Sintering of Si3N4 Ceramics in Air Atmosphere Furnace(Part 2)-Agglomeration of Packing Powder and Deterioration of Al2O3 Crucible-

Si2N2O matrix composites were fabricated by solid/gas reaction in air or N2 atmosphere. The effects of atmosphere on the phase and microstructure of the composites were investigated. The reaction mechanism of Si2N2O system was discussed by analysing the variation of the Gibbs free energy with temperature. The effect of N2 and air on sintering of Si2N2O matrix composites was discussed in relation to observed kinetics and thermodynamic calculations. The results showed that gradient structure of Si2N2O matrix composites were obtained in N2 atmosphere. While high N2 concentration was useful for the formation of the pure ?-Si3N4 ceramics, low N2 concentration was proposed to form the pure Si2N2O ceramics. However, in the air atmosphere, structure of the Si3N4/SiO2 composites is homogeneous without the gradient structure appearing. Its composition is a little different as the O2 concentration changes.

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Wettability and interfacial reaction mechanism between Ag–Cu alloy and Si3N4 ceramics in air atmosphere

Ceramics International ◽

10.1016/j.ceramint.2021.08.209 ◽

2021 ◽

Author(s):

Ruidong Wang ◽

Chao Zhang ◽

Dan Li ◽

Zixin Xie ◽

Yuwen Zhang ◽

...

Keyword(s):

Reaction Mechanism ◽

Interfacial Reaction ◽

Air Atmosphere ◽

Cu Alloy ◽

Si3n4 Ceramics

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HREM interface studies in SiC-whisker-reinforced Al2O3 and Si3N4 ceramics

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100105734 ◽

1988 ◽

Vol 46 ◽

pp. 734-735

Author(s):

W. Braue ◽

R.W. Carpenter ◽

D.J. Smith

Keyword(s):

Analytical Data ◽

Base Material ◽

High Strength ◽

Ceramic Composites ◽

Good Thermal Stability ◽

All Ceramic ◽

Sic Whiskers ◽

Base Composite ◽

C 30 ◽

Si3n4 Ceramics

Whisker and fiber reinforcement has been established as an effective toughening concept for monolithic structural ceramics to overcome limited fracture toughness and brittleness. SiC whiskers in particular combine both high strength and elastic moduli with good thermal stability and are compatible with most oxide and nonoxide matrices. As the major toughening mechanisms - crack branching, deflection and bridging - in SiC whiskenreinforced Al2O3 and Si3N41 are critically dependent on interface properties, a detailed TEM investigation was conducted on whisker/matrix interfaces in these all-ceramic- composites.In this study we present HREM images obtained at 400 kV from β-SiC/α-Al2O3 and β-SiC/β-Si3N4 interfaces, as well as preliminary analytical data. The Al2O3- base composite was hotpressed at 1830 °C/60 MPa in vacuum and the Si3N4-base material at 1725 °C/30 MPa in argon atmosphere, respectively, adding a total of 6 vt.% (Y2O3 + Al2O3) to the latter to promote densification.

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ON THE MECHANISMS OF POROUS SILICON COMBUSTION IN OXYGEN AND AIR ATMOSPHERE WHEN SODIUM PERCHLORATE IS INCORPORATED IN PORES

NONEQUILIBRIUM PROCESSES. Vol. 2. Fundamentals of combustion ◽

10.30826/nepcap2018-2-13 ◽

2020 ◽

Author(s):

V. N. MIRONOV ◽

◽

O. G. PENYAZKOV ◽

P. N. KRIVOSHEYEV ◽

I. A. IVANOV ◽

...

Keyword(s):

Porous Silicon ◽

Porous Layer ◽

Sodium Perchlorate ◽

Spark Ignition ◽

Joule Heat ◽

Air Atmosphere ◽

Breakdown Region ◽

Ignition And Combustion ◽

Heating Up

The processes of pSi ignition and combustion in oxygen are described. When spark ignition in the porous layer releases the Joule heat, it leads to a significant heating-up of the breakdown region.

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