Synthesis of a Fine (Ta_0.8,Hf_0.2)C Powder from Carbide or Oxide Powder Mixtures

Abstract

Tantalum hafnium carbide ((Ta 0.8 ,Hf 0.2 )C) powders were successfully synthesized using a modified spark plasma sintering (SPS) apparatus with TaC/HfC or Ta 2 O 5 /HfO 2 /C starting materials. The (Ta 0.8 ,Hf 0.2 )C obtained from the carbides had a finer particle size of 220 nm, whereas those obtained from the oxides had less contamination during the milling process (0.35 wt%) than the other case. Particle coarsening of the solid-solution phase was effectively suppressed by using a modified SPS apparatus because of the fast heating/cooling rate. High-energy ball milling promoted a solid-solution reaction for the formation of (Ta 0.8 ,Hf 0.2 )C by refining the size and inducing the homogeneous mixing of the starting materials. By the combination of the fast heating and high-energy ball milling, fine tantalum hafnium carbide powders with low contamination were successfully synthesized.W. Fahrenholtz-contributing editor Manuscript No. 37549.

Dense and pure high-entropy metal diboride ceramics sintered from self-synthesized powders via boro/carbothermal reduction approach

“…ground in an agate mortar by pestle and sieved through a 200-mesh screen. Field-assisted synthesis has been proven to be efficient for the fast synthesis of high purity UHTC powders [37,38]. In this work, a quantity of 20 g mixtures for each composition was then placed in a graphite crucible for reduction processing in a SPS system (ED-PAS-111, ELENX, Japan).…”

Synthesis of YB2C2 by high‐energy ball milling and reactive spark plasma sintering

“…Spark plasma sintering (SPS) has been recently used for the densification of refractory ceramics due to the combination of its unique features such as fast heating/cooling rate, low sintering/synthesis temperature, and short sintering time. 11,[14][15][16][17][18][19] The SPS process also has an advantage for powder synthesis because the current which passes through the specimens during SPS was reported to increase the rate of compound formation and decrease the incubation time for the nucleation of the new phases. 20 In addition, the formation of undesirable secondary phases and growth of particles during the heating stage may be minimized due to the fast heating rate of SPS (>100°C/ min), low synthesis temperature, and short holding time.…”

“…As a consequence, modified SPS processes have been used for synthesizing ceramic compound powders. 3,[14][15][16][17][21][22][23][24] The size of the starting powder has a significant effect on the densification behavior. Reducing the particle size to nanoscale has been shown to be an efficient way to enhance densification at lower sintering temperatures.…”

Bond characteristics, mechanical properties, and high‐temperature thermal conductivity of (Hf1−xTax)C composites

“…Producing solid solution composites has employed for improving material properties of cubic transition metal carbides, 7 and various studies of transition metal carbides and nitrides have yielded new solid solution composites with enhanced properties. [8][9][10][11] There have been some theoretical studies of the elastic, mechanical, and electronic | 6299 KIM et al properties of the composites 5,12 ; however, only limited information is available. Besides, although (Hf 1−x Ta x )C solid solution composites have been synthesized, there are few data on their elastic, mechanical, electronic, and melting behaviors due to experimental difficulties arising from the high-temperature stability of the individual carbides, TaC and HfC.…”