Fabrication of AlN Ceramics Using AlN and Nano-Y2O3 Composite Particles Prepared by Mechanical Treatment

2008 ◽  
Vol 403 ◽  
pp. 245-248 ◽  
Author(s):  
Daisuke Hiratsuka ◽  
Junichi Tatami ◽  
Toru Wakihara ◽  
Katsutoshi Komeya ◽  
Takeshi Meguro
Keyword(s):  
Fracture Toughness ◽  
High Performance ◽  
Mechanical Treatment ◽  
Composite Powder ◽  
Composite Particles ◽  
Green Body ◽  
Sintering Aids ◽  
Fine Powders ◽  
Electronic Substrates ◽  
Fractured Surface

AlN ceramics used in electronic substrates and packages are fabricated by the densification of green bodies with sintering aids such as rare-earth oxides. The homogeneous dispersion of the sintering aids, achieved with the help of the mechanochemical bonding of several types of fine powders, is the key process for obtaining a good sinterability and high performance. In this study, we fabricated the AlN ceramics using AlN and nano-Y2O3 composite particles prepared by mechanical treatment. The AlN powder and nano-Y2O3 powder were ball-milled with Al2O3 balls and a dispersant in ethanol in a plastic pot. The powder mixture of AlN and Y2O3 was composited by mechanical treatment. The composite powder was granulated and pressed to obtain a green body. After dewaxing, the AlN green body was fired at 1800°C in 0.6 MPa N2. The sintered body possessed a fracture toughness of 3.6 Pa•m1/2, higher than that, 3.1 Pa•m1/2, of the AlN ceramics fabricated without the mechanical treatment. An observation of the fractured surface revealed that grain boundary reinforcement enhances the fracture toughness of the AlN ceramics made of composite particles.

MECHANO-CHEMICAL PREPARATION OF POWDER QUARTZ/TiO2 COMPOSITE PARTICLES

2013 ◽  
Vol 20 (02) ◽  
pp. 1350016 ◽  
Author(s):  
GAO-XIANG DU ◽  
HAO HE ◽  
LI-BING LIAO ◽  
LI-JUAN WANG
Keyword(s):  
Titanium Dioxide ◽  
Chemical Reaction ◽  
Thermodynamic Calculation ◽  
High Performance ◽  
Chemical Method ◽  
Composite Powder ◽  
Composite Particles ◽  
Chemical Preparation ◽  
White Pigment ◽  
Core Powder

Titanium dioxide pigment is a white pigment of high performance. However, its production could cause severe environmental and resource problems. In this paper, powder quartz/ TiO2 composite particles (PQ/TCP), a type of core (powder quartz)–shell( TiO2 ) composite powder, were prepared by a mechano-chemical method. The pigment properties of PQ/TCP and the mechanism of the mechano-chemical reaction between quartz and TiO2 were investigated. Orthogonal analyses of experimental vairables showed optimal pigment characteristics of PQ/TCP under the following conditions: 4 h of activation for powder quartz, mixing/grinding at 1000 rpm for 1 h, with a mixing slurry made of 50% powder quartz and 0.4% dispersant. Powder quartz was evenly coated by TiO2 and the Si–O–Ti bond was formed between powder quartz and TiO2 in PQ/TCP as revealed by FTIR analyses and confirmed by surface thermodynamic calculation.

Microstructure Analysis of the ZrO2/Al2O3 Multi-Phase Ceramics

2013 ◽  
Vol 544 ◽  
pp. 191-195
Author(s):  
Zhi Wei Chen ◽  
Jin Ye Niu ◽  
Liu Feng ◽  
Dong Wu Liu ◽  
Xiao Bing Wei
Keyword(s):  
Fracture Toughness ◽  
High Performance ◽  
Normal Pressure ◽  
Xrd Analysis ◽  
Cold Isostatic Pressing ◽  
Sintering Aids ◽  
Toughening Mechanism ◽  
Mapping Analysis ◽  
Different Temperatures ◽  
Multi Phase

Scanning electron microscopy (SEM) with X-ray mapping analysis was applied to systematically study the microstructure of ZrO2/Al2O3 multi-phase (ZTA) ceramics prepared by firstly cold isostatic pressing of the as-prepared powders with different formulas and then normal pressure sintering of green bodies at different temperatures, which was proposed to illustrate the toughening mechanism of ZrO2 phase as well as the effect of the microstructure on the fracture toughness of the ZTA ceramics. In addition, XRD analysis was carried out to characterize the phase composition and validate the mapping data from microanalysis. Results obtained in this study demonstrate that the amount of sintering aids added to decrease the sintering temperatures as well as the distribution of ZrO2 particles in Al2O3 particles both play key roles in the microstructure and fracture toughness of ZTA ceramics, which indicates that microanalysis have important directive to the preparation of multi-phase ceramics with high performance.

