Effects of aluminum content and particle size on volume expansion during the sintering of Fe-Al mixed powders

2018 ◽  
Vol 747 ◽  
pp. 211-216 ◽  
Author(s):  
Yong-In Kim ◽  
Wonsik Lee ◽  
Jin Man Jang ◽  
Sang Wook Ui ◽  
Gye Seok An ◽  
...  
Keyword(s):  
Particle Size ◽  
Volume Expansion ◽  
Aluminum Content

Hydration and Expansion Properties of Novel Concrete Expansive Agent

2009 ◽  
Vol 405-406 ◽  
pp. 267-271
Author(s):  
Pei Wei Gao ◽  
Fei Geng ◽  
Xiao Lin Lu
Keyword(s):  
Particle Size ◽  
Volume Expansion ◽  
Curing Temperature ◽  
Expansion Rate ◽  
The Novel ◽  
Expansive Agent ◽  
Novel Agent

The hydration and expansive characterization of a novel concrete expansive agent were investigated in this paper. The results showed that the hydration activities of the novel agent depended on the calcining temperature, particle size and curing temperature. When the expansive agent was mixed in concrete, the early shrinkage of concrete was reduced. If the content and distribution of the expansive agent in concrete is appropriate and uniform, the expansion rate of concrete may be controlled, and the shrinkage of concrete could be compensated effectively by the gentle volume expansion.

Experimental Investigations on Expansion Performance of Alkali-Aggregate Reaction of Mortar

2013 ◽  
Vol 405-408 ◽  
pp. 2719-2723
Author(s):  
Feng Ouyang ◽  
Da Chen ◽  
Ying Di Liao ◽  
Chao Hua Jiang
Keyword(s):  
Particle Size ◽  
Reaction Time ◽  
Volume Expansion ◽  
Size Composition ◽  
Expansion Ratio ◽  
Experimental Investigations ◽  
Distinguishing Characteristic ◽  
Alkali Aggregate Reaction ◽  
Result Show ◽  
Function Relationship

Volume expansion is the distinguishing characteristic of concrete occurring AAR. Expansion performance of mortar with different particle size composition aggregate was tested in this paper. The result show that MR specimens with part alkali active sand and R specimens with total alkali active sand present obvious expansion. But expansion ratio of NR specimen with inactive sand remains generally stable and is only 0.02%. Ultimate expansion ratio of specimen due to AAR is not in proportion to content of alkali active aggregate. There is a possible ratio for alkali active aggregate and inactive aggregate to acquire a larger ultimate expansion account. Furthermore, expansion ratio of specimens due to AAR and reaction time present the exponential function relationship.

Thermodynamic investigations of zeolites NaX and NaY

2006 ◽  
Vol 84 (2) ◽  
pp. 134-139 ◽  
Author(s):  
Liyan Qiu ◽  
Patricia A Laws ◽  
Bi-Zeng Zhan ◽  
Mary Anne White
Keyword(s):  
Particle Size ◽  
Heat Capacity ◽  
Phase Transitions ◽  
Size Effect ◽  
Thermodynamic Stability ◽  
Aluminum Content ◽  
Particle Size Effect ◽  
Al Content ◽  
Heat Capacity Measurements ◽  
Zeolitic Materials

Understanding of the thermodynamic stability of zeolites is important in the prediction of thermodynamic equilibrium. Therefore, we have undertaken an investigation of the thermodynamic stability of the zeolites NaX and NaY through heat capacity measurements from ca. 30 to 300 K. No phase transitions were observed, and zeolite NaX does not show a significant particle size effect when the particle size is reduced to ca. 30 nm. The results show that the specific heat capacity increases with the Al content in the zeolite. Both NaX and NaY are found to be thermodynamically stable with respect to their elements because of enthalpic stabilization and with slight entropic destabilization. These data are used along with literature data for many other zeolitic materials to show that the thermodynamic stability of zeolites is enhanced with increasing aluminum content. Key words: zeolite, heat capacity, thermodynamic stability, nano effects.

scholarly journals Effects of heating rate, quartz particle size, viscosity, and form of glass additives on high‐level waste melter feed volume expansion

2016 ◽  
Vol 100 (2) ◽  
pp. 583-591 ◽  
Author(s):  
SeungMin Lee ◽  
Bradley J. VanderVeer ◽  
Pavel Hrma ◽  
Zachary J. Hilliard ◽  
Jayven S. Heilman‐Moore ◽  
...  
Keyword(s):  
Particle Size ◽  
Heating Rate ◽  
Volume Expansion ◽  
High Level Waste ◽  
Quartz Particle ◽  
High Level ◽  
Feed Volume

Investigating the Effects of Diluting Solutions and Trace Metal Contamination on Aggregation Characteristics of Silica-Based ILD CMP Slurries

2005 ◽  
Vol 867 ◽  
Author(s):  
D. DeNardis ◽  
H. Choi ◽  
A. Kim ◽  
M. Moinpour ◽  
A. Oehler
Keyword(s):  
Particle Size ◽  
Light Scattering ◽  
Aluminum Content ◽  
Current Method ◽  
Abrasive Particles ◽  
Particle Counts ◽  
Potential Contaminant ◽  
The Impact ◽  
Induced Aggregation ◽  
Wafer Surfaces

