CA(6)-based macroporous refractory thermal insulators containing mineralizing agents

Author(s)

Borges, O. H. ^{[1, 2]} ; Jr, T. Santos ; Salvini, V. R. ^[3] ; Pandolfelli, V. C. ^{[4, 5]}

Affiliation

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

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

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

^[4] Jr, Jr., T. Santos, Univ Fed Sao Carlos, Grad Program Mat Sci & Engn, Sao Carlos, SP - Brazil

^[5] Jr, Jr., T. Santos, Univ Fed Sao Carlos, Mat Microstruct Engn Grp GEMM, FIRE Associate Lab, Dept Mat Engn, Rodovia Washington Luis, Km 235, BR-13565905 Sao Carlos, SP - Brazil

• Document type: Journal article
• Source: Journal of the European Ceramic Society; v. 40, n. 15, p. 6141-6148, DEC 2020.
• Web of Science Citations: 0

Abstract

Aiming at reducing the temperature of CaO center dot 6Al(2)O(3) (CA6) formation, SiO2, ZnO, and TiO2 were evaluated as mineralizing agents in an Al2O3-CaCO3 based macroporous thermal insulator. For the concentrations tested (0.6 mol% to 2.8 mol%), SiO2 presented a small effect in the temperature of CA(6) formation. However, ZnO and TiO2 favoured full CA(6) generation at 1400 degrees C, 200 degrees C below the reference composition. All analysed systems, besides 2.8Si, showed high porosity ( 80 %), suitable mechanical strength and expansion after firing at 1600 degrees C for 5 h. Softening temperature evaluation highlighted that ZnO-and TiO2-containing compositions could be used at higher temperatures than the SiO2 ones. Thus, compositions containing 2.8 mol% of ZnO or TiO2 were evaluated according to their thermal conductivity (keff), showing lower keff than the reference composition. Therefore, using these mineralizing agents, which are easily available, may provide reductions in the energy input to produce CA(6)-containing thermal insulators and benefits to all other required properties. (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