ARMCO PH 13-8Mo

Alloy Digest ◽  
1990 ◽  
Vol 39 (2) ◽  
Keyword(s):  
Fracture Toughness ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Physical Properties ◽  
Stress Corrosion ◽  
Tensile Properties ◽  
High Performance ◽  
High Strength ◽  
Heat Treating ◽  
Temperature Performance

Abstract ARMCO PH 13-8Mo is designed for high-performance applications requiring high strength coupled with excellent resistance to corrosion and stress corrosion. It has excellent toughness, good transverse properties and excellent forgeability. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on low and high temperature performance, and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SS-224. Producer or source: Baltimore Specialty Steels Corporation. Originally published May 1969, revised February 1990.

BETHLEHEM LUKENS PLATE HPS-70W

Alloy Digest ◽  
2000 ◽  
Vol 49 (12) ◽  
Keyword(s):  
Fracture Toughness ◽  
Corrosion Resistance ◽  
Tensile Properties ◽  
High Performance ◽  
Iron And Steel ◽  
Cooperative Agreement ◽  
Federal Highway ◽  
High Performance Steel ◽  
Department Of The Navy ◽  
Steel Institute

Abstract BETHLEHEM LUKENS PLATE HPS-70W is a high-performance steel (HPS) developed through a cooperative agreement among the Federal Highway Administration (FHWA), the American Iron and Steel Institute (AISI), and the Department of the Navy. This steel is an improved version of ASTM A 709 grade 70W. This datasheet provides information on composition and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as forming and joining. Filing Code: SA-506. Producer or source: Bethlehem Lukens Plate.

OUTOKUMPU TYPE 630

Alloy Digest ◽  
2016 ◽  
Vol 65 (2) ◽  
Keyword(s):  
Fracture Toughness ◽  
Stainless Steel ◽  
Corrosion Resistance ◽  
Physical Properties ◽  
High Performance ◽  
High Strength ◽  
Heat Treating ◽  
304 Stainless Steel ◽  
Type 304 ◽  
Type 304 Stainless Steel

Abstract Outokumpu Type 630 is a martensitic age hardenable alloy of composition 17Cr-4Ni. The alloy has high strength and corrosion resistance similar to that of Type 304 stainless steel. This datasheet provides information on composition, physical properties, hardness, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as forming, heat treating, and joining. Filing Code: SS-1238. Producer or source: Outokumpu High Performance Stainless.

VANADIS 4

Alloy Digest ◽  
1991 ◽  
Vol 40 (10) ◽  
Keyword(s):  
Fracture Toughness ◽  
Powder Metallurgy ◽  
Physical Properties ◽  
Tool Steel ◽  
High Performance ◽  
Cold Work ◽  
Heat Treating ◽  
Good Combination ◽  
Bend Strength ◽  
Cold Work Tool Steel

Abstract VANADIS 4 is a high performance cold work tool steel made by powder metallurgy. It offers an extremely good combination of resistance and toughness for high performance tools. This datasheet provides information on composition, physical properties, hardness, elasticity, and bend strength as well as fracture toughness. It also includes information on heat treating and machining. Filing Code: TS-506. Producer or source: Uddeholm Corporation.

Fracture Toughness of Large Forgings for Power Producing Industry

2013 ◽  
Vol 577-578 ◽  
pp. 593-596 ◽  
Author(s):  
Václav Mentl
Keyword(s):  
Fracture Toughness ◽  
Chemical Composition ◽  
Steam Turbine ◽  
Mechanical Treatment ◽  
Material Degradation ◽  
The Real ◽  
Operational Safety ◽  
Local Properties ◽  
Thermo Mechanical Treatment ◽  
Shape And Size

The steam turbine rotors represent large components both in radial and axial directions. Their local properties generally differ from one forging to another, or if we compare head and bottom parts of the original ingot, or central and circumferential localities of one rotor body respectively, or if we compare the properties of separate discs e.g. in the case of welded rotors. These differences stem from both even slight changes in the chemical composition (of separate heats or even within one ingot) and thermo-mechanical treatment and in the differences in technology with respect to the real shape and size of the forgings in question. In the paper, the consequences of the differences in fracture toughness characteristics in various rotor localities are discussed with respect to the rotors operational safety taking into account the existence of cracks and material degradation.

