Vacuum-sintered stainless steel porous supports for inkjet printing of functional SOFC coatings

Abstract

Porous metal supports for SOFC applications were produced via conventional powder metallurgy routes-tape casting and high-pressure injection moulding. The supports were sintered in vacuum at different vacuum levels and temperatures. Commercially accessible low-cost stainless steel 430L powder was chosen as source material. The relations between the vacuum sintering temperature and the supports properties were studied. The density and the open porosity distribution of sintered supports were determined by Archimedes' method, Optical Image Analysis and Hg-porosimetry. The microstructure and the stainless steel grain surface composition evolution were investigated by scanning electron microscope and energy dispersive X-ray spectrometry. direct ceramic inkjet printing (DCIJP) was employed as coating technology for depositing anode (NiO/GDC) and electrolyte GDC coatings. Suspension anode and electrolyte inks were developed in-house and the printing procedure was optimized to produce uniform coatings with thicknesses below 15 lm. The analyses confirmed that the as-produced substrates were suitable to support DCIJP deposited SOFC functional coatings.

Metal particle compaction during drop-substrate impact for inkjet printing and drop-casting processes

“…[1][2][3][4] Typically, these layers can be obtained by coating (pouring, spraying, casting, or smearing ink over the surface) or by printing (i.e., the ink layer is transferred from a stamp by a reverse action) metal based conductive inks onto desired substrates. [5][6][7][8] Dropcasting and inkjet printing ( Figure 1) are two technical processes that can be implemented independently (or in-series) in roll-to-roll manufacturing processes for coatings or patterned conductive layers without or with minimum substrate alteration. [4][5][6][7][8] Experimentally, ink drop-casting can be performed with a simple equipment (Figure 1(a)), but a good horizontal leveling of the substrate is essential.…”

“…[5][6][7][8] Dropcasting and inkjet printing ( Figure 1) are two technical processes that can be implemented independently (or in-series) in roll-to-roll manufacturing processes for coatings or patterned conductive layers without or with minimum substrate alteration. [4][5][6][7][8] Experimentally, ink drop-casting can be performed with a simple equipment (Figure 1(a)), but a good horizontal leveling of the substrate is essential. 5 The ink can be cast onto the substrate as isolated drops (Figure 1(c)) or as continuous liquid films that are further cured (or dried) at room or elevated temperature.…”

“…The desired patterned or continuous layer is then created with minimal or no influence exerted onto the substrate. [3][4][5][6][7][8] Typically, the common commercial inkjet printers utilizing the DOD technology are based on thermal, piezoelectric, or acoustic heads for droplet generation. [6][7][8] In a classical DOD printing configuration, an electrical signal excites a thermal or a piezoelectric element that induces a transient pressure pulse in the ink reservoir.…”

“…6,8 An alternative is represented by the electromagnetically (EM) actuated printing heads that minimize ink heating and reduce the complexity of the printing procedures. 3,4,7 In this configuration, the nozzle of the printing head has a fixed aperture size. A compressed-air flow provides a constant pressure allowing the drops production as a solenoid driven plunger opens and closes the nozzle orifice.…”

“…A compressed-air flow provides a constant pressure allowing the drops production as a solenoid driven plunger opens and closes the nozzle orifice. 3,4,7 The size of the jetted drops can be controlled by varying the pressure, the opening time, and/or the rheological properties of the ink. In the EM-DOD printing configuration, the movement of either the nozzle or the substrate is allowed, where the relative positions of the printing head and substrate are accurately adjusted using a controlled X-Y stage (see Sec.…”