Preparation of a ZrO2–Al2O3 nanocomposite by high-pressure sintering of spray-pyrolyzed powders

ZrO2–Al2O3 powders were synthesized by spray pyrolysis. These powders were sintered at 1 GPa in the temperature range of 700–1100 °C. The microstructural evolution and densification are reported in this paper. The application of 1 Gpa pressure lowers the crystallization temperature from ∼850 to <700 °C. Similarly, the transformation temperature under 1 GPa pressure for γ → α–Al2O3 reduces from ∼1100 to 700–800 °C range, and that for t → m ZrO2 reduces from ∼1050 to 700–800 °C range. It was possible to obtain highly dense nanocrystalline ZrO2–Al2O3 composite at temperatures as low as 700 °C. The effect of high pressure on nucleation and transformation of phases is discussed.

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High pressure sintering of TiB2 ceramics at different temperatures

Processing and Application of Ceramics ◽

10.2298/pac0801009k ◽

2008 ◽

Vol 2 (1) ◽

pp. 9-12 ◽

Cited By ~ 1

Author(s):

Andrei Kapylou ◽

Vladimir Urbanovich ◽

Vladimir Kukareko

Keyword(s):

High Pressure ◽

Average Particle Size ◽

Physical And Mechanical Properties ◽

Xrd Analysis ◽

Internal Stresses ◽

Average Particle ◽

Temperature Range ◽

Fine Grained ◽

High Pressure Sintering ◽

Fine Grained Structure

In this paper the effect of high-pressure sintering (HPS) temperature on the microstructure, physical and mechanical properties of TiB2 ceramics has been investigated. Initial TiB2 powder with the average particle size of 5 ?m was sintered in a modified high-pressure anvil-type apparatus under static pressure of 4 GPa in the temperature range of 1400-1800?C. It is shown that HPS allows preparing full-dense TiB2 ceramics with fine-grained structure. The density of samples rises with increasing the sintering temperature up to 1800?C while the maximal microhardness is observed on samples prepared in the temperature range of 1500-1600?C. XRD analysis has shown that this fact is connected with an increase of the level of internal stresses in these samples.

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Microstructural Study of Diamond Deformed Under High Pressure and Temperature

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100118072 ◽

1985 ◽

Vol 43 ◽

pp. 230-231

Author(s):

E. F. Koch

Keyword(s):

High Pressure ◽

High Temperature ◽

Lattice Structure ◽

Diamond Particle ◽

Polycrystalline Diamond ◽

Sintering Process ◽

Ion Milling ◽

Sintered Compact ◽

Transmission Electron ◽

High Pressure Sintering

Because of the extremely rigid lattice structure of diamond, generating new dislocations or moving existing dislocations in diamond by applying mechanical stress at ambient temperature is very difficult. Analysis of portions of diamonds deformed under bending stress at elevated temperature has shown that diamond deforms plastically under suitable conditions and that its primary slip systems are on the ﹛111﹜ planes. Plastic deformation in diamond is more commonly observed during the high temperature - high pressure sintering process used to make diamond compacts. The pressure and temperature conditions in the sintering presses are sufficiently high that many diamond grains in the sintered compact show deformed microtructures.In this report commercially available polycrystalline diamond discs for rock cutting applications were analyzed to study the deformation substructures in the diamond grains using transmission electron microscopy. An individual diamond particle can be plastically deformed in a high pressure apparatus at high temperature, but it is nearly impossible to prepare such a particle for TEM observation, since any medium in which the diamond is mounted wears away faster than the diamond during ion milling and the diamond is lost.

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The reaction of amorphous Ni-Nb films with Si in the presence of a native SiO2 layer

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100176459 ◽

1990 ◽

Vol 48 (4) ◽

pp. 664-665

Author(s):

N. Rozhanski ◽

A. Barg

Keyword(s):

High Temperature ◽

Crystallization Temperature ◽

Diffusion Barriers ◽

Sio2 Layer ◽

Si Substrate ◽

Cross Sectional ◽

Plan View ◽

Temperature Range ◽

Sputter Deposited

Amorphous Ni-Nb alloys are of potential interest as diffusion barriers for high temperature metallization for VLSI. In the present work amorphous Ni-Nb films were sputter deposited on Si(100) and their interaction with a substrate was studied in the temperature range (200-700)°C. The crystallization of films was observed on the plan-view specimens heated in-situ in Philips-400ST microscope. Cross-sectional objects were prepared to study the structure of interfaces.The crystallization temperature of Ni5 0 Ni5 0 and Ni8 0 Nb2 0 films was found to be equal to 675°C and 525°C correspondingly. The crystallization of Ni5 0 Ni5 0 films is followed by the formation of Ni6Nb7 and Ni3Nb nucleus. Ni8 0Nb2 0 films crystallise with the formation of Ni and Ni3Nb crystals. No interaction of both films with Si substrate was observed on plan-view specimens up to 700°C, that is due to the barrier action of the native SiO2 layer.

