Hot Press Sintering Behavior of Nano-Sized AlN Powders

2010 ◽  
Vol 105-106 ◽  
pp. 720-722
Author(s):  
Hong Bo Li ◽  
Jun Ting Luo ◽  
Yong Fei Gu ◽  
Yan Xia Xu
Keyword(s):  
Grain Size ◽  
Relative Density ◽  
Elevated Temperatures ◽  
Sintering Temperature ◽  
Hexagonal Wurtzite Structure ◽  
Sintering Behavior ◽  
Mechanical Resistance ◽  
Hot Press ◽  
Average Grain Size ◽  
Hot Press Sintering

Aluminum nitride (AlN) is a stoichiometric compound with the hexagonal wurtzite structure. AlN has excellent thermal conductivity and good properties as electronic insulator. It displays good mechanical resistance up to elevated temperatures and is resistant against corrosion by molten metals. Bulk AlN may therefore be used as a refractory structural material as well as a substrate for high power microelectronic devices. However, it is very difficult for sintering high-density AlN at lower temperature than 1800°C. Nano-sized AlN powders were sintered by hot press sintering at low temperature of 1500~1700°C and mechanical properties were investigated. β-AlN and β-Al2O3 were detected when the sintering temperature is 1600°C. The phase transition β-AlN to α-AlN was discovered at a 1700°C sintering temperature. Relative density and average grain size were increasing with the increasing of sintering temperature, and fracture form is intercrystalline crack in 1500°C and transcrystalline crack in 1700°C. 97.3% relative density and 850nm average grain size were deserved at 1700°C.

Effect of Iron Additive on the Sintering Behavior of Hot-Pressed ZrC-W Composites

2008 ◽  
Vol 368-372 ◽  
pp. 1764-1766 ◽  
Author(s):  
Yu Jin Wang ◽  
Lei Chen ◽  
Tai Quan Zhang ◽  
Yu Zhou
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Relative Density ◽  
Sintering Temperature ◽  
Sintering Behavior ◽  
Hot Press ◽  
Sintering Additive ◽  
Microstructure And Mechanical Properties ◽  
Hot Press Sintering

The ZrC-W composites with iron as sintering additive were fabricated by hot-press sintering. The densification, microstructure and mechanical properties of the composites were investigated. The incorporation of Fe beneficially promotes the densification of ZrC-W composites. The relative density of the composite sintered at 1900°C can attain 95.3%. W2C phase is also found in the ZrC-W composite sintered at 1700°C. The content of W2C decreases with the increase of sintering temperature. However, W2C phase is not identified in the composite sintered at 1900°C. The flexural strength and fracture toughness of the composites are strongly dependent on sintering temperature. The flexural strength and fracture toughness of ZrC-W composite sintered at optimized temperature of 1800°C are 438 MPa and 3.99 MPa·m1/2, respectively.

Hot Press Sintering and Superplastic Forming of Fine-Grained Si3N4-Si2N2O Composites

2006 ◽  
Vol 532-533 ◽  
pp. 25-28 ◽  
Author(s):  
Qing Zhang ◽  
Jun Ting Luo ◽  
Kai Feng Zhang
Keyword(s):  
Grain Size ◽  
Complex Shape ◽  
Sintering Temperature ◽  
Superplastic Forming ◽  
Hot Press ◽  
Fine Grained ◽  
Sinter Forging ◽  
Average Grain Size ◽  
Hot Press Sintering

Si3N4- Si2N2O composites were fabricated with amorphous nano-sized silicon nitride powders by the hot press sintering(HPS). The Si2N2O phase was generated by an in-situ reaction 2Si3N4(s)+1.5O2(g)=3Si2N2O(s)+N2(g). The content of Si2N2O phase up to 60% was accepted when the sintering temperature was 1650°C and decreased whether the sintering temperature was increased or not, which indicated that the reaction was reversible. The mass loss, relative density and average grain size increased with raising of sintering temperature. The average grain size was less than 500nm if the sintering temperature was below 1700°C. The sintered body crystaled completely at 1600°C . The microstructure crystaled in 1600°C indicated that most of the grain size was in 150-250nm. The aspect ratio of some grains reached 1.5. The superplastic deep-drawing forming could be undertaken at 1550°C with a forming velocity of 0.2mm/min. The complex-shape gears could be formed by a sinter-forging technology when the sintering temperature was 1600°C and the superplastic forging temperature was 1550°C.

