scholarly journals Oxidation behavior of non-stoichiometric (Zr,Hf,Ti)Cx carbide solid solution powders in air

2021 ◽  
Author(s):  
Huilin Lun ◽  
Yi Zeng ◽  
Xiang Xiong ◽  
Ziming Ye ◽  
Zhongwei Zhang ◽  
...  
Keyword(s):  
Solid Solution ◽  
Oxidation Resistance ◽  
Oxidation Behavior ◽  
Group Iv ◽  
Hypersonic Vehicles ◽  
Metal Carbides ◽  
Initial Oxidation ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Kinetics Of

AbstractMulti-component solid solutions with non-stoichiometric compositions are characteristics of ultra-high temperature carbides as promising materials for hypersonic vehicles. However, for group IV transition-metal carbides, the oxidation behavior of multi-component non-stoichiometric (Zr,Hf,Ti)Cx carbide solid solution has not been clarified yet. The present work fabricated four kinds of (Zr,Hf,Ti)Cx carbide solid solution powders by free-pressureless spark plasma sintering to investigate the oxidation behavior of (Zr,Hf,Ti)Cx in air. The effects of metallic atom composition on oxidation resistance were examined. The results indicate that the oxidation kinetics of (Zr,Hf,Ti)Cx are composition dependent. A high Hf content in (Zr,Hf,Ti)Cx was beneficial to form an amorphous Zr-Hf-Ti-C-O oxycarbide layer as an oxygen barrier to enhance the initial oxidation resistance. Meanwhile, an equiatomic ratio of metallic atoms reduced the growth rate of (Zr,Hf,Ti)O2 oxide, increasing its phase stability at high temperatures, which improved the oxidation activation energy of (Zr, Hf, Ti)Cx.

High Temperature Oxidation Behavior of MoSi2 under Low Pressure Atmosphere

2007 ◽  
Vol 561-565 ◽  
pp. 427-430 ◽  
Author(s):  
Akira Ibano ◽  
Kyosuke Yoshimi ◽  
Akira Yamauchi ◽  
Rong Tu ◽  
Kouichi Maruyama ◽  
...  
Keyword(s):  
High Temperature ◽  
High Temperature Oxidation ◽  
Oxidation Behavior ◽  
Ambient Pressure ◽  
Low Pressure ◽  
Initial Oxidation ◽  
Temperature Oxidation ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
High Temperature Oxidation Behavior

In this study, the high temperature oxidation behavior of polycrystalline MoSi2 in a low-pressure atmosphere was investigated. Polycrystalline MoSi2 was produced by the spark plasma sintering process. Oxidation tests were carried out at 1500°C at either 10Torr or 760Torr in an Ar-20%O2 atmosphere. For both conditions, the weight change peaked at the initial oxidation stage, and then their weights gradually increased with increasing oxidation time. The sample weight became heavier in the ambient pressure than in the low-pressure, but the evaporation oxidation was not significant in the low-pressure condition. After the low-pressure oxidation tests, the formation of Mo5Si3 in the MoSi2 substrate was identified. The oxidation resistance of MoSi2 at 1500°C is discussed based on the obtained results.

scholarly journals Comparison of Conventional and Flash Spark Plasma Sintering of Cu–Cr Pseudo-Alloys: Kinetics, Structure, Properties

Metals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 141
Author(s):  
Kirill V. Kuskov ◽  
Mohammad Abedi ◽  
Dmitry O. Moskovskikh ◽  
Illia Serhiienko ◽  
Alexander S. Mukasyan
Keyword(s):  
Heating Rate ◽  
Spark Plasma Sintering ◽  
Electric Circuits ◽  
Nanostructured Particles ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
The Media ◽  
Copper Chromium ◽  
Kinetics Of ◽  
Structure Properties