AbstractOne of the major drawbacks to CMP is the tendency for abrasive particles in slurries to form aggregates, which have the potential to cause defects on wafer surfaces. Therefore, it is crucial to understand the mechanisms by which aggregates are formed so appropriate metrology can be implemented that will identify defect-causing slurries before they are used in the fab. Single particle optical sensing (SPOS) techniques are commonly used to obtain large particle counts (LPC) for slurries. The SPOS technique requires slurry dilution before measuring and the instrument continues to dilute the sample during a measurement. Other techniques that can be used to characterize slurries are particle size distribution by static light scattering (SLS), mean particle size (MPS) by dynamic light scattering (DLS), and zeta potential (ZP) measurements. Like SPOS, all of these techniques require that slurry be diluted prior to measuring and the current method for doing so is with UPW. Diluted slurry demonstrates significantly different ionic strength than the undiluted slurry, and electrolyte concentration has been shown to affect aggregation and electric double layer characteristics of silica particles 2–6. An alternative diluting solution was formulated that simulates the conductivity and pH of the original slurry to mimic the conditions to which particles are actually exposed. It is crucial to identify the metrology that is compatible with high pH solutions and the impact of these solutions on measurements. A second objective of the study is to examine aluminum contamination in slurries. To date, the aluminum content of silica-based CMP slurries and effects on performance have not been well studied. Aluminum is known as a potential contaminant during abrasive and/or slurry manufacturing processes. Known defect free slurries were doped with aluminum and effects on particle aggregation were observed. Specifically, it is of interest to identify the metrology and techniques that may be useful (and those that are not) in monitoring aluminum induced aggregation.

Radiation Damage Studies with the HVEM

1972 ◽  
Vol 30 ◽  
pp. 680-681
Author(s):  
J. J. Laidler ◽  
B. Mastel
Keyword(s):  
Radiation Damage ◽  
Stainless Steels ◽  
Volume Expansion ◽  
Austenitic Stainless Steels ◽  
Test Facility ◽  
Fast Breeder Reactors ◽  
Breeder Reactors ◽  
Under Construction ◽  
Development Laboratory ◽  
Insight Into

One of the major materials problems encountered in the development of fast breeder reactors for commercial power generation is the phenomenon of swelling in core structural components and fuel cladding. This volume expansion, which is due to the retention of lattice vacancies by agglomeration into large polyhedral clusters (voids), may amount to ten percent or greater at goal fluences in some austenitic stainless steels. From a design standpoint, this is an undesirable situation, and it is necessary to obtain experimental confirmation that such excessive volume expansion will not occur in materials selected for core applications in the Fast Flux Test Facility, the prototypic LMFBR now under construction at the Hanford Engineering Development Laboratory (HEDL). The HEDL JEM-1000 1 MeV electron microscope is being used to provide an insight into trends of radiation damage accumulation in stainless steels, since it is possible to produce atom displacements at an accelerated rate with 1 MeV electrons, while the specimen is under continuous observation.

Microstructural characterization of laser-melted/roller-quenched dicalcium silicate

1988 ◽  
Vol 46 ◽  
pp. 582-583
Author(s):  
C. J. Chan ◽  
K. R. Venkatachari ◽  
W. M. Kriven ◽  
J. F. Young
Keyword(s):  
Particle Size ◽  
Raw Materials ◽  
Shape Change ◽  
Microstructural Characterization ◽  
Particle Size Effect ◽  
Dicalcium Silicate ◽  
Laser Melting ◽  
Uniform Size ◽  
Cell Shape Change ◽  
Wide Range

Dicalcium silicate (Ca2SiO4) is a major component of Portland cement. It has also been investigated as a potential transformation toughener alternative to zirconia. It has five polymorphs: α, α'H, α'L, β and γ. Of interest is the β-to-γ transformation on cooling at about 490°C. This transformation, accompanied by a 12% volume increase and a 4.6° unit cell shape change, is analogous to the tetragonal-to-monoclinic transformation in zirconia. Due to the processing methods used, previous studies into the particle size effect were limited by a wide range of particle size distribution. In an attempt to obtain a more uniform size, a fast quench rate involving a laser-melting/roller-quenching technique was investigated.The laser-melting/roller-quenching experiment used precompacted bars of stoichiometric γ-Ca2SiO4 powder, which were synthesized from AR grade CaCO3 and SiO2xH2O. The raw materials were mixed by conventional ceramic processing techniques, and sintered at 1450°C. The dusted γ-Ca2SiO4 powder was uniaxially pressed into 0.4 cm x 0.4 cm x 4 cm bars under 34 MPa and cold isostatically pressed under 172 MPa. The γ-Ca2SiO4 bars were melted by a 10 KW-CO2 laser.

Analytical Electron Microscopy study of two vehicle-aged automotive exhaust catalysts having dissimilar activities

1989 ◽  
Vol 47 ◽  
pp. 272-273
Author(s):  
Sooho Kim ◽  
M. J. D’Aniello
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Noble Metal ◽  
Catalyst Deactivation ◽  
Analytical Electron Microscopy ◽  
Microscopy Study ◽  
Metal Particles ◽  
Automotive Exhaust ◽  
Exhaust Catalysts ◽  
Analytical Electron

Automotive catalysts generally lose-agtivity during vehicle operation due to several well-known deactivation mechanisms. To gain a more fundamental understanding of catalyst deactivation, the microscopic details of fresh and vehicle-aged commercial pelleted automotive exhaust catalysts containing Pt, Pd and Rh were studied by employing Analytical Electron Microscopy (AEM). Two different vehicle-aged samples containing similar poison levels but having different catalytic activities (denoted better and poorer) were selected for this study.The general microstructure of the supports and the noble metal particles of the two catalysts looks similar; the noble metal particles were generally found to be spherical and often faceted. However, the average noble metal particle size on the poorer catalyst (21 nm) was larger than that on the better catalyst (16 nm). These sizes represent a significant increase over that found on the fresh catalyst (8 nm). The activity of these catalysts decreases as the observed particle size increases.

Sign in / Sign up

Export Citation Format

Share Document