scholarly journals Effect of Tantalum Pentoxide Addition on the Radiopacity Performance of Bi2O3/Ta2O5 Composite Powders Prepared by Mechanical Milling

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7447
Author(s):  
Hsiu-Na Lin ◽  
Chung-Kwei Lin ◽  
Pei-Jung Chang ◽  
Wei-Min Chang ◽  
Alex Fang ◽  
...  
Keyword(s):  
High Temperature ◽  
Cell Viability ◽  
Mechanical Milling ◽  
Setting Time ◽  
High Energy ◽  
Superior Performance ◽  
Face Centered Cubic ◽  
Composite Powders ◽  
Subsequent Formation ◽  
Setting Times

Among the various phases of bismuth oxide, the high temperature metastable face-centered cubic δ phase attracts great attention due to its unique properties. It can be used as an ionic conductor or an endodontic radiopacifying material. However, no reports concerning tantalum and bismuth binary oxide prepared by high energy ball milling and serving as a dental radiopacifier can be found. In the present study, Ta2O5-added Bi2O3 composite powders were mechanically milled to investigate the formation of these metastable phases. The as-milled powders were examined by X-ray diffraction and scanning electron microscopy to reveal the structural evolution. The as-milled composite powders then served as the radiopacifier within mineral trioxide aggregates (i.e., MTA). Radiopacity performance, diametral tensile strength, setting times, and biocompatibility of MTA-like cements solidified by deionized water, saline, or 10% calcium chloride solution were investigated. The experimental results showed that subsequent formation of high temperature metastable β-Bi7.8Ta0.2O12.2, δ-Bi2O3, and δ-Bi3TaO7 phases can be observed after mechanical milling of (Bi2O3)95(Ta2O5)5 or (Bi2O3)80(Ta2O5)20 powder mixtures. Compared to its pristine Bi2O3 counterpart with a radiopacity of 4.42 mmAl, long setting times (60 and 120 min for initial and final setting times) and 84% MG-63 cell viability, MTA-like cement prepared from (Bi2O3)95(Ta2O5)5 powder exhibited superior performance with a radiopacity of 5.92 mmAl (the highest in the present work), accelerated setting times (the initial and final setting time can be shortened to 25 and 40 min, respectively), and biocompatibility (94% cell viability).

scholarly journals EFFECT OF PROCESSING CONDITION AND COMPOSITION ON THE MICROHARDNESS OF Cu-(2.5-10)vol.%Al2O3 NANOCOMPOSITE POWDER PARTICLES PRODUCED BY HIGH ENERGY MECHANICAL MILLING

2010 ◽  
Vol 24 (15n16) ◽  
pp. 2308-2313 ◽  
Author(s):  
AAMIR MUKHTAR ◽  
DELIANG ZHANG ◽  
CHARLIE KONG ◽  
PAUL MUNROE
Keyword(s):  
Dislocation Density ◽  
Mechanical Milling ◽  
Annealing Temperature ◽  
Processing Condition ◽  
High Energy ◽  
Composite Powders ◽  
Heat Treated ◽  
Powder Particles ◽  
Nanocomposite Powders ◽  
Thermal Stability Of

Nanostructured Cu -(2.5-10 vol. %) Al 2 O 3 nanocomposites were produced using high energy mechanical milling. For the as-milled Cu - Al 2 O 3 composite powder particles having Al 2 O 3 volume fractions of 2.5% and 5%, the increase in average microhardness is significant with the increase of milling time from 12 hours to 24 hours. With the increase of the content of Al 2 O 3 nanoparticles the microhardness increases and in the range of 255HV-270HV. The milled nanocomposite powders were heat treated at 150, 300, 400 and 500°C for 1 hour, respectively, to determine the thermal stability of the powder particles as a function of annealing temperature. The average microhardness increased/decreased for the Cu - Al 2 O 3 composites after annealing at 150°C due to the dislocation density, while increasing the annealing temperature to 300°C and 400°C the average microhardness almost remained mostly unchanged. Further increasing the annealing temperature to 500°C causes significant decrease in average microhardness due to reduction in dislocation density and coarsening of Cu grains of the Cu- Al 2 O 3 composite powders produced after 24 hours of milling. This paper is to report and discuss the changes of the microhardness of the material, caused by the compositions and processing conditions, used to fabricate the Cu -(2.5-10) vol. % Al 2 O 3 nanocomposite powders.

The Formation of Coesite under Minimum Static Pressure

2014 ◽  
Vol 675-677 ◽  
pp. 38-41
Author(s):  
De Jun Wang ◽  
Run Ru Liu ◽  
Leng Jing
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Mechanical Milling ◽  
Static Pressure ◽  
High Energy ◽  
Initial Material ◽  
The Earth

Using the α-SiO2 and conducted by high-energy mechanical milling as the initial material, we investigated the synthesis of coesite under high temperature and high pressure in the condition of adding a certain amount of hard Fe fillings. The synthetic samples are measured by XRD and Raman, and the results show that a small amount of small-sized coesite can be obtained under 2.5 GPa. Based on these results, it is considered that the forming depth of natural coesite under the earth is likely to be obviously shallower than that of plate exhumation in the traditional subduction-exhumation hypothesis.

