In-situ spark plasma sintering behavior of La2O3–Y2O3 co-doped AlON ceramics: An attempt to prevent carbon contamination

Aydoğmuş D., Duygulu O., Şahin F.

Journal of Materials Research and Technology, cilt.27, ss.2323-2335, 2023 (SCI-Expanded) identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 27
  • Basım Tarihi: 2023
  • Doi Numarası: 10.1016/j.jmrt.2023.10.047
  • Dergi Adı: Journal of Materials Research and Technology
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Compendex, INSPEC, Directory of Open Access Journals
  • Sayfa Sayıları: ss.2323-2335
  • Anahtar Kelimeler: Aluminum oxynitride, Carbon contamination, Spark plasma sintering, Transparent ceramics
  • İstanbul Teknik Üniversitesi Adresli: Evet

Özet

Un-doped and La2O3–Y2O3 co-doped Aluminum oxynitride (AlON) ceramics were fabricated by reactive spark plasma sintering method (R–SPS) by using Al2O3 and AlN as starting powders with a composition of 70 mol% and 30 mol%, respectively. The effects of co-doping system on densification, microstructure, mechanical properties and optical transmittance of AlON ceramics were investigated. X-ray analysis confirmed the fully transformation of γ-AlON phase for all compositions prepared at 1650 °C in 30 min under 40 MPa under nitrogen. The results indicated that 0.02 wt% La2O3+0.08 wt% Y2O3 added composition had the optimal combination of sintering additives. In an attempt to reduce the graphite contamination, the powder mixture was encapsulated in a Nb-coated graphite foil before subjecting to SPS. Nb-coated graphite foil encapsulated sample was found to reduce carbon contamination leading to high densification (99.6 %) and high transmission (∼81 % at 2500 nm). This study demonstrated that optical transmittance of R-SPSed AlON ceramics is significantly improved without any post-heat treatment by using Nb-coated graphite foil during SPS processing.