Application of Mechanical Activation for Production of Zirconate Pyrochlore Ceramic Containing Simulated Rare-Earth: Actinide Fraction of HLW

2003 ◽  
Author(s):  
S. V. Stefanovsky ◽  
S. V. Chizhevskaya ◽  
O. I. Kirjanova ◽  
N. S. Mikhailenko ◽  
B. S. Nikonov
Keyword(s):  
Mechanical Properties ◽  
Rare Earth ◽  
Mechanical Activation ◽  
Chemical Durability ◽  
Cold Pressing ◽  
Oxide Powders ◽  
Sintering Time ◽  
Ceramic Samples ◽  
Plasma Melting ◽  
Preliminary Mechanical Activation

Samples of zirconate pyrochlore ceramic (Ln)2(Zr,U)2O7 (Ln - lanthanides) containing simulated REE-An fraction of HLW were synthesized by conventional cold pressing of oxide mixtures in pellets under pressure of 200 MPa and sintering of pellets at 1550 °C for 24 hours and using preliminary mechanical activation of oxide powders for 5 or 10 min with a reduced sintering time for 6 hours. One more sample was produced by plasma melting. All the ceramic samples sintered at 1550 °C were monolithic and dense with high mechanically activated powders had higher chemical durability and mechanical properties.

scholarly journals Effect of Graphene Nanosheets Content on Microstructure and Mechanical Properties of Titanium Matrix Composite Produced by Cold Pressing and Sintering

Nanomaterials ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 1024 ◽  
Author(s):  
Milad Haghighi ◽  
Mohammad Shaeri ◽  
Arman Sedghi ◽  
Faramarz Djavanroodi
Keyword(s):  
Mechanical Properties ◽  
Matrix Composite ◽  
Volume Fraction ◽  
Graphene Nanosheets ◽  
Microstructural Analysis ◽  
Titanium Matrix ◽  
Titanium Matrix Composite ◽  
Cold Pressing ◽  
Sintering Time ◽  
Microstructure And Mechanical Properties

The effect of graphene nanosheet (GNS) reinforcement on the microstructure and mechanical properties of the titanium matrix composite has been discussed. For this purpose, composites with various GNS contents were prepared by cold pressing and sintering at various time periods. Density calculation by Archimedes’ principle revealed that Ti/GNSs composites with reasonable high density (more than 99.5% of theoretical density) were produced after sintering for 5 h. Microstructural analysis by X-ray diffraction (XRD) and a field emission scanning electron microscope (FESEM) showed that TiC particles were formed in the matrix during the sintering process as a result of a titanium reaction with carbon. Higher GNS content as well as sintering time resulted in an increase in TiC particle size and volume fraction. Microhardness and shear punch tests demonstrated considerable improvement of the specimens’ mechanical properties with the increment of sintering time and GNS content up to 1 wt. %. The microhardness and shear strength of 1 wt. % GNS composites were enhanced from 316 HV and 610 MPa to 613 HV and 754 MPa, respectively, when composites sintered for 5 h. It is worth mentioning that the formation of the agglomerates of unreacted GNSs in 1.5 wt. % GNS composites resulted in a dramatic decrease in mechanical properties.

scholarly journals Investigation of Structure and Physico-Mechanical Properties of Composite Materials Based on Copper - Carbon Nanoparticles Powder Systems

2015 ◽  
Vol 60 (1) ◽  
pp. 51-55
Author(s):  
V. Kovtun ◽  
V. Pasovets ◽  
T. Pieczonka
Keyword(s):  
Mechanical Properties ◽  
Mechanical Activation ◽  
Metal Matrix ◽  
Carbon Nanoparticles ◽  
Copper Matrix ◽  
Metal Particles ◽  
Powder Materials ◽  
Sintered Copper ◽  
Mechanical Bonding ◽  
Preliminary Mechanical Activation

Abstract Physico-mechanical and structural properties of electrocontact sintered copper matrix- carbon nanoparticles composite powder materials are presented. Scanning electron microscopy revealed the influence of preliminary mechanical activation of the powder system on distribution of carbon nanoparticles in the metal matrix. Mechanical activation ensures mechanical bonding of nanoparticles to the surface of metal particles, thus giving a possibility for manufacture of a composite with high physico-mechanical properties.

Mechanical Properties of α- and β-SiAlON Composite Ceramics Using β-SiAlON Powder

2008 ◽  
Vol 403 ◽  
pp. 111-114 ◽  
Author(s):  
Kei Asakoshi ◽  
Junichi Tatami ◽  
Katsutoshi Komeya ◽  
Takeshi Meguro ◽  
Masahiro Yokouchi
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Rare Earth ◽  
Chemical Composition ◽  
Metal Oxides ◽  
Bending Strength ◽  
Rare Earth Oxide ◽  
Composite Ceramics ◽  
Oxide Powders ◽  
Sialon Powder

β-SiAlON powder was used as a raw powder to fabricate α/β-SiAlON composite ceramics with different rare earth elements. The phases present in the sample fabricated from -SiAlON, α-Si3N4, AlN, and rare earth oxide powders were - and -SiAlONs. The composition was dependent on the chemical composition and firing profile. The sample obtained by adding Yb2O3 had a high -SiAlON content. The /-SiAlON composite ceramics had high densit. Their microstructures depended on the used metal oxides, namely, the addition of Nd2O3 and CaCO3 resulted in the elongation of the -SiAlON grains. The bending strength, fracture toughness, and hardness were influenced by the -SiAlON content, amount of elongated grains, and density of the sample.

