Synthesis of HfB2 Powders by Carbothermal Reduction

Authors

  • Mashhadi, M. 2. Department of Composite Materials Engineering, Malek Ashtar University of Technology, Tehran, Iran.
  • Shirvani, M. 1. Department of Nano Materials Engineering, Malek Ashtar University of Technology, Tehran, Iran.
  • Yosofi, M. 3. Department of Chemistry, Payamenoor University, Isfahan, Iran.
Abstract:

In this research, solid state carbothermal synthesis of HfB2 Nano powders was investigated. For this purpose, HfO2,H3BO3, carbon active or phenolic resin were used as raw materials for carbothermal reaction. After 2-4 hours of milling the raw materials by a planetary ball in an ethanol media, the mixture was heat dried and pressed in to disks under pressure of 20-30 bar. The disks were then placed in a graphite crucible and heat-treated at 1500–1600 °C for 1 hour under flowing Ar atmosphere. The powder product was analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and backscattered electron (BSE) imaging. The heat treatment temperature, amount of boric acid, milling and heat treatment time were recognized as four factors influencing synthesis and size of HfB2 powder particles. SEM images reported irregular morphologies with a particle size of about 2-4 µm for HfB2 powder. The best sample was obtained at a molar ratio of HfO2 : phenolic resin carbon: boric acid = 1:5:5 at 1600 °C after 1 hour of heat treatment. XRD results confirmed synthesis of pure HfB2 with a crystallite size of about 60 nm.

Upgrade to premium to download articles

Sign up to access the full text

Already have an account?login

similar resources

Synthesis of Ti4O7 Nanoparticles by Carbothermal Reduction Using Microwave Rapid Heating

The polymer electrolyte fuel cell (PEFC) is an attractive power generation method from the perspective of environmental protection. Carbon is usually used as a catalyst support in PEFC, but it is oxidized under high electrical potential conditions. Ti4O7 is expected as a new catalyst support because of its high electrical conductivity and chemical resistivity. Though Ti4O7 as a catalyst support...

full text

Route to GaN and VN assisted by carbothermal reduction process.

A route to prepare nitrides, such as GaN, VN, and other nitrides, is reported. The reaction pathway involves a two-step process by using the as-synthesized a-C3N3.69 as precursor. The route is so potent that a series of nitrides can be directly synthesized from their oxides at moderate temperatures. A striking feature of this method lies in that a-C3N3.69 is found to play double roles as both c...

full text

ALUMINOTHERMIC-CARBOTHERMAL REDUCTION SYNTHESIS OF NANO CRYSTALLINE Al2O3-Ti(C,N) COMPOSITE WITH DIFFERENT BED TYPES

Ceramic-matrix composites containing TiC-TiN have been used in a variety of application because of their superior properties such as high hardness, good wear resistance and high chemical stability. In this research, effect of coke and coke/calcium beds in synthesis of Al 2O3-Ti(C, N) composites using alumino-carbothermic reduction of TiO 2 has been investigated. Al, TiO 2 and active ca...

full text

SYNTHESIS OF AL2O3-NI COMPOSITE POWDERS BY CO-PRECIPITATION METHOD

The synthesis of micro-sized, uniformly distributed Al2O3-15Vol% Ni powders were studied through three step co-precipitation of hydroxides mixtures from proper solution, calcination at air atmosphere and final step of calcined powders in a carbon bed. Al and Ni hydroxide and amorphous phase were first obtained from their salt’s solutions through chemical co-precipitation method by adjusti...

full text

In Situ Investigation of the Carbothermal Reduction of ZnO Nanowires

Carbothermal reduction is among the oldest chemical processes, commonly used in the production of metals from the corresponding metal oxides or ores (e.g., iron from iron oxides). By using carbon as a reducing agent, decomposition of metal oxides at temperatures much lower than their typical decomposition temperatures can occur. However, a detailed fundamental understanding of such a reaction p...

full text

My Resources

Save resource for easier access later

Save to my library Already added to my library

{@ msg_add @}


Journal title

volume 38  issue 4

pages  75- 85

publication date 2020-01

By following a journal you will be notified via email when a new issue of this journal is published.

Keywords

No Keywords

Hosted on Doprax cloud platform doprax.com

copyright © 2015-2023