Premium
Analytical Electron Microscopic Studies of Doped Dicalcium Silicates
Author(s) -
CHAN CHINJONG,
KRIVEN WALTRAUD M.,
YOUNG J. FRANCIS
Publication year - 1988
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1988.tb06403.x
Subject(s) - dopant , amorphous solid , wollastonite , mineralogy , materials science , analytical chemistry (journal) , doping , stoichiometry , microstructure , scanning electron microscope , saturation (graph theory) , crystallography , chemistry , metallurgy , composite material , raw material , mathematics , optoelectronics , organic chemistry , chromatography , combinatorics
Dicalcium silicates having CaO/SiO 2 molar ratios of 1.8 to 2.2 were sintered at 1450°C for 90 min with or without small quantities of dopants (K 2 O or Al 2 O 3 ) and were air quenched. The microstructures of the fired samples were characterized using electron microscopy (SEM and TEM) and associated microanalytical techniques. There was no evidence for the existence of Ca 1.8 SiO 3.8 or Ca 2.2 SiO 4.2 . Amorphous grain‐boundary phases were observed between grains and as inclusions within the grains; the amounts decreased as CaO/SiO 2 ratios increased. The compositions of the amorphous phases were always rich in dopants and had a CaO/SiO 2 ratio close to that of wollastonite. High levels of Al 2 O 3 were observed to enter the β‐Ca 2 SiO 4 grains under lime‐rich conditions (CaO/SiO 2 = 2.2) up to a saturation level of about 3.0 wt%. Some additional crystalline phases were observed to form depending on stoichiometry and dopant level.