Synthesis of bulk nanocrystalline HfB2 from HfCl4–NaBH4–Mg ternary system

Nazlı Akçamlı*, Duygu Ağaoğulları, Özge Balcı, M. Lütfi Öveçoğlu, İsmail Duman

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)

Abstract

This study reports on the synthesis and consolidation of pure HfB2 powders starting from HfCl4–NaBH4–Mg blends via autoclave processing, annealing and purification followed by pressureless sintering (PS, with 2 wt% Co aid) or spark plasma sintering (SPS). During autoclave reactions conducted at 500 °C for 12 h under autogenic pressure, excess amounts of NaBH4 were utilized to investigate its effects on the reaction products and mechanism. A subsequent washing (with distilled water), annealing (at 750, 1000 and 1700 °C) and acid leaching (HCl) were applied on the as-synthesized products. Pure HfB2 powders with an average particle size of 145 nm were obtained after autoclave synthesis in the presence of 200 wt% excess NaBH4, washing, annealing at 1000 °C for 3 h and 6 M HCl leaching. SPS sample has higher relative density and microhardness values (94.18% and 20.99 GPa, respectively) than those of PS sample (90.14% and 14.85 GPa). Relative wear resistance was improved considerably (8.2 times) by employing SPS technique.

Original languageEnglish
Pages (from-to)12689-12705
Number of pages17
JournalJournal of Materials Science
Volume52
Issue number21
DOIs
Publication statusPublished - 1 Nov 2017

Bibliographical note

Publisher Copyright:
© 2017, Springer Science+Business Media, LLC.

Fingerprint

Dive into the research topics of 'Synthesis of bulk nanocrystalline HfB2 from HfCl4–NaBH4–Mg ternary system'. Together they form a unique fingerprint.

Cite this