Macroporous high-temperature insulators physical properties by in situ CA(6) formation: Does the calcium source matter?

Author(s)

Borges, O. H. ^{[1, 2]} ; Santos Junior, T. ^{[1, 2]} ; Oliveira, R. R. B. ^[2] ; Salvini, V. R. ^[3] ; Pandolfelli, V. C. ^{[1, 2]}

Affiliation

^[1] Univ Fed Sao Carlos, Grad Program Mat Sci & Engn, Sao Carlos - Brazil

^[2] Univ Fed Sao Carlos, Mat Engn Dept, FIRE Associate Lab, Mat Microstruct Engn Grp GEMM, Rodovia Washington Luis, Km 235, BR-13565905 Sao Carlos, SP - Brazil

^[3] Coll Technol FATEC, Jordao Borghetti St 480, BR-14160050 Sertaozinho, SP - Brazil

• Document type: Journal article
• Source: Journal of the European Ceramic Society; v. 40, n. 10, p. 3679-3686, AUG 2020.
• Web of Science Citations: 0

Abstract

Aiming the in situ formation of CA(6) (CaO center dot 6Al(2)O(3)) at alumina-based macroporous insulators, distinct Ca2+ sources and contents were used and their effect on some of the refractories properties were investigated. Adding CaCO3, Ca(OH)(2) or CaO resulted in the decrease of the onset strengthening temperature (T-S) and also of the linear shrinkage. However, a higher amount of Ca(OH)(2) and CaO could not be used because of their effect on reducing the insulator total porosity. The composition prepared with 12.9 wt% of CaCO3 was the most promising one, leading to an expansion of 0.81 % after firing at 1600 degrees C for 5 h, T-S of 680 degrees C and low thermal conductivity. These results point out the potential reduction of sintering temperatures and to the possibility of in situ firing the ceramic insulator. These features enable the development of a macroporous refractory composition with a higher thermal insulating effectiveness, which can help industries to decrease their energy demand. (AU)

• FAPESP's process: 18/07745-5 - Dimensional control of Macroporous ceramics by in situ CA6 formation
• Grantee: Otávio Henrique Borges
• Support Opportunities: Scholarships in Brazil - Master