The microhardness and microstructural characteristics of bulk molybdenum samples obtained by consolidating nanopowders by plasma pressure compaction

Srivatsan, T. S.; Ravi, B. G.; Petraroli, M.; Sudarshan, T. S.

doi:10.1016/s0263-4368(01)00076-2

Cited by 39 publications

(29 citation statements)

References 15 publications

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“…It has been suggested that the oxide layers cause a charge buildup at the interparticle gaps between the powder particles, which results in some particles being charged negatively with respect to the other particles that are in contact with them. [18] As the charge builds up, the voltage difference is thought to be sufficiently large to generate sparks that trigger an ionization process. The resultant interparticle plasma has been hypothesized to activate the surface of the powder particles by removing the oxide and other contaminants.…”

Section: Plasma Pressure Compactionmentioning

confidence: 99%

“…The resultant interparticle plasma has been hypothesized to activate the surface of the powder particles by removing the oxide and other contaminants. [18] At this stage, the powder compact is heated to higher temperatures so that any adsorbed gas or moisture is released. This is usually indicated by a drop in the initial vacuum level (~0.1 Pa).…”

Section: Plasma Pressure Compactionmentioning

confidence: 99%

“…Fig. 4-Generation of the MSC from the dilatometry data using the method described by Johnson et al [18] Fig. 5-MSR calculated for various values of Q for the MSC generation at three different pressures, 10, 30, and 50 MPa.…”

Section: B Master Sintering Curvementioning

confidence: 99%

“…Conventionally, SiC is densified by hot pressing (HP) or pressureless sintering. [14,15] Recently, new methods, such as plasma pressure compaction (P 2 C), [18] have been developed that generate significantly higher densification rates, thereby decreasing hold times while preventing excessive grain growth.…”

Section: Introductionmentioning

confidence: 99%

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Sintering Behavior of Nanocrystalline Silicon Carbide Using a Plasma Pressure Compaction System: Master Sintering Curve Analysis

Bothara

Atre

Park

et al. 2010

Metall Mater Trans A

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Nanostructured ceramics offer significant improvements in properties over corresponding materials with larger grain sizes on the order of tens to hundreds of micrometers. Silicon carbide (SiC) samples with grain sizes on the order of 100 nm can result in improved strength, chemical resistance, thermal stability, and tailored electrical resistivity. In this study, nanocrystalline SiC was processed in a plasma pressure compaction (P 2 C) system at a temperature of 1973 K (1700°C) that was much lower than the temperatures reported for other sintering techniques. Microstructure of the resulting samples was studied and the hardness and the fracture toughness were measured. The grain sizes were on the order of 700 nm, the hardness between 22 and 24 GPa, and the toughness between 5 and 6.5 MPaAEm 1/2 . The master sintering curve (MSC) analysis was used to model the densification behavior of SiC powder sintered by the P 2 C method. The apparent activation energies for three different pressures of 10, 30, and 50 MPa were obtained to be 1666, 1034, and 1162 kJ/mol, respectively. Although densification occurs via diffusion, the activation energies were higher than those associated with self-diffusion in SiC (between 570 and 920 kJ/mol). A validation study of the MSC was also conducted and the variation in observed density from the density predicted by the MSC was found to range from 1 to 10 pct.

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Section: Plasma Pressure Compactionmentioning

confidence: 99%

Section: Plasma Pressure Compactionmentioning

confidence: 99%

Section: B Master Sintering Curvementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Sintering Behavior of Nanocrystalline Silicon Carbide Using a Plasma Pressure Compaction System: Master Sintering Curve Analysis

Bothara

Atre

Park

et al. 2010

Metall Mater Trans A

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“…As a filter material, porous metals are known to further improve the part's filtering ability if the size of the pores is smaller, since finer pores increase the area that absorbs pollutants. To date, porous metals have largely been fabricated from various elemental and intermetallic systems using a variety of processing routes [19][20][21][22][23][24][25][26]. In this study, metallic glass foams were fabricated by ball milling powder mixtures comprised of metallic glasses and fugitive phases followed by dissolution of the fugitive phases in chemical solution to yield the final porous structure.…”

Section: Introductionmentioning

confidence: 99%

Co Oxidation Properties Of Selective Dissoluted Metallic Glass Composites

Kim¹,

Lee²,

Kim³

et al. 2015

Archives of Metallurgy and Materials

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UTLENIANIE WYBRANYCH ROZCIEŃCZONYCH KOMPOZYTÓW SZKIEŁ METALICZNYCHPorous metallic materials have been widely used in many fields including aerospace, atomic energy, electro chemistry and environmental protection. Their unique structures make them very useful as lightweight structural materials, fluid filters, porous electrodes and catalyst supports. In this study, we fabricated Ni-based porous metallic glasses having uniformly dispersed micro meter pores by the sequential processes of ball-milling and chemical dissolution method. We investigated the application of our porous metal supported for Pt catalyst. The oxidation test was performed in an atmosphere of 1% CO and 3% O 2 . Microstructure observation was performed by using a scanning electron microscope. Oxidation properties and BET (Brunauer, Emmett, and Teller) were analyzed to understand porous structure developments. The results indicated that CO Oxidation reaction was dependent on the specific surface area.

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Powder Metallurgy Route to Ultrafine‐Grained Refractory Metals

Zhang

et al. 2023

Advanced Materials

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Ultrafine‐grained (UFG) refractory metals are promising materials for applications in aerospace, microelectronics, nuclear energy, and many others under extreme environments. Powder metallurgy (PM) allows to produce such materials with well‐controlled chemistry and microstructure at multiple length scales and near‐net shape manufacturing. However, sintering refractory metals to full density while maintaining a fine microstructure is still challenging due to the high sintering temperature and the difficulty to separate the kinetics of densification versus grain growth. Here an overview of the sintering issues, microstructural design rules, and PM practices towards UFG and nanocrystalline refractory metals are sought to be provided. The previous efforts shall be reviewed to address the processing challenges, including the use of fine/nanopowders, second‐phase grain growth inhibitors, and field‐assisted sintering techniques. Recently, pressureless two‐step sintering has been successfully demonstrated in producing dense UFG refractory metals down to ≈300 nm average grain size with a uniform microstructure and this technological breakthrough shall be reviewed. PM progresses in specific materials systems shall be next reviewed, including elementary metals (W and Mo), refractory alloys (W‐Re), refractory high‐entropy alloys, and their composites. Last, future developments and the endeavor towards UFG and nanocrystalline refractory metals with exceptionally uniform microstructure and improved properties are outlined.

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The microhardness and microstructural characteristics of bulk molybdenum samples obtained by consolidating nanopowders by plasma pressure compaction

Cited by 39 publications

References 15 publications

Sintering Behavior of Nanocrystalline Silicon Carbide Using a Plasma Pressure Compaction System: Master Sintering Curve Analysis

Sintering Behavior of Nanocrystalline Silicon Carbide Using a Plasma Pressure Compaction System: Master Sintering Curve Analysis

Co Oxidation Properties Of Selective Dissoluted Metallic Glass Composites

Powder Metallurgy Route to Ultrafine‐Grained Refractory Metals

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