Processing and properties of textured potassium strontium niobate (KSr₂Nb₅O₁₅) ceramic fibers-effect of texture on the electrical properties

Abstract

Textured ceramic fibers were fabricated from the tungsten-bronze-type piezoelectric (KSr2Nb5O15) . Development of crystallographic texture was evaluated through rocking curve analysis and a texture with Lotgering factor of 0.97 was achieved. 1-3 piezocomposites were prepared from the textured fibers and their electrical properties were evaluated. Highly enhanced properties that are 2 to 3 times higher than the random case were observed with increasing texture fraction with P(r) and d33 reaching 20 μC/cm(2) and 75 pC/N, respectively.

Enhancement of electrical properties in the ternary PMN–PT–PZ through compositional variation, crystallographic texture, and quenching

“…[5][6][7][8][9] This is usually accomplished using a combination of tape casting and templated grain growth processes. In the initial step, single crystalline template particles with anisometric morphologies such as plate-like 6,7 or needle-like 8,9 morphologies are aligned during the tape casting process through the shear stresses that arise between the doctor blade and the substrate. This is followed by a high-temperature annealing step called the templated grain growth (TGG) where the green body densifies, and the oriented template grains grow at the expense of fine-grained matrix powder.…”

“…4 However, development of a crystallographic texture in a polycrystalline ceramic, thereby achieving anisotropic properties that are comparable to that of single crystal in certain directions is a highly viable and valid approach to increase electrical properties. [5][6][7][8][9] This is usually accomplished using a combination of tape casting and templated grain growth processes. In the initial step, single crystalline template particles with anisometric morphologies such as plate-like 6,7 or needle-like 8,9 morphologies are aligned during the tape casting process through the shear stresses that arise between the doctor blade and the substrate.…”

Processing and Properties of Textured Potassium Sodium Niobate [K,Na]NbO3 Ceramic Ribbons by Alginate Gelation Method

“…In light of these drawbacks, a novel technique was developed to produce thick ribbons and fibers with crystallographic texture continuously using the alginate gelation method and templated grain growth method together, and to fabricate bulk ceramics with crystallographic texture through green packing of numerous ribbons or fibers together. This technique has the following merits: The shear stresses are effective in a longer region for a longer time to obtain an effective grain orientation in larger cross‐sections, as shown in Fig.…”

“…Development of texture using the combination of alginate gelation and templated grain growth is a patent pending drawing process that involves extrusion and instant gelation of a sodium alginate containing water‐based slurry and was first reported by our group on fabrication of textured KSr 2 Nb 5 O 15 piezoelectric ceramic fibers. Sodium alginate is a natural linear copolymer that is derived from brown kelp .…”

“…The template particles align along the ribbon drawing direction, as shown in Fig. (b) as a result of shear stress arising during the extrusion process and this preferred alignment is frozen in place and retained through the gelation process . Compared to other synthetic monomers that are used in coagulation of ceramic suspensions such as acrylamide, or thermoplastic polymers that are used in conventional extrusion of ceramic articles, alginate is a nontoxic natural polymer.…”