Pretreatment of zirconium diboride powder to improve densification

• Published in: Journal of alloys and compounds Vol. 548; pp. 173 - 179
• Main Authors: Jung, Se-Hyuk, Oh, Hyeon-Cheol, Kim, Jung-Hun, Choi, Sung-Churl, Lee, Sea-Hoon, Kim, Hai-Doo
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 25.01.2013; Elsevier
• Subjects: Cross-disciplinary physics: materials science; rheology; Densification; Density; Etching; Exact sciences and technology; Impurities; Materials science; Materials synthesis; materials processing; Milling; Oxides; Physics; Pretreatment; Sintering; Sintering (powder metallurgy); Ultra-high temperature ceramics; Zirconium; Zirconium diboride; Zirconium diboride; Etching; Densification; Ultra-high temperature ceramics; Milling; Planetary mill; Impurity density; Chemical method; Chemical pretreatment; High temperature; Impurities; Sintering; Zirconium boride
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2012.09.038

► Pretreatment of ZrB2 powder to improve densification of ZrB2. ► Densification of ZrB2 ceramics without the use of sintering additives via milling and etching process as a pretreatment. ► Effect of oxygen content and particle size on ZrB2 densification. In this study, a two-step pretreatment method was used to improve the sinterability of zirconium diboride (ZrB2). Raw powder was initially crushed using a planetary or SPEX mill to an average size of 0.5–0.6μm. Oxide impurities on the surface of the ZrB2 powder were then removed with a dilute hydrofluoric solution. The relative density of the sintered ZrB2 increased as the concentration of residual oxides was reduced. When the concentration of oxide impurities was less than 0.5wt.%, a significant increase in the relative density was observed. Through the proposed pretreatment process, we produced sintered ZrB2 ceramics with a relative density of 99.5% without the use of sintering additives. The results experimentally demonstrate the fact that oxide impurities on the surface of ZrB2 powder are one of the main reasons for inhibiting densification. The sintering behavior of ZrB2 was improved by using mechanical and chemical pretreatment methods.