USE OF PARTIALLY HYDROLYZED PVA FOR BORON CARBIDE SYNTHESIS FROM POLYMERIC PRECURSOR


Karaahmet O., ÇİÇEK B.

CERAMICS-SILIKATY, cilt.64, sa.4, ss.434-446, 2020 (SCI İndekslerine Giren Dergi) identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 64 Konu: 4
  • Basım Tarihi: 2020
  • Doi Numarası: 10.13168/cs.2020.0031
  • Dergi Adı: CERAMICS-SILIKATY
  • Sayfa Sayıları: ss.434-446

Özet

Boron carbide (B4C) synthesis from a polymeric precursor is an alternative to a traditional carbothermal reduction, promising low energy consumption and production costs, particularly for a polymeric precursor such as polyvinyl borate (PVBO). The sol-gel technique is preferred in the production of polymeric precursors owing to its convenience in producing single-source reactants for synthesizing B4C at low temperatures (< 1800 degrees C). The sol-gel parameters, such as the composition, viscosity, and pH, affect the formation of the polymeric precursor. In this study, industrial-grade partially hydrolyzed PVA and technical-grade boric acid (H3BO3) are used to produce PVBO. We aim to specify the viscosity and pH values for different ratios of PVA:H3BO3. A sample with a weight ratio of PVA:H3BO3 of 1:1 (PHD101) is determined to have the optimum process parameters. Calcination is performed between 500 degrees C and 700 degrees C for 1-3 h to produce a single-source reactant, which consists of boron oxide (B2O3) and carbon. It was observed that B2O3 was distributed on the nano-scale level in the carbon matrix. The reactant is heat-treated at 1400 degrees C for 5 h and crystalline, polyhedral, and irregular B4C particles are synthesized at low temperatures from industrial grade raw materials.