Spark plasma sintering (SPS) is widely used for the consolidation of different materials. Copper-based pseudo alloys have found a variety of applications including as electrodes in vacuum interrupters of high-voltage electric circuits. How does the kinetics of SPS consolidation for such alloys depend on the heating rate? Do SPS kinetics depend on the microstructure of the media to be sintered? These questions were addressed by the investigation of SPS kinetics in the heating rate range of 0.1 to 50 K/s. The latter conditions were achieved through flash spark plasma sintering (FSPS). We also compared the sintering kinetics for the conventional copper–chromium mixture and for the mechanically induced copper/chromium nanostructured particles. It was shown that, under FSPS conditions, the observed maximum consolidation rates were 20–30 times higher than that for conventional SPS with a heating rate of 100 K/min. Under the investigated conditions, the sintering rate for mechanically induced composite Cu/Cr particles was 2–4 times higher compared to the conventional Cu + Cr mixtures. The apparent sintering activation energy for the Cu/Cr powder was twice less than that for Cu–Cr mixture. It was concluded that the FSPS of nanostructured powders is an efficient approach for the fabrication of pseudo-alloys.

scholarly journals A Study of the Impact of Graphite on the Kinetics of SPS in Nano- and Submicron WC-10%Co Powder Compositions

Ceramics ◽  
2021 ◽  
Vol 4 (2) ◽  
pp. 331-363
Author(s):  
Eugeniy Lantcev ◽  
Aleksey Nokhrin ◽  
Nataliya Malekhonova ◽  
Maksim Boldin ◽  
Vladimir Chuvil'deev ◽  
...  
Keyword(s):  
Activation Energy ◽  
Solid Phase ◽  
Continuous Heating ◽  
Diffusion Creep ◽  
Hard Alloys ◽  
Fine Grained ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
The Impact ◽  
Kinetics Of

This study investigates the impact of carbon on the kinetics of the spark plasma sintering (SPS) of nano- and submicron powders WC-10wt.%Co. Carbon, in the form of graphite, was introduced into powders by mixing. The activation energy of solid-phase sintering was determined for the conditions of isothermal and continuous heating. It has been demonstrated that increasing the carbon content leads to a decrease in the fraction of η-phase particles and a shift of the shrinkage curve towards lower heating temperatures. It has been established that increasing the graphite content in nano- and submicron powders has no significant effect on the SPS activation energy for “mid-range” heating temperatures, QS(I). The value of QS(I) is close to the activation energy of grain-boundary diffusion in cobalt. It has been demonstrated that increasing the content of graphite leads to a significant decrease in the SPS activation energy, QS(II), for “higher-range” heating temperatures due to lower concentration of tungsten atoms in cobalt-based γ-phase. It has been established that the sintering kinetics of fine-grained WC-Co hard alloys is limited by the intensity of diffusion creep of cobalt (Coble creep).

Oxidation Behavior of TiAl Based Alloys Prepared by Spark Plasma Sintering

2010 ◽  
Vol 152-153 ◽  
pp. 940-944
Author(s):  
Hua Chen ◽  
Jing Chao Zhang ◽  
X.Y Lu
Keyword(s):  
Mechanical Alloying ◽  
Spark Plasma Sintering ◽  
Oxidation Behavior ◽  
Mass Gain ◽  
Vacuum Sintering ◽  
Temperature Oxidation ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
High Temperature Oxidation Behavior ◽  
Fully Lamellar

The spark plasma sintering (SPS) microstructure and high temperature oxidation behavior of TiH2-45Al-0.2Si-5Nb(at.%) alloy were investigated.Emphasis was placed on the effect of SPS microstructures, obtained by blend powder and mechanical alloying powder. The mass gain due to oxidation was measured using an electro balance. The oxide layers as well as its micro-structure were examined by SEM and EDS, and XRD. The results show that sintered microstructure of blend powder is composed of fully lamellar TiAl/ Ti3Al phase, and that of the mechanical alloying powder is composed of finer granular TiAl/Ti3Al phase. The latter oxidation rate is lower, and forms continuous mixed oxide layer of Al2O3 and TiO2. Both SPS microstructure of blend powder and mechanical alloying powder are superior in oxidation behavior to ordinary vacuum sintering.

