Effect of Na2CO3 on hexagonal boron nitride prepared from urea and boric acid

ÇAMURLU H. E.

CERAMICS INTERNATIONAL, cilt.37, sa.6, ss.1993-1999, 2011 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 37 Sayı: 6
  • Basım Tarihi: 2011
  • Doi Numarası: 10.1016/j.ceramint.2011.02.011
  • Dergi Adı: CERAMICS INTERNATIONAL
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Sayfa Sayıları: ss.1993-1999
  • Anahtar Kelimeler: Grain growth, Powders: chemical preparation, Nitrides, Hexagonal boron nitride, CARBOTHERMIC FORMATION
  • Akdeniz Üniversitesi Adresli: Evet

Özet

Formation of hexagonal boron nitride (hBN) from a precursor obtained by the reaction of urea and boric acid was studied in nitrogen, ammonia and argon atmospheres in 700-1200 degrees C temperature range. Effect of sodium carbonate (Na2CO3) addition on this process was investigated. Reaction products were subjected to X-ray diffraction, particle size distribution, gravimetric and Fourier transformed infrared spectroscopy analyses. Particle size and crystallite thickness of the formed hBN were seen to increase from about 60 nm and 5 nm at 700 degrees C to 230 nm and 19 rim at 1200 degrees C, respectively in NH3 atmosphere with Na2CO3 addition. Highest conversion of boron in the precursor into ON was achieved as 73.6% when Na2CO3 added precursor was reacted at 1200 degrees C in NH3. hBN powder with high yield and relatively large particle size was obtained at low temperature such as 1200 degrees C with Na2CO3 addition. Role of Na2CO3 addition was suggested to be formation of a sodium borate melt from which hBN crystallized via the reaction of borate and nitrogen ions in the melt. Obtained hBN has the potential for utilization as a clean starting material for synthesis of B or N containing compounds. (C) 2011 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

Formation of hexagonal boron nitride (hBN) from a precursor obtained by the reaction of urea and boric acid was studied in nitrogen, ammonia and argon atmospheres in 700-1200 degrees C temperature range. Effect of sodium carbonate (Na2CO3) addition on this process was investigated. Reaction products were subjected to X-ray diffraction, particle size distribution, gravimetric and Fourier transformed infrared spectroscopy analyses. Particle size and crystallite thickness of the formed hBN were seen to increase from about 60 nm and 5 nm at 700 degrees C to 230 nm and 19 rim at 1200 degrees C, respectively in NH3 atmosphere with Na2CO3 addition. Highest conversion of boron in the precursor into ON was achieved as 73.6% when Na2CO3 added precursor was reacted at 1200 degrees C in NH3. hBN powder with high yield and relatively large particle size was obtained at low temperature such as 1200 degrees C with Na2CO3 addition. Role of Na2CO3 addition was suggested to be formation of a sodium borate melt from which hBN crystallized via the reaction of borate and nitrogen ions in the melt. Obtained hBN has the potential for utilization as a clean starting material for synthesis of B or N containing compounds. (C) 2011 Elsevier Ltd and Techna Group S.r.l. All rights reserved