Journal ArticleDOI
Composition and chemical width of ultrathin amorphous films at grain boundaries in silicon nitride
TLDR
In this paper, two different electron energy loss spectroscopy (EELS) quantitative analytical methods for obtaining complete compositions from interface regions are applied to ultrathin oxide-based amorphous grain boundary (GB) films of ∼ 1 nm thickness in high-purity HIPed Si3N4 ceramics.Abstract:
Two different electron energy loss spectroscopy (EELS) quantitative analytical methods for obtaining complete compositions from interface regions are applied to ultrathin oxide-based amorphous grain boundary (GB) films of ∼ 1 nm thickness in high-purity HIPed Si3N4 ceramics. The first method, 1, is a quantification of the segregation excess at interfaces for all the elements, including the bulk constituents such as silicon and nitrogen; this yields a GB film composition of SiN0.49±1.4O1.02±0.42 when combined with the average film thickness from high resolution electron microscopy (HREM). The second method, II, is based on an EELS near-edge structure (ELNES) analysis of the Si–L
2,3 edge of thin GB films which permits a subtraction procedure that yields a completeEELS spectrum, e.g., that also includes the O–K and N–K edges, explicitly for the GB film. From analysis of these spectra, the film composition is directly obtained as SiN0.63±0.19O1.44±0.33, close to the one obtained by the first method but with much better statistical quality. The improved quality results from the fewer assumptions made in method II; while in method I uniform thickness and illumination condition have to beassumed, and correction of such effects yields an extra systematic error. Method II is convenient as it does not depend on the film thickness detected by HREM, nor suffer from material lost by preferential thinning at the GB. In addition, a chemical width for these films can be deduced as 1.33 ± 0.25 nm, that depends on an estimation of film density based on its composition. Such a chemical width is in good agreement with the structural thickness determined by HREM, with a small difference that is probably due to the different way in which these techniques probe the GB film. The GB