Oxidation behavior of Si- rich Mo-Si-B coating doped with La by spark plasma sintering

2021 ◽  
Vol 192 ◽  
pp. 109762
Author(s):  
Zilong Wu ◽  
Kanglu Feng ◽  
Jiangbo Sha ◽  
Chungen Zhou
Keyword(s):  
Spark Plasma Sintering ◽  
Oxidation Behavior ◽  
Plasma Sintering ◽  
Spark Plasma

scholarly journals Refractory High-Entropy HfTaTiNbZr-Based Alloys by Combined Use of Ball Milling and Spark Plasma Sintering: Effect of Milling Intensity

Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1268 ◽  
Author(s):  
Natalia Shkodich ◽  
Alexey Sedegov ◽  
Kirill Kuskov ◽  
Sergey Busurin ◽  
Yury Scheck ◽  
...  
Keyword(s):  
Solid Solution ◽  
Ball Milling ◽  
Spark Plasma Sintering ◽  
Vickers Hardness ◽  
High Energy ◽  
High Entropy Alloy ◽  
High Entropy ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Energy Ball

For the first time, a powder of refractory body-centered cubic (bcc) HfTaTiNbZr-based high-entropy alloy (RHEA) was prepared by short-term (90 min) high-energy ball milling (HEBM) followed by spark plasma sintering (SPS) at 1300 °C for 10 min and the resultant bulk material was characterized by XRD and SEM/EDX. The material showed ultra-high Vickers hardness (10.7 GPa) and a density of 9.87 ± 0.18 g/cm³ (98.7%). Our alloy was found to consist of HfZrTiTaNb-based solid solution with bcc structure as a main phase, a hexagonal closest packed (hcp) Hf/Zr-based solid solution, and Me2Fe phases (Me = Hf, Zr) as minor admixtures. Principal elements of the HEA phase were uniformly distributed over the bulk of HfTaTiNbZr-based alloy. Similar alloys synthesized without milling or in the case of low-energy ball milling (LEBM, 10 h) consisted of a bcc HEA and a Hf/Zr-rich hcp solid solution; in this case, the Vickers hardness of such alloys was found to have a value of 6.4 GPa and 5.8 GPa, respectively.

Oxidation Behavior of Ta-W Alloy

2020 ◽  
Vol 993 ◽  
pp. 299-306
Author(s):  
Jia Xin Li ◽  
Yu Hong Chen ◽  
Zhang Jun Bai ◽  
Shuai Du ◽  
Lan Er Wu
Keyword(s):  
Solid Solution ◽  
Coefficient Of Thermal Expansion ◽  
Complex Oxide ◽  
Tungsten Alloy ◽  
Good Effect ◽  
Initial Oxidation ◽  
Compressive Stresses ◽  
Initial Stage ◽  
Kinetics Of ◽  
Oxidation Behaviors

The oxidation behaviors of tantalum-tungsten alloy with 10-20% W was investigated between temperature range of 700 to 900 °C exposed in air. The kinetics of Ta-W alloy was determined by TG-DTA, the characteristics of oxides were analyzed by SEM, EDS and XRD. The oxidation tests revealed that the alloys obeyed parabolic kinetic in the initial stage, then translated in linear law. The addition of W has a good effect on the oxidation resistance of Ta-W alloys at experimental temperature. Solid solution of Ta2O5 form in case of oxidation product of Ta-10W, Ta-15W alloys, while the complex oxide Ta22W4O67 form after Ta-20W alloy oxidized. The formation of solid solution and complex oxide impeded the volatilization. The compact oxide film protects the penetration of oxygen in the initial oxidation stage. The large compressive stresses and mismatch of the coefficient of thermal expansion between oxide scale and matrix alloys make the oxides layer be broken, which cause kinetic of oxidization obeying linear law.

The Influence of Porous Structure on the Interdiffusion Kinetics of Cu-Ni System During Spark Plasma Sintering

2020 ◽  
Vol 51 (4) ◽  
pp. 1799-1807
Author(s):  
Ruidi Li ◽  
Pengda Niu ◽  
Shenghua Deng ◽  
Linjun Tang ◽  
Siyao Xie ◽  
...  
Keyword(s):  
Porous Structure ◽  
Spark Plasma Sintering ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Interdiffusion Kinetics ◽  
Kinetics Of
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