Lattice Parameter Changes of Leucite by Incorporation of Various Cations Substituted for Potassium.

Abstract

Leucite crystals having modified compositions from stoichiometry were prepared by the incorporation of Na+, Rb+, Cs+, Ca2+, Ba2+, and Sb3+ substituted for 5-50 at% of K+ in the leucite. The lattice parameters of the a-and c-axes of these tetragonal leucite were derived from the diffraction angles of (400) and (004) peaks due to tetragonal leucite, respectively. Both lattice parameters of the a-and c-axes of the leucites except Rb and Cs were slightly smaller than those of stoichiometric leucite. The lattice parameters of the a-axis of the leucites containing Rb and Cs were larger than those of stoichiometric leucite (p<0.01) and increased with the content of Rb and Cs. It was concluded that the crystal lattice of leucite was deformed by the incorporation of cations substituted for K and their variations mainly depend upon the kind of cation, namely ionic size and substitution site in the lattice.

Understanding the Behavior of Radioactive Cesium during the Incineration of Contaminated Municipal Solid Waste and Sewage Sludge by Thermodynamic Equilibrium Calculation

“…We compiled the updated data in a new database. We assumed that pollucite (CsAlSi 2 O 6 ) forms an ideal solid solution with leucite (KAlSi 2 O 6 ) because the two minerals form a single-phase crystalline solid through hydrothermal synthesis or calcination. , We also assumed that CsAlSiO 4 and KAlSiO 4 also form a solid solution at high temperatures. Table lists the selected databases of FactSage 7.0, and Table summarizes the estimated thermodynamic properties of Cs compounds.…”

Crescimento de trinca subcrítico em cerâmicas odontológicas: efeito do material (microestrutura) e do método de ensaio

“…Desse modo, a microestrutura das porcelanas é caracterizada por apresentar cristais de leucita (K 2 O.Al 2 O 3 .4SiO 2 ) envolvidos em uma matriz vítrea de silicato de alumínio (BAN et al, 1999;DENRY, 1996;).…”

Efeito da troca iônica nos parâmetros de Weibull, de crescimento subcrítico de trincas e no comportamento de curva R de uma porcelana odontológica

“…O aumento do volume molar resultante leva a um estado de compressão bidimensional devido à expansão da superfície da estrutura a qual é restrita pela porção subjacente do material. Embora os íons de césio (Cs) e rubídio (Rb) (15,60) possam ser empregados na realização da simples troca iônica, são os íons de potássio (K) os mais comumente utilizados para substituir os íons de sódio (Na) do material neste processo (1,39,55,61,62) . Estes apresentam um volume 35% inferior quando comparados aos íons de potássio (K) que são introduzidos no material (63) .…”