SYNTHESIS AND CHARACTERIZATION OF Si3N4@Al(OH)3–Y(OH)3 CORE-SHELL COMPOSITE PARTIC3LES

2008 ◽  
Vol 15 (05) ◽  
pp. 581-585 ◽  
Author(s):  
JIE-GUANG SONG ◽  
GANG-CHANG JI ◽  
SHI-BIN LI ◽  
LIAN-MENG ZHANG
Keyword(s):  
High Temperature ◽  
High Performance ◽  
Ceramic Materials ◽  
Composite Particles ◽  
Core Shell ◽  
High Temperature Strength ◽  
Bet Analysis ◽  
Co Precipitation ◽  
Shell Composite

Silicon nitride ( Si 3 N 4) has attracted substantial interest because of its extreme chemical and physical properties, but the sintering densification of Si 3 N 4 is difficult, and it is easily oxidized in the high-temperature air to impact high-temperature strength, which restricts its applied range. In order to decrease the oxidization and improve the strength of Si 3 N 4 at high temperature, the surface of Si 3 N 4 is coated with Al ( OH )3 and Y ( OH )3 to synthesis Si 3 N 4@ Al ( OH )3– Y ( OH )3 core-shell composite particles. Through TEM, XRD, and BET analysis, when pH is about 9, Si 3 N 4@ Al ( OH )3– Y ( OH )3 core-shell composite particles are successfully synthesized by co-precipitation methods. Coating layer is about 200 nm, which is compaction and conformability. Dispersion of coated Si 3 N 4 with Al ( OH )3 and Y ( OH )3 particles are very good. Synthesis of Si 3 N 4@ Al ( OH )3– Y ( OH )3 core-shell composite powder will lay the foundation for preparing high-performance YAG/Si 3 N 4 multiphase ceramic materials.

THERMODYNAMIC AND KINETIC ANALYSES OF SYNTHESIZING ZrB2@Al(OH)3–Y(OH)3 CORE–SHELL COMPOSITE PARTICLES

2007 ◽  
Vol 14 (01) ◽  
pp. 117-122 ◽  
Author(s):  
JIEGUANG SONG ◽  
LIANMENG ZHANG ◽  
JUNGUO LI ◽  
JIANRONG SONG
Keyword(s):  
High Temperature ◽  
High Performance ◽  
Solubility Product ◽  
Ceramic Materials ◽  
Precipitation Method ◽  
Composite Particles ◽  
Core Shell ◽  
High Temperature Strength ◽  
Co Precipitation ◽  
Shell Composite

ZrB 2 has some excellent performances, but it is easily oxidized at high temperatures to impact the high-temperature strength, which restricts its applied range. To protect from the oxidization and improve the strength of ZrB 2 at high temperature, the surface of ZrB 2 particles is coated with the Al ( OH )3– Y ( OH )3 shell to synthesize ZrB 2@ Al ( OH )3– Y ( OH )3 core–shell composite particles. Through the thermodynamic and kinetic analyses of the heterogeneous nucleation and homogeneous nucleation, the concentration product of precursor ion ( Y 3+ or Al 3+) and OH - (Qi) must be greater than the solubility product (K sp ), respectively; the conditions of Y 3+ and Al 3+ are reached to produce Al ( OH )3– Y ( OH )3 shell on the ZrB 2 surface between the Y 3+ line and the AlO 2- line. Through TEM and XRD analyses, ZrB 2@ Al ( OH )3– Y ( OH )3 core–shell composite particles are successfully synthesized by the co-precipitation method, the shell layer quality is better at pH = 9, which established the foundation for preparing high-performance YAG / ZrB 2 and Al 2 O 3– YAG / ZrB 2 multiphase ceramic materials.

Synthesis Mechanism of ZrB2@A12O3-Y2O3 Composite Powders with Core-Shell Microstructure

2016 ◽  
Vol 680 ◽  
pp. 133-136 ◽  
Author(s):  
Jie Guang Song ◽  
Da Ming Du ◽  
Fang Wang ◽  
Ming Han Xu ◽  
Shi Bin Li ◽  
...  
Keyword(s):  
High Temperature ◽  
Sintering Temperature ◽  
Precipitation Method ◽  
Core Shell ◽  
High Temperature Strength ◽  
Shell Microstructure ◽  
Composite Powders ◽  
Synthesis Mechanism ◽  
Co Precipitation ◽  
Shell Composite

ZrB2 has some excellent high-temperature performance. However, due to it is easily oxidized in the high-temperature air to impact high-temperature strength, which restricts its applied range. To decrease the oxidization and sintering temperature, and improve the strength of ZrB2 at high temperature, in this paper, the prepared composite powders is analyzed with XRD, SEM, EDS and TEM, which proves ZrB2@A12O3-Y2O3 core-shell composite powders are successfully synthesized by co-precipitation method, the synthesis mechanism of ZrB2@A12O3-Y2O3 core-shell composite powders is received through the results discussion.