The Structure-Property-Processing Relationship for Sintered Yttria-Stabilized Zirconia (YSZ)/Alumina Bioceramics

2013 ◽  
Vol 25 (04) ◽  
pp. 1350005 ◽  
Author(s):  
Sea-Fue Wang ◽  
Thomas Chung-Kuang Yang ◽  
Ya-Ting Hsu ◽  
Sheng-Yang Lee ◽  
Jen-Chang Yang
Keyword(s):  
Fracture Toughness ◽  
Relative Density ◽  
Sintering Temperature ◽  
High Hardness ◽  
Solid State Reaction Method ◽  
Sintering Behavior ◽  
Structure Property ◽  
Stabilized Zirconia ◽  
Average Grain Size ◽  
Alumina Addition

The objective of this research is to study the effects of alumina addition on the microstructure-mechanical property relationship and sintering behavior of yttria (3 mol%)-stabilized zirconia (YSZ) ceramics. Well-dispersed YSZ / Al 2 O 3 ceramics containing 10–40 wt.% Al 2 O 3 were prepared by solid state reaction method. The relative density, average grain size, lattice parameters, microhardness, and fracture toughness of YSZ / Al 2 O 3 ceramics system sintered in the temperature range of 1250~1500°C as a function of Al 2 O 3 content were investigated. Experimental results showed that the ceramics with high Al 2 O 3 content and low sintering temperature tended to reveal low bulk densities. But the Al 2 O 3 content dependence on relative density for YSZ / Al 2 O 3 ceramics becomed deminishing when increasing the sintering temperature. Dense ceramics with composition of (80/20) ( YSZ / Al 2 O 3) and sintered at temperature of 1400°C and 1450°C revealed the optimal Vickers hardness and fracture toughness properties. These ceramics with high Al 2 O 3 content tended to reveal small grain sizes. The high sintering temperature governs the slow grain growth and high hardness in materials indicating the good correlation between microstructure of fabricated dense and mechanical properties.

On the Performance of 17Ni/(10NiO-NiFe2O4) Cermet by Hot-Press Sintering Technology: Sintering Temperature Effects

2013 ◽  
Vol 457-458 ◽  
pp. 152-155
Author(s):  
Wen Zheng Dong ◽  
Qi Quan Lin ◽  
Tao Jiang ◽  
Zhi Gang Wang
Keyword(s):  
Mechanical Properties ◽  
Bending Strength ◽  
Sintering Temperature ◽  
Raw Materials ◽  
Great Influence ◽  
Sintering Behavior ◽  
Hot Press ◽  
Three Point Bending ◽  
Strength Tests ◽  
Hot Press Sintering

The sintering behavior and the resulting of cermet are influenced not only by the characteristics and impurities of the raw materials but also are found to be dependent on the thermal history during the fabrication process. Our work is concerned with the effect of sintering temperature on the mechanical properties of 17Ni/(10NiO-NiFe2O4) cermet. The nickel ferrite based cermet were prepared by hot-press sintering technology at 16MPa and sintered at temperatures ranging from 900 to 1200°C. The microstructure, phase compositions and mechanical properties were studied by SEM, XRD and three point bending strength tests respectively. It has been found that, the relative density, hardness and bending strength of NiFe2O4 based cermet have a great influence upon the sintering temperature, and an optimal sintering temperature, e.g. 1100°C is chosen through our experiments. The highest bending strength of 125.89Mpa could be obtained under the sintering temperature of 1100°C. Meanwhile, the thermal shock resistance increases as the sintering temperature increases.

Hot-Press Sintering of the W-40wt.%Cu Composite Tape-Casting Film

2017 ◽  
Vol 727 ◽  
pp. 966-971
Author(s):  
Chuan Bin Wang ◽  
Kong Fei Sun ◽  
Guo Qiang Luo ◽  
Jian Zhang ◽  
Qiang Shen ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Relative Density ◽  
Vickers Hardness ◽  
Bending Strength ◽  
Sintering Temperature ◽  
Tape Casting ◽  
Hot Press ◽  
Composite Tape ◽  
Mechanical And Electrical Properties ◽  
Hot Press Sintering