Thermal properties of polybenzoxazine exhibiting improved toughness: Blending with cyclodextrin and its derivatives

2021 ◽  
pp. 095400832110130
Author(s):  
Hailong Li ◽  
Sipei Zhao ◽  
Li Pei ◽  
Zihe Qiao ◽  
Ding Han ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Hydrogen Bonds ◽  
High Performance ◽  
Practical Application ◽  
Scanning Calorimetry ◽  
Thermoset Resins ◽  
Chemical Structures ◽  
Microscopy Techniques ◽  
Fractured Surface ◽  
Scanning Electron

Polybenzoxazines are emerging as a class of high-performance thermoset polymers that can find their applications in various fields. However, its practical application is limited by its low toughness. The cyclic β-cyclodextrin and a newly synthesized derivative (β-cyclodextrin-MAH) were separately blended with benzoxazine to improve the toughness of polybenzoxazine. The results revealed that the maximum impact strength of the blend was 12.24 kJ·m−2 and 14.29 kJ·m−2 when 1 wt.% of β-Cyclodextrin and β-Cyclodextrin-MAH, respectively, were used. The strengths were 53% and 86% higher than that of pure polybenzoxazine. The curing reaction, possible chemical structures, and fractured surface were examined using differential scanning calorimetry, Fourier transform infrared spectroscopy, and scanning electron microscopy techniques to understand the mechanism of generation of toughness. The results revealed that the sea-island structure and the presence of hydrogen bonds between polybenzoxazine and β-cyclodextrin and β-cyclodextrin-MAH resulted in the generation of toughness. Furthermore, the curves generated during thermogravimetric analysis did not significantly change, revealing the good thermal properties of the system. The phase-separated structure and the hydrogen bonds present in the system can be exploited to prepare synergistically tough polybenzoxazine exhibiting excellent thermal properties. This can be a potential way of modifying the thermoset resins.

Nano Carbon/Vertical Graphene/MnO 2 Nanosheets Composite Particles for High‐Performance Supercapacitors

2022 ◽  
pp. 2100884
Author(s):  
Shiwen Li ◽  
Junsheng Lin ◽  
Lei Zhao ◽  
Zhonghua Ren ◽  
Jie Yu
Keyword(s):  
High Performance ◽  
Composite Particles ◽  
Nano Carbon

Characterization of Fe3O4@CS@NMDP magnetic nanoparticles with core–shell structure prepared by chemical cross-linking method

2017 ◽  
Vol 10 (05) ◽  
pp. 1750056 ◽  
Author(s):  
Huiping Shao ◽  
Jiangcong Qi ◽  
Tao Lin ◽  
Yuling Zhou ◽  
Fucheng Yu
Keyword(s):  
Magnetic Nanoparticles ◽  
Shell Structure ◽  
High Performance ◽  
Cross Linking ◽  
Composite Particles ◽  
Core Shell ◽  
The Core ◽  
Targeting Delivery ◽  
Core Shell Structure ◽  
Chemical Cross Linking

The core–shell structure composite magnetic nanoparticles (NPs), Fe3O4@chitosan@nimodipine (Fe3O4@CS@NMDP), were successfully synthesized by a chemical cross-linking method in this paper. NMDP is widely used for cardiovascular and cerebrovascular disease prevention and treatment, while CS is of biocompatibility. The composite particles were characterized by an X-ray diffractometer (XRD), a Fourier transform infrared spectroscopy (FT-IR), a transmission electron microscopy (TEM), a vibrating sample magnetometers (VSM) and a high performance liquid chromatography (HPLC). The results show that the size of the core–shell structure composite particles is ranging from 12[Formula: see text]nm to 20[Formula: see text]nm and the coating thickness of NMDP is about 2[Formula: see text]nm. The saturation magnetization of core–shell composite NPs is 46.7[Formula: see text]emu/g, which indicates a good potential application for treating cancer by magnetic target delivery. The release percentage of the NMDP can reach 57.6% in a short time of 20[Formula: see text]min in the PBS, and to 100% in a time of 60[Formula: see text]min, which indicates the availability of Fe3O4@CS@NMDP composite NPs for targeting delivery treatment.

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