Seda TAŞDEMİR, Betül KAFKASLIOĞLU YILDIZ, Elif IŞIK, Yahya TÜR

Sm2O3 Nadir Toprak Oksit Katkılı Al2O3 Seramiklerinin Mikro Yapısının ve Eğilme Dayanımının İncelenmesi: Hacim Oranlarının ve Sinterleme Sıcaklıklarının Etkisi

Düşük miktarlarda (0, 0,1, 0,3, 0,5, 0,8, 1, 2 hac.%) Sm2O3'ün Al2O3'ün yoğunlaşma, mikroyapı ve eğilme dayanımı üzerindeki etkileri farklı sinterleme sıcaklıkları için incelenmiştir. Sm2O3 ve Al2O3 tozları bilyeli öğütme ile karıştırılmış ve Al2O3-Sm2O3 seramikleri, ayrı ayrı 1550°C'de ve 1600°C/2 saat havada basınçsız sinterlemeden önce disk formunda kuru ve soğuk izostatik presleme ile hazırlanmıştır. Sm2O3, Al2O3 ile reaksiyona girerek SmAlO3 oluşturmuştur. SmAlO3'ün çubuk benzeri morfolojisi, 1600°C'de sinterleme için genel olarak hacimce %0,8 ve 1 Sm2O3 için elde edilirken, 1550°C'de sinterlenen numunelerde çubuk benzeri form daha belirgin olmuştur. Her iki sinterleme sıcaklığında da tüm Sm2O3 oranları için benzer relatif yoğunluklar elde edilmiştir ancak 1550°C'de sinterlenen Al2O3, 1600°C'de sinterlenen Al2O3’e göre daha yüksek yoğunlaşma sergilemiştir. 1600°C'de sinterlenen hac.%0,5 Sm2O3 içeren seramiklerde, Al2O3'e göre daha yüksek yoğunlaşma sebebiyle yaklaşık %5'lik bir mukavemet artışı elde edilirken, mukavemet değerleri genelde birbirine yakın olmuştur. Mukavemet, 1550°C'de sinterleme için hac.%0,1 Sm2O3 oranının üzerinde belirgin bir düşüş göstermiştir. Mevcut miktarlarda Sm2O3 ilavesinin Al2O3'ün mekanik özellikleri üzerinde önemli bir etkisi olmamıştır, ancak mikroyapıyı değiştirmiştir.

Anahtar Kelimeler:

Al2O3, Sm2O3, mikroyapı, mekanik özellikler

Exploring Microstructure and Bending Strength of Al2O3 Ceramics Doped with Sm2O3 Rare-Earth Oxide: Impact of Volume Ratios and Sintering Temperatures

The effects of low amounts (0, 0.1, 0.3, 0.5, 0.8, 1, 2vol%) of Sm2O3 on the densification, microstructure, and bending strength of Al2O3 were studied for different sintering temperatures. Sm2O3 and Al2O3 powders were mixed by ball milling, and Al2O3-Sm2O3 ceramics were prepared by dry and cold isostatic pressing in disc form before pressureless sintering at 1550°C and 1600°C/2 h in the air, separately. Sm2O3 reacted with Al2O3 by forming SmAlO3. The rod-like morphology of the SmAlO3 was generally achieved for 0.8 and 1vol% Sm2O3 for sintering at 1600°C, whereas the rod-like form was more obvious for the samples sintered at 1550°C. Similar relative densities were attained for all Sm2O3 ratios at both sintering temperatures, but the Al2O3 sintered at 1550°C exhibited higher densification than the Al2O3 sintered at 1600°C. The strength values were close, while a strength increase of about 5% was obtained for 0.5 vol% Sm2O3 containing ceramics sintered at 1600°C caused by the higher densification compared to the Al2O3. The strength showed a prominent drop above the ratio of 0.1 vol% Sm2O3 for sintering at 1550°C. The addition of present amounts of Sm2O3 did not have a significant effect on the mechanical properties of Al2O3 but it changed the microstructure.

Keywords:

Al2O3, Sm2O3, microstructure, mechanical properties,

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