In this research, the W-40wt.%Cu composite tape-casting films were prepared through the vacuum hot-press sintering method, and the effect of sintering temperature on the microstructures and properties of the W-40wt.%Cu composite samples was studied. Microstructures of the W-40wt.%Cu tape-casting film and the prepared samples were analyzed by field emission scanning electron microscopy (FE-SEM). The phase of the samples was investigated by X-ray diffraction (XRD). The relative density, Vickers hardness, bending strength and electrical conductivity of the samples were investigated. The results show that the relative density of the W-40wt.%Cu composite materials enhances with the increasing of the sintering temperature, at the same time the mechanical and electrical properties are better with the increasing of the sintering temperature. The W-40wt.%Cu composites prepared at the condition of 900°C-200MPa-2h have the relative density of 97%, the bending strength of 507.3MPa, the Vickers hardness of 376.2HV and the electrical conductivity of 32.5% IACS, respectively.

Spark Plasma Sintering of Two Commercial Al2O3 Powders

2011 ◽  
Vol 412 ◽  
pp. 336-339 ◽  
Author(s):  
Zhen Hua Liu ◽  
Qin Ma ◽  
Jin Jun Lu
Keyword(s):  
Grain Size ◽  
Relative Density ◽  
Spark Plasma Sintering ◽  
Sintering Temperature ◽  
Plasma Sintering ◽  
Average Grain Size ◽  
Spark Plasma

Al2O3 ceramic is prepared by spark plasma sintering (SPS) using two commercial α-Al2O3 powders at elevated sintering temperature. The relative density and average grain size of the prepared Al2O3 ceramics are measured and compared. One α-Al2O3 powder has good sintering property because the relative density of the prepared α-Al2O3 ceramic is higher than 97% while another α-Al2O3 powder has poor sintering property.

scholarly journals A Comparative Study of Spark Plasma and Conventional Sintering of Undoped SnO2 Sputtering Targets

2021 ◽  
Author(s):  
Levent Koroglu ◽  
Cem Aciksari ◽  
Erhan Ayas ◽  
Emel Ozel ◽  
Ender Suvaci
Keyword(s):  
Grain Size ◽  
Relative Density ◽  
Dwell Time ◽  
Sintering Temperature ◽  
Phase Evolution ◽  
Microstructural Development ◽  
Plasma Sintering ◽  
Average Grain Size ◽  
Conventional Sintering ◽  
Spark Plasma

Abstract SnO2 ceramics were fabricated by spark plasma sintering (SPS) and conventional (pressureless) sintering techniques by using undoped submicron SnO2 powders. The effect of sintering temperature and dwell time on the densification behavior, phase evolution and microstructural development of sintered ceramics were investigated. The relative density of SPSed ceramics increased when dwell time was raised from 1 to 10 min at 950ºC. However, full densification was prevented by the decomposition of SnO2 to Sn and O2(g). The decomposition starts after ~ 10 min at 950ºC. In parallel to this observations, as sintering temperature increases, amount of the elemental Sn in agglomerated form increases. On the other hand, the relative densities of conventionally sintered ceramics (at 1200ºC-1400ºC) were relatively low (i.e., 63 % relative density), and abnormal grain growth was observed due to the shift in sintering mechanisms to evaporation-condensation as a dominant mechanism. Since the undoped SnO2 ceramics, SPSed at 950°C for 5 min under 30 MPa exhibit 93 % relative density, high chemical purity, homogeneous grain size distribution and smaller average grain size, they demonstrate great potential as sputtering targets for production of high-quality thin film gas sensors.

Liquid Phase Sintering Behavior of Amorphous Nano-Sized Silicon Nitride Powders

2007 ◽  
Vol 336-338 ◽  
pp. 1069-1071 ◽  
Author(s):  
H.B. Li ◽  
Jun Ting Luo ◽  
Kai Feng Zhang
Keyword(s):  
Grain Size ◽  
Silicon Nitride ◽  
Liquid Phase ◽  
Sintering Temperature ◽  
Liquid Phase Sintering ◽  
Sintering Behavior ◽  
Average Grain Size ◽  
Sintering Method ◽  
Amorphous Si3n4

