Second-phase evolution and densification behavior of AlN with CaO–Y2O3–C multicomponent additive system

Autor: Humberto Naoyuki Yoshimura, André Luiz Molisani, Hélio Goldenstein
Rok vydání: 2022
Předmět:
Zdroj: Repositório Institucional da USP (Biblioteca Digital da Produção Intelectual)
Universidade de São Paulo (USP)
instacron:USP
ISSN: 0272-8842
DOI: 10.1016/j.ceramint.2021.11.211
Popis: AlN compacts with different CaO–Y2O3–C mixtures were sintered between 1100 and 1850 °C to understand the effects of the in situ formed reducing atmosphere on the densification behavior and evolution of the second-phases. AlN with Y2O3 densified at 1750 °C, but the addition of C changed the second-phases evolution towards Y-rich phases that delayed the densification. For AlN containing CaO, the second-phases were little influenced by the reducing atmosphere, but the addition of C increased the evaporation of the second-phase compounds during sintering, limiting the densification due to the reduction of the liquid-phase fraction and the gas trapping inside the pores. AlN with CaO–Y2O3 mixtures could be completely densified at 1650 °C, but the addition of C inhibited the densification below this sintering temperature because liquid-phase had poor wetting and spreading characteristics and the second-phase a high melting point (>1800 °C).
Databáze: OpenAIRE
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