krystalicznej fazy [psi]-Al(62.5)Cu(25.0)Fe(12.5) o symetrii dwudziestościanu. Struktura warstw nanoszonych przy temperaturze podłoża równej 400°C odpowiadała kubicznej fazie [beta]-Al(Cu,Fe). Morfologię powierzchni warstw oraz ich strukturę badano odpowiednio metodami elektronowej mikroskopii skaningowej (SEM) oraz transmisyjnej mikroskopii elektronuzji składniowej (TEM). Długotrwałe wygrzewanie badanych warstw, nanoszonych na stali prowadzi do dyfuzji żelaza w głąb warstwy, co skutkuje pojawieniem się bogatej w żelazo jednoskośnej fazy [lambda]-Al3Fe1-xCux. Wstępne badania mikrotwardości wskazują na szerokie maksimum na poziomie 8,5 GPa dla warstw o składzie zbliżonym do składu fazy quasi-krystalicznej. Obecność wydzieleń tej fazy w badanych warstwach nie została jeszcze jednoznacznie potwierdzona. Współczynnik tarcia, mierzony względem ceramiki alundowej w układzie kula--płaszczyzna, oscyluje wokół wartości 0,65 i jest niższy niż obserwowany dla niepokrytej stali 4H13

Comparison of ultrasonic and other atomization methods in metal powder production

Purpose The results showed that the UA powder has a finer average particle size with a narrower statistical distribution of particles than those made by the GA method. Because the UA powder has a higher sphericity and lower porosity, Generally, UA offers better-quality powders in terms of properties such as higher tap density, better flowability and low oxygen content. Design/methodology/approach Ultrasonic atomization (UA) with melting raw material by an electric arc. Characterisation of the powders: particle size distribution (PSD), density, and flowability were carried out. Other parameters, such as microstructure, deviation in the chemical composition and powder surface morphology, were also investigated. Findings The results showed that the UA powder has a finer average particle size with a narrower statistical distribution of particles than those made by the GA method. Because the UA powder has a higher sphericity and lower porosity, Generally, UA offers better-quality powders in terms of properties such as higher tap density, better flowability and low oxygen content. Research limitations/implications As an example of semi-industrial scale application of the UA system, the Ti6Al4V and TiAl powders were produced after remelting the wire. The UA system is commercially available for processing any metallic material. Practical implications The test campaign results showed that the Ti6Al4V powder produced by the ultrasonic atomisation has a similar or better quality as those available from large-scale gas atomisation plants. Originality/value The new method of UA powder production was analysed in terms of key powder parameters. The properties of the titanium-based powder produced this way were analysed with a view to future applications