The amorphous nano-sized silicon nitride powders were sintered by liquid phase sintering method. Si3N4-Si2N2O composites were in-situ fabricated. The Si2N2O phase was generated by an in-situ reaction 2Si3N4(s)+1.5O2(g)=3Si2N2O(s)+N2(g). The content of Si2N2O phase up to 60% was obtained at a sintering temperature of 1650°C and reduced when the sintering temperature increased or decreased, which indicates that the reaction is reversible. The mass loss, relative density and average grain size increase with increasing of sintering temperature. The average grain size is less than 500nm when the sintering temperature is below 1700°C. During the sintering procedure, there is a complex crystallization and phase transition: amorphous Si3N4 → equiaxial α-Si3N4→ equiaxial β-Si3N4 → rod-likeSi2N2O → needle-like β-Si3N4. Small round-shaped β-Si3N4 particles are entrapped in the Si2N2O grains and a high density of staking faults are situated in the middle of Si2N2O grains at a sintering temperature of 1650°C.

scholarly journals Effect of Vanadium Reinforcement on the Microstructure and Mechanical Properties of Magnesium Matrix Composites

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 806
Author(s):  
Liqing Sun ◽  
Shuai Sun ◽  
Haiping Zhou ◽  
Hongbin Zhang ◽  
Gang Wang ◽  
...  
Keyword(s):  
Grain Size ◽  
Grain Refinement ◽  
Milling Process ◽  
Mg Alloy ◽  
Matrix Composites ◽  
Magnesium Matrix Composites ◽  
Pinning Effect ◽  
Average Grain Size ◽  
The Matrix ◽  
Hot Press Sintering

In this work, vanadium particles (VP) were utilized as a novel reinforcement of AZ31 magnesium (Mg) alloy. The nanocrystalline (NC) AZ31–VP composites were prepared via mechanical milling (MM) and vacuum hot-press sintering. During the milling process, the presence of VP contributed to the cold welding and fracture mechanism, resulting in the acceleration of the milling process. Additionally, increasing the VP content accelerated the grain refinement of the matrix during the milling process. After milling for 90 h, the average grain size of AZ31-X wt % Vp (X = 5, 7.5, 10) was refined to only about 23 nm, 19 nm and 16 nm, respectively. In the meantime, VP was refined to sub-micron scale and distributed uniformly in the matrix, exhibiting excellent interfacial bonding with the matrix. After the sintering process, the average grain size of AZ31-X wt % VP (X = 5, 7.5, 10) composites still remained at the NC scale, which was mainly caused by the pinning effect of VP. Besides that, the porosity of the sintered composites was no more than 7.8%, indicating a good densification effect. As a result, there was little difference between the theoretical and real density. Compared to as-cast AZ31 Mg alloy, the microhardness of sintered AZ31-X wt % VP (X = 5, 7.5, 10) composites increased by 65%, 87% and 96%, respectively, owing to the strengthening mechanisms of grain refinement strengthening, Orowan strengthening and load-bearing effects.

scholarly journals Effect of Sintering Temperature on Microstructure and Mechanical Properties of Hot-Pressed Fe/FeAl2O4 Composite

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 422
Author(s):  
Kuai Zhang ◽  
Yungang Li ◽  
Hongyan Yan ◽  
Chuang Wang ◽  
Hui Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Bending Strength ◽  
Sintering Temperature ◽  
Raw Materials ◽  
Hot Press ◽  
Microstructure And Mechanical Properties ◽  
Powder Particles ◽  
Hot Press Sintering ◽  
Sintering Method

An Fe/FeAl2O4 composite was prepared with Fe-Fe2O3-Al2O3 powder by a hot press sintering method. The mass ratio was 6:1:2, sintering pressure was 30 MPa, and holding time was 120 min. The raw materials for the powder particles were respectively 1 µm (Fe), 0.5 µm (Fe2O3), and 1 µm (Al2O3) in diameter. The effect of sintering temperature on the microstructure and mechanical properties of Fe/FeAl2O4 composite was studied. The results showed that Fe/FeAl2O4 composite was formed by in situ reaction at 1300 °C–1500 °C. With the increased sintering temperature, the microstructure and mechanical properties of the Fe/FeAl2O4 composite showed a change law that initially became better and then became worse. The best microstructure and optimal mechanical properties were obtained at 1400 °C. At this temperature, the grain size of Fe and FeAl2O4 phases in Fe/FeAl2O4 composite was uniform, the relative density was 96.7%, and the Vickers hardness and bending strength were 1.88 GPa and 280.0 MPa, respectively. The wettability between Fe and FeAl2O4 was enhanced with increased sintering temperature. And then the densification process was accelerated. Finally, the microstructure and mechanical properties of the Fe/FeAl2O4 composite were improved.

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