Direct‐Write Fabrication of Pb(Nb,Zr,Ti)O₃ Devices: Influence of Paste Rheology on Print Morphology and Component Properties

Abstract

Lead niobium zirconate titanate (PNZT) pastes with tailored rheological properties have been developed for direct-write fabrication of thick-film capacitor elements in highly integrated, multifunctional electroceramic devices. Such pastes exhibited pseudoplastic behavior with a low shear apparent viscosity of roughly 1 ؋ 10 6 cP. On aging, the degree of shear thinning and the low shear apparent viscosity decreased. Pastes prepared from as-received powders attained printable, steady-state viscosities of ϳ2 ؋ 10 5 cP after 50 days of aging. In contrast, pastes prepared from dispersant-coated powders showed no measurable rheological changes after 1 day of aging. Square elements were patterned on dense alumina substrates or Teflon sheets. Leveling behavior as a function of time for single line prints, and the resulting surface topographies of dried PNZT films were measured by laser profilometry. PNZT layers sintered at varying temperatures between 950°and 1050°C for 5 h in either air or a lead-rich atmosphere yielded porous microstructures as revealed by scanning electron microscopy (SEM). Such layers exhibited dielectric constants (K) of 1400 -1570 at 1 kHz with dissipation factors (D) of less than 4.1%.

Rheological Behaviors and Their Correlation with Printing Performance of Silver Paste for LTCC Tape

“…4 shows the variation of viscosity and shear rate of silver paste with different percentage of thinner. As we can see the trend exhibited by all the samples is generally similar to the work carried out by Bell et al, (1987) and Morissette et al, (2001) on the influence of paste rheology on print morphology and component properties. Sample 0% to 6% thinner the viscosity slightly shows decreasing trend.…”

Direct Ink Writing of 3D Functional Materials

“…[11] Several direct ink writing techniques have been introduced that are capable of patterning materials in three dimensions. They can be divided into filamentary-based approaches, such as robocasting [12,13] (or robotic deposition [4,7,14,15] ), micropen writing, [16] and fused deposition, [17,18] and droplet-based approaches, such as ink-jet printing, [19,20] and hot-melt printing [21] (see Fig. 1).…”

Powder‐Based Ceramic Meso‐ and Microscale Fabrication Processes

“…after deposition), freestanding structures of 250 lm thickness spanning several millimeters have been micropen deposited. [26] As first applications, Pb(Nb,Zr,Ti)O 3 pastes were deposited as thick-film capacitors, [27] and ZnO varistors written by this method were characterized and compared to standard ZnO varistors.…”