The Cu Matrix Strengthened by TiH2–C In-Situ Synthesized via Mechanical Milling and Spark Plasma Sintering

2021 ◽  
Vol 21 (4) ◽  
pp. 2687-2691
Author(s):  
Nguyen Thi ◽  
Hoang Oanh ◽  
Nguyen Hoang Viet
Keyword(s):  
Spark Plasma Sintering ◽  
Mechanical Milling ◽  
Sintering Temperature ◽  
Annealing Treatment ◽  
High Energy ◽  
Composite Powders ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Tic Nanoparticles

The present work is focused on the fabrication and the investigation of microstructures of copperbased TiC nanocomposites produced by mechanical milling in a high energy planetary ball mill. TiH2, carbon and copper powders were used as starting materials in which In-Situ reaction between carbon and TiH2 occurs to form TiC nanoparticles. The mixture powders of Cu–TiH2–C were milled for 12 h at 450 rpm in Argon gas. Annealing treatment process at 950 °C for 2 h was applied for as-milled composite powders to enhance In-Situ reaction. The consolidation of composite powders was conducted by spark plasma sintering under uniaxial pressing of 70 MPa. Sintering procedure was done at 950 and 1000 °C for 5 min. The results indicated that as TiC nanoparticles are formed after sintering at 950 °C and the TiC particles are increased up at higher sintering temperature of 1000 °C. Fracture surface of sintered samples shows ductile mode. HR-TEM image showed the crystal size of copper was about 10 nm for sample sintered at 1000 °C. The hardness and relative density of the nanocomposites increase when increasing sintering temperature.

The Synthesis from α-SiO2 and Graphite System to Coesite under High Temperature High Pressure

2014 ◽  
Vol 1051 ◽  
pp. 299-302
Author(s):  
De Jun Wang ◽  
Run Ru Liu ◽  
Leng Jing ◽  
Xin Yu Bai
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Carbon Content ◽  
Powder Mixture ◽  
Mechanical Milling ◽  
Graphite Powder ◽  
High Energy ◽  
Mass Ratio ◽  
Synthesis Conditions ◽  
High Temperature High Pressure

Taking α-quartz of different mass ratio mixed with graphite powder mixture as the initial materials, using the method of combining high-energy mechanical milling with high pressure and high temperature , this work inspected the influences of carbon content on the synthesis conditions of coesite. The experimental products were measured by XRD, TEM, and Raman. The results showed that the existence of carbon can obviously inhibit the formation of coesite, and the higher carbon content of initial materials the higher pressure on forming coesite is needed.

scholarly journals Composite Compacts of Fe/Fe3O4 Type Obtained by Mechanical Milling-Sintering-Annealing Route

2015 ◽  
Vol 13 ◽  
pp. 3-8
Author(s):  
Traian Florin Marinca ◽  
Bogdan Viorel Neamţu ◽  
Ionel Chicinaş ◽  
Florin Popa ◽  
Petru Pascuta
Keyword(s):  
Mechanical Milling ◽  
High Energy ◽  
Particle Size Analysis ◽  
Size Analysis ◽  
X Ray Diffraction ◽  
Composite Powders ◽  
Sintered Compact ◽  
X Ray ◽  
Before And After ◽  
Type Composite

Fe/Fe2O3composite powders were obtained by mechanical milling of iron and hematite up to 120 minutes in a high energy planetary ball mill. The particles size decreases by mechanical milling upon the formation of the Fe/Fe2O3composite particles. After 120 minutes of milling the median particles size is at 7.2 μm. The Fe/Fe3O4type composite were obtained by reactive sintering in argon atmosphere at 1100 °C of the Fe/Fe2O3composite powders milled for 60 and 120 minutes. After sintering a FeO-wüstite residual phase is formed and this phase is eliminated by applying a subsequent annealing at a temperature of 550 °C. The sintered compact before and after annealing is composed by a quasi-continuous iron matrix in which are embedded iron oxides clusters (Fe3O4and FeO before annealing and Fe3O4after annealing). The iron oxide clusters are analogous with the Widmanstatten structure observed in steels before and after annealing. The materials have been investigated using laser particle size analysis, optical microscopy, scanning electron microscopy, energy dispersive X-ray spectrometry and X-ray diffraction.