INFLUENCE OF DISPERSION ON COATING EFFECT OF ZrB2@Al(OH)3–Y(OH)3 CORE-SHELL COMPOSITE PARTICLES

2009 ◽  
Vol 16 (02) ◽  
pp. 231-239
Author(s):  
JIE-GUANG SONG ◽  
YANG-LIANG LI ◽  
GANG-CHANG JI ◽  
DA-MING DU ◽  
MING-HAN XU ◽  
...  
Keyword(s):  
High Temperature ◽  
Composite Shell ◽  
Composite Particles ◽  
Core Shell ◽  
Coating Process ◽  
Ultrasonic Dispersion ◽  
Shell Composite ◽  
Coating Ratio ◽  
Better Than

ZrB 2 are widely applied because of some excellent performances; however, ZrB 2 is easily oxidized in the high-temperature air. To reach better Al ( OH )3– Y ( OH )3 composite shell and higher coating ratio on the ZrB 2 particles surfaces, ZrB 2 particles must be adequately dispersed in the ZrB 2 suspension during the coating process. The dispersion of ZrB 2 particles and the influence of dispersion on coating effect of ZrB 2@ Al ( OH )3– Y ( OH )3 core-shell composite particles were investigated. The dispersion of ZrB 2 suspension adding the polyelectrolyte dispersant is better than that of ZrB 2 suspension adding the nonionic dispersant; the dispersant content is 2 vol% of ZrB 2 suspension to reach the best dispersion. The best dispersion is obtained by the ultrasonic dispersion for 10 min. ZrB 2 particles are coated using the dispersant and the ultrasonic dispersion in the ZrB 2 suspension to obtain the better coating effect. The dispersion of ZrB 2 particles is increased with increasing the coating content.

Synthesis and characterization of silica–silver core–shell composite particles with uniform thin silver layers

2007 ◽  
Vol 180 (10) ◽  
pp. 2871-2876 ◽  
Author(s):  
Shaochun Tang ◽  
Yuefeng Tang ◽  
Shaopeng Zhu ◽  
Haiming Lu ◽  
Xiangkang Meng
Keyword(s):  
Synthesis And Characterization ◽  
Composite Particles ◽  
Core Shell ◽  
Shell Composite ◽  
Silver Core

Scalable construction of heteroatom-doped and hierarchical core–shell MnO2 nanoflakes on mesoporous carbon for high performance supercapacitor devices

2020 ◽  
Vol 7 (2) ◽  
pp. 411-420
Author(s):  
Xue Bai ◽  
Dianxue Cao ◽  
Hongyu Zhang
Keyword(s):  
Mesoporous Carbon ◽  
High Performance ◽  
High Energy ◽  
Cycling Stability ◽  
Core Shell ◽  
Power Densities ◽  
Shell Composite ◽  
Asymmetric Device

Combining interfacial methods and mesoporous carbon channels, an asymmetric device, using N,S-codoped mesoporous carbon and a MnO2@MC-30 core shell composite, is assembled with high energy, power densities and outstanding cycling stability.

scholarly journals Achieving high strength and ductility in ODS-W alloy by employing oxide@W core-shell nanopowder as precursor

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Zhi Dong ◽  
Zongqing Ma ◽  
Liming Yu ◽  
Yongchang Liu
Keyword(s):  
High Temperature ◽  
Metal Matrix ◽  
High Performance ◽  
High Energy ◽  
Core Shell ◽  
Microstructural Stability ◽  
Oxide Particles ◽  
Ods Alloy ◽  
Prepared Alloy ◽  
Strength And Ductility

AbstractWith excellent creep resistance, good high-temperature microstructural stability and good irradiation resistance, oxide dispersion strengthened (ODS) alloys are a class of important alloys that are promising for high-temperature applications. However, plagued by a nerve-wracking fact that the oxide particles tend to aggregate at grain boundary of metal matrix, their improvement effect on the mechanical properties of metal matrix tends to be limited. In this work, we employ a unique in-house synthesized oxide@W core-shell nanopowder as precursor to prepare W-based ODS alloy. After low-temperature sintering and high-energy-rate forging, high-density oxide nanoparticles are dispersed homogeneously within W grains in the prepared alloy, accompanying with the intergranular oxide particles completely disappearing. As a result, our prepared alloy achieves a great enhancement of strength and ductility at room temperature. Our strategy using core-shell powder as precursor to prepare high-performance ODS alloy has potential to be applied to other dispersion-strengthened alloy systems.

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