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The effect of cooling rate on crystallization behavior and tensile properties of CF/PEEK composites

Journal of Polymer Engineering ◽

10.1515/polyeng-2020-0356 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Guangming Dai ◽

Lihua Zhan ◽

Chenglong Guan ◽

Minghui Huang

Keyword(s):

Cooling Rate ◽

Crystallization Temperature ◽

Crystallization Behavior ◽

Crystalline Polymer ◽

Scanning Calorimetry ◽

Nonisothermal Crystallization ◽

Cooling Rates ◽

Control Range ◽

Temperature Range ◽

Transverse Tensile

Abstract In this study, the differential scanning calorimetry (DSC) tests were performed to measure the nonisothermal crystallization behavior of carbon fiber reinforced polyether ether ketone (CF/PEEK) composites under different cooling rates. The characteristic parameters of crystallization were obtained, and the nonisothermal crystallization model was established. The crystallization temperature range of the material at different cooling rates was predicted by the model. The unidirectional laminates were fabricated at different cooling rates in the crystallization temperature range. The results showed that the crystallization temperature range shifted to a lower temperature with the increase of cooling rate, the established nonisothermal crystallization model was consistent with the DSC test results. It is feasible to shorten the cooling control range from the whole process to the crystallization range. The crystallinity and transverse tensile strength declined significantly with the increase of the cooling rate in the crystallization temperature range. The research results provided theoretical support for the selection of cooling conditions and temperature control range, which could be applied to the thermoforming process of semi-crystalline polymer matrixed composites to improve the manufacturing efficiency.

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Optimized substrate temperature range for improved physical properties in spray pyrolysis deposited Tin Selenide thin films

Materials Chemistry and Physics ◽

10.1016/j.matchemphys.2016.02.078 ◽

2016 ◽

Vol 175 ◽

pp. 118-124 ◽

Cited By ~ 3

Author(s):

Sharmistha Anwar ◽

B.K. Mishra ◽

Shahid Anwar

Keyword(s):

Thin Films ◽

Substrate Temperature ◽

Physical Properties ◽

Spray Pyrolysis ◽

Temperature Range ◽

Tin Selenide

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Foam glass obtained through high‐pressure sintering

Journal of the American Ceramic Society ◽

10.1111/jace.15574 ◽

2018 ◽

Vol 101 (9) ◽

pp. 3917-3923 ◽

Cited By ~ 10

Author(s):

Martin B. Østergaard ◽

Rasmus R. Petersen ◽

Jakob König ◽

Michal Bockowski ◽

Yuanzheng Yue

Keyword(s):

High Pressure ◽

Foam Glass ◽

High Pressure Sintering

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Enhanced crystallization and phase transformation of amorphous silicon nitride under high pressure

Journal of Materials Research ◽

10.1557/jmr.2001.0014 ◽

2001 ◽

Vol 16 (1) ◽

pp. 67-75 ◽

Cited By ~ 3

Author(s):

Ya-Li Li ◽

Yong Liang ◽

Fen Zheng ◽

Xian-Feng Ma ◽

Suo-Jing Cui ◽

...

Keyword(s):

High Pressure ◽

Phase Transformation ◽

Silicon Nitride ◽

Amorphous Silicon ◽

Crystallization Temperature ◽

Amorphous Materials ◽

Normal Pressure ◽

Nucleation And Growth ◽

Amorphous Silicon Nitride ◽

Amorphous Si

The crystallization and phase transformation of amorphous Si3N4 ceramics under high pressure (1.0–5.0 GPa) between 800 and 1700 °C were investigated. A greatly enhanced crystallization and α–β transformation of the amorphous Si3N4 ceramics were evident under the high pressure, as characterized by that, at 5.0 GPa, the amorphous Si3N4 began to crystallize at a temperature as low as 1000 °C (to transform to a modification). The subsequent a–b transformation occurred completed between 1350 and 1420 °C after only 20 min of pressing at 5.0 GPa. In contrast, under 0.1 MPa N2, the identical amorphous materials were stable up to 1400 °C without detectable crystallization, and only a small amount of a phase was detected at 1500 °C. The crystallization temperature and the a–b transformation temperatures are reduced by 200–350 °C compared to that at normal pressure. The enhanced phase transformations of the amorphous Si3N4 were discussed on the basis of thermodynamic and kinetic consideration of the effects of pressure on nucleation and growth.

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