Application of sacrificial coatings and effect of composition on Al-Al3Ni ultrafine eutectic formation

This paper introduces an unconventional method designed for forming hypereutectic alloys via coating deposition onto the substrate surface and subsequent heat treatment of such systems. The coating was produced from 99.7 wt% nickel powder by means of high velocity oxyfuel (HVOF) spraying onto the surface of 99.999 wt% aluminium sheet. The specimens were manufactured immediately after the spraying. Specimens were heat-treated using a differential thermal analysis (DTA) apparatus up to a temperature of 900°C and then cooled down to the room temperature in an argon atmosphere with constant heating and cooling rates, under which the NiAl3 intermetallic phase formed within the initial substrate. Two different alloy microstructures consisting of a coarse eutectic and an ultrafine well-dispersed eutectic were produced. The formation processes and resultant microstructures were studied by means of differential thermal analysis, metallography, scanning electron microscopy, energy dispersive microanalysis, and image analysis techniques.Web of Science501363

Synthesis of wollastonite powder and manufacturing of porous scaffolds for multiple applications

Wollastonite (CaSiO3) is gaining attention due to its attractive properties, which can be used in a wide field of industries, i.e., thermal insulation; catalysis; filters and water purification; reinforcement phase in composites; and more recently, in orthopaedics. The additive manufacturing method has been used to process various materials in order to obtain diverse shaped-structures with controlled porosity. The aim of the present work is to establish an easy synthesis and processing of wollastonite powder to elaborate porous structures via robocasting technique. An injectable paste that serves as an ink was developed to build up cylindrical structures of 10 mm in diameter and 10 mm in height, using a tip of 410 μm. The cylinders were 3D-printed following two different arrangement patterns, named as honeycomb and rectilinear infills. In the same way, two pore sizes of 350 and 500 μm were produced. The final structures were evaluated in terms of their porosity, shape and size of pores by scanning electron microscopy and compression test. The purity of the wollastonite bodies was evaluated by X-ray diffraction. Moreover, preliminary studies were carried out on the final consolidated porous scaffolds showing its potential use in catalysis, water purification and/or orthopaedics

Application of sacrificial coatings and effect of composition on Al-Al3NI Ultrafine eutectic formation

This paper introduces an unconventional method designed for forming hypereutectic alloys via coating deposition onto the substrate surface and subsequent heat treatment of such systems. The coating was produced from 99.7 wt% nickel powder by means of high velocity oxyfuel (HVOF) spraying onto the surface of 99.999 wt% aluminium sheet. The specimens were manufactured immediately after the spraying. Specimens were heat-treated using a differential thermal analysis (DTA) apparatus up to a temperature of 900°C and then cooled down to the room temperature in an argon atmosphere with constant heating and cooling rates, under which the NiAl3 intermetallic phase formed within the initial substrate. Two different alloy microstructures consisting of a coarse eutectic and an ultrafine well-dispersed eutectic were produced. The formation processes and resultant microstructures were studied by means of differential thermal analysis, metallography, scanning electron microscopy, energy dispersive microanalysis, and image analysis techniques

Control of magnetic vortex states in FeGa microdisks : Experiments and micromagnetics

Magnetic vortices have been an interesting element in the past decades due to their flux-closure domain structures which can be stabilized at ground states in soft ferromagnetic microstructures. In this work, vortex states are shown to be nucleated and stabilized in FeGa and FeGa disks, which can be an upcoming candidate for applications in strain-induced electric field control of magnetic states owing to the high magnetostriction of the alloy. The magnetization reversal in the disks occurs by the formation of a vortex, double vortex or S-domain state. Micromagnetic simulations have been performed using the FeGa material parameters and the simulated magnetic states are in good agreement with the experimental results. The studies performed here can be essential for the use of FeGa alloy in low-power electronics