Influence of Milling Time on the Homogeneity of the Al2O3/Ni Composite Powders Obtained by Mechanical Milling

2014 ◽  
Vol 216 ◽  
pp. 146-150 ◽  
Author(s):  
Cristina Voicu ◽  
Florin Popa ◽  
Petru Pascuta ◽  
Ionel Chicinaş
Keyword(s):  
Mechanical Milling ◽  
Milling Time ◽  
High Energy ◽  
X Ray Diffraction ◽  
Nanocomposite Powder ◽  
Composite Powders ◽  
X Ray ◽  
Two Phases ◽  
The Stability ◽  
High Level

Al2O3/Ni nanocomposite powder was obtained by high-energy mechanical milling starting from a mixture of Al2O3 and Ni commercially powders. The Al2O3+15%vol. Ni mixture was homogenized for 15 minutes in the Turbula-type blender and then was milled in a planetary ball mill (Fritsch, Pulverisette 4) under argon atmosphere up to 120 min. Several milling times were used: 10, 30, 60, 90 and 120 minutes respectively. The evolution of the powders during milling and the stability of the composite phases were investigated by X-ray diffraction (XRD), optical microscopy (OM), scanning electron microscopy (SEM) and energy dispersive X-ray microanalysis (EDX). The SEM and OM images show a high level of homogenization of the Ni and Al2O3 phases for milling times larger than 90 minutes. The X-ray studies indicate no mixing between the two phases. The crystallite grain size is decreasing with the milling time.

Nanoparticles Consolidation Mechanism at High Pressure and High Temperature in Diamond-B-Si-Cu System

2012 ◽  
Vol 727-728 ◽  
pp. 334-339
Author(s):  
Ana Lúcia Diegues Skury ◽  
Sérgio Neves Monteiro ◽  
Marcia G. de Azevedo ◽  
Angelica da Cunha dos Santos ◽  
Guerold S. Bobrovnitchii
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Diamond Powder ◽  
High Energy ◽  
Advanced Materials ◽  
Superior Performance ◽  
Wet Milling ◽  
X Ray Diffraction ◽  
Electron Microscopy Analysis ◽  
Microscopy Analysis

The synthesis of advanced materials with superior performance and properties is of growing scientific and technological interest. In particular, significant achievements have been attained in the synthesis of nanocomposites associated with superhard materials. This work investigates nanostructured composites obtained by high pressure and high temperature sintering of synthetic diamond combined with boron, silicon and copper. Diamond powder was mixed with B, Si and Cu, also in the form of powder. The mixture was then submitted to high energy wet milling until a nanopowder was formed. Sintering of this resulting nanopowder was carried out at 5.6 GPa of pressure and 1300°C. X-ray diffraction and scanning electron microscopy analysis revealed the formation of new phases in a well consolidated nanostructure with relatively high density.

In situ TEM Studies of agglomeration of sub-nanometer Ru layers in Ru/C multilayers

1992 ◽  
Vol 50 (1) ◽  
pp. 256-257
Author(s):  
Tai D. Nguyen ◽  
Ronald Gronsky ◽  
Jeffrey B. Kortright
Keyword(s):  
Layered Structure ◽  
Driving Force ◽  
High Energy ◽  
Superior Performance ◽  
In Situ Tem ◽  
Rayleigh Instability ◽  
Practical Applications ◽  
Transmission Electron ◽  
Diffraction Patterns

Nanometer period Ru/C multilayers are one of the prime candidates for normal incident reflecting mirrors at wavelengths < 10 nm. Superior performance, which requires uniform layers and smooth interfaces, and high stability of the layered structure under thermal loadings are some of the demands in practical applications. Previous studies however show that the Ru layers in the 2 nm period Ru/C multilayer agglomerate upon moderate annealing, and the layered structure is no longer retained. This agglomeration and crystallization of the Ru layers upon annealing to form almost spherical crystallites is a result of the reduction of surface or interfacial energy from die amorphous high energy non-equilibrium state of the as-prepared sample dirough diffusive arrangements of the atoms. Proposed models for mechanism of thin film agglomeration include one analogous to Rayleigh instability, and grain boundary grooving in polycrystalline films. These models however are not necessarily appropriate to explain for the agglomeration in the sub-nanometer amorphous Ru layers in Ru/C multilayers. The Ru-C phase diagram shows a wide miscible gap, which indicates the preference of phase separation between these two materials and provides an additional driving force for agglomeration. In this paper, we study the evolution of the microstructures and layered structure via in-situ Transmission Electron Microscopy (TEM), and attempt to determine the order of occurence of agglomeration and crystallization in the Ru layers by observing the diffraction patterns.

NICROFER 5923 HMo-ALLOY 59

Alloy Digest ◽  
1993 ◽  
Vol 42 (5) ◽  
Keyword(s):  
Corrosion Resistance ◽  
High Temperature ◽  
Physical Properties ◽  
Heat Treating ◽  
Face Centered Cubic ◽  
Low Carbon ◽  
High Alloy ◽  
Temperature Performance ◽  
Cubic Structure ◽  
Face Centered

Abstract NICROFER 5923 hMo, often called Alloy 59, was developed with extra low carbon and silicon contents and with a high alloy level of molybdenum to optimize its corrosion resistance. Nicrofer 5923hMo has a face-centered cubic structure. This datasheet provides information on composition, physical properties, elasticity, and tensile properties. It also includes information on high temperature performance as well as forming, heat treating, and joining. Filing Code: Ni-430. Producer or source: VDM Technologies Corporation.

Sign in / Sign up

Export Citation Format

Share Document