Synthesis and Consolidation of BaAl₂Si₂O₈:Eu: Development of an Integrated Process for Luminescent Smart Ceramic Materials

Abstract

A novel, integrated, fast, and inexpensive process for the preparation of dense Ba(1−x)EuxAl2Si2O8 thin ceramic specimens for damage sensor applications is reported. The processing approach involves a combination of combustion synthesis for the preparation of the powders and spark plasma sintering (SPS) for the consolidation of the specimens to densities close to 100% of relative density. The synthesis of the porous powders by combustion resulted in particle (agglomerate) sizes that were on average 421 nm, as determined from dynamic light scattering, and in the almost complete reduction of the initial Eu3+ activators to Eu2+. The powders densified to grain sizes of around 250 nm due to a collapse of the porous powder structure and minimal grain growth during SPS. Thermal treatment of the powders and sintered specimens improved the intensity of the emissions at 373 and 745 nm and diminished the emission at 485 nm. The luminescence phenomena from the specimens were a result of two mechanisms: (1) the removal of strain in the lattice due to thermal treatment, and (2) a charge transfer mechanism between Eu2+ and Eu3+.

Mechanisms of pore formation in high-temperature carbides: Case study of TaC prepared by spark plasma sintering

“…The temperature read by both pyrometers was recorded at 1 s intervals. More details and specific capabilities of the spark plasma sintering technique are discussed elsewhere [60][61][62][63][64]. After sintering, samples were fractured, and the specimens imaged with a scanning electron microscope (FEIe Quanta 200F, FEI Company, Hillsboro, OR).…”

Analysis of Particle and Crystallite Size in Tungsten Nanopowder Synthesis

“…First, 50 mL of deionized water were poured in a beaker and a few drops of HCl were added to maintain the pH of the solution at approximately 1. This beaker was placed in a glove box and 4.9571 g of WCl 6 were added to prepare a solution of WCl 6 (solution A). Immediately after the addition of the WCl 6 , a few white fumes were observed being released from the beaker.…”

“…Indeed, it has been found that for some materials, the particle (i.e., agglomerate) size of powders tends to define the final grain size of the dense compact under typical SPS conditions. [5,6] Thus, characterizing the crystallite size of a powder from X-ray diffraction or transmission electron microscopy is necessary, but not sufficient, in order to determine the sintering behavior of a powder and the final grain size after completion of sintering.…”

Mechanical Properties of an Fe‐Based SAM2×5‐630 Metallic Glass Matrix Composite with Tungsten Particle Additions

“…Additional details on the SPS process can be found elsewhere. [21][22][23][24][25] Phase development/devitrification of the samples was characterized by X-ray diffraction (Ultima IV, Rigaku, Japan) using CuKα radiation, a step size of 0.02 degrees 2θ, a count time of 1 s, and scanning from 20 to 80 degrees 2θ. Densities of the samples were evaluated by the Archimedes method using a Mettler Toledo Density Kit (Mettler Toledo, Columbus, OH).…”