Mechanical properties of hot-pressed calcium hexaluminate ceramics

Chemical Preparation of the Binary Compounds in the Calcia‐Alumina System by Self‐Propagating Combustion Synthesis

“…An and Chan 14 studied the microstructural and mechanical properties of Al 2 O 3 -CA 6 ceramic composites manufactured by the reactive sintering of alumina with CaO or CaCO 3 mixtures heated at a peak temperature of 1650°C for 2 h. It has been noted in this study that the enhanced toughening behavior observed in the samples is mainly due to the crack-bridging mechanism provided by the in situ formation of the CA 6 platelets. The control of the sintered grain morphology 15 and the mechanical properties 16 of the CA 6 -containing ceramic composites have also been studied.…”

Microprobe fluorescence spectroscopy evaluation of stress fields developed along a propagating crack in an Al2O3/CaO 6Al2O3ceramic composite

“…A ceramic matrix composite comprising of alumina together with 15 vol% calcium hexaluminate (CaAl 12 O 19 or "CA6") was prepared via a chemical route and pressureless sintering, the CA6 phase growing in situ with an elongated structure.…”

“…Considering that the R 2 line is less sensitive to the (unknown) crystallographic orientation of individual grains 16 and also that the value was collected by averaging over a large number of randomly oriented grains, the error related to the unknown crystallographic orientation of individual Al 2 O 3 grains was estimated to be less than 10%. [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] A thorough assessment of the error involved for the in situ determination of local bridging stresses within polycrystalline ceramics has been given elsewhere. 5…”

“…[2][3][4][5] While the greatest increases in fracture toughness have been obtained through the incorporation of continuous fibers, the inclusion of platelet or needlelike grains that develop in situ during sintering/densification 6 has the advantage of reduced processing time and cost while still providing reasonable increase in toughness. The elongated morphology of CA6, when combined with its mechanical 11,12 and thermal expansion 13 properties, suggest it to be a promising in situ toughening agent. 7 While significant effort has been spent on improving the mechanical properties of continuous-fiber ceramic matrix composites such as carbon-carbon (C/C) and silicon carbide-silicon carbide (SiC/SiC), the phenomenon of brittle failure due to oxidation of the composite components or fiber/matrix interface has still not been fully addressed.…”

Thermal Insulation and Strength Characteristics of Refractory Incorporating Natural Silica

“…However, according to the standard [5], it appears that the value is still lower than the standard which must not be less than 9.00 Kg.cm -2 . On the other hand, the calcium hexaluminate,CA 6 exhibites the most good thermal properties of the calcium aluminate system with a melting point above 1850 °C [14][15][16][17]. Also, the Permanent Linear Change (PLC) values show decreasing trend with increasing cured time.…”