Murataite-based ceramics for actinide waste immobilization

1999 ◽  
Vol 556 ◽  
Author(s):  
S. V. Stefanovsky ◽  
S. V. Yudintse ◽  
B. S. Nikonov ◽  
B. I. Omelianenko ◽  
A. G. Ptashkin
Keyword(s):  
Rare Earth ◽  
Chemical Durability ◽  
Isomorphic Substitution ◽  
Cold Crucible ◽  
Hydrothermal Conditions ◽  
High Chemical ◽  
Ceramic Samples ◽  
Waste Immobilization ◽  
Very High ◽  
Xrd And Tem

AbstractStudying the Synroc, doped with a simulated HLW, we have found, along with conventional Synroc phases (zirconolite, perovskite, hollandite), an extra phase with a stoichiornetry (Ca, Mn, U, TR)4(U, TR, Zr, Ti) 2(AI, Ti)7O22. XRD and TEM study has shown this phase is related to a very rare mineral murataite. In the present work a ceramic based on murataite is studied. The ceramic samples in the system: Ca-Mn-Ti-Zr-U-Ce-AI-Fe-O were produced and examined in details using XRD, SEM/EDS, TEM, and optical microscopy. Total amount of actinide (U) and rare earth (Ce, Gd) elements in the murataite exceeds 20 wt%. Isomorphic substitution schemes in the structures of synthetic and natural murataites are discussed. High isomorphic capacity of the murataite structure towards actinides and REEs, flexibility of its composition, feasibility of synthesis by melting, including a cold crucible melting, and very high chemical durability under hydrothermal conditions make the murataite-based ceramics very promising for actinides and excess weapon Pu fixation.

scholarly journals Improving the microstructure and mechanical properties of laser cladded Ni-based alloy coatings by changing their composition: A review

2020 ◽  
Vol 59 (1) ◽  
pp. 340-351
Author(s):  
Lin Yinghua ◽  
Ping Xuelong ◽  
Kuang Jiacai ◽  
Deng Yingjun
Keyword(s):  
Mechanical Properties ◽  
Wear Resistance ◽  
Corrosion Resistance ◽  
Rare Earth ◽  
Composite Coatings ◽  
Single Element ◽  
Properties Of Coatings ◽  
Hard Particles ◽  
Microstructure And Mechanical Properties ◽  
Nickel Based Alloy

AbstractNi-based alloy coatings prepared by laser cladding has high bonding strength, excellent wear resistance and corrosion resistance. The mechanical properties of coatings can be further improved by changing the composition of alloy powders. This paper reviewed the improved microstructure and mechanical properties of Ni-based composite coatings by hard particles, single element and rare earth elements. The problems that need to be solved for the particle-reinforced nickel-based alloy coatings are pointed out. The prospects of the research are also discussed.

The correlation between the coercivity and the mechanical properties of sintered rare-earth-iron-boron magnets

1994 ◽  
Vol 6 (19) ◽  
pp. 3573-3582 ◽  
Author(s):  
S Szymura ◽  
Y M Rabinovich ◽  
H Bala ◽  
A D Maysterenko
Keyword(s):  
Mechanical Properties ◽  
Rare Earth

Effect of the Neodymium Content on Mechanical Properties of the Electro-Brush Plated Nano-Al2O3/Ni Composite Coating

2012 ◽  
Vol 525-526 ◽  
pp. 277-280
Author(s):  
Guo Jin ◽  
Xiu Fang Cui ◽  
Er Bao Liu ◽  
Qing Fen Li
Keyword(s):  
Mechanical Properties ◽  
Rare Earth ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Composite Coating ◽  
Nanoindentation Test ◽  
X Ray Diffraction ◽  
X Ray ◽  
Small Cracks ◽  
Scanning Electron

The effect of the neodymium content on mechanical properties of the electro-brush plated nanoAl2O3/Ni composite coating was investigated in this paper. The microstructure and phase structure were studied with scanning electron microscope (SEM) and X-ray diffraction (XRD). The hardness and abrasion properties of several coatings with different neodymium content were studied by nanoindentation test and friction / wear experiment. Results show that the coatings are much finer and more compact when the neodymium was added, and the hardness and abrasion property of the coatings with neodymium were improved obviously. Besides, the small cracks conduced by the upgrowth stress in the coatings were ameliorated when the rare earth neodymium was added. The improvement mechanism was further discussed.

Structure and mechanical properties of rare-earth complex La-GDTC modified silica/SBR composites

Polymer ◽  
2011 ◽  
Vol 52 (12) ◽  
pp. 2701-2710 ◽  
Author(s):  
Shuyan Yang ◽  
Lan Liu ◽  
Zhixin Jia ◽  
Demin Jia ◽  
Yuanfang Luo
Keyword(s):  
Mechanical Properties ◽  
Rare Earth ◽  
Rare Earth Complex ◽  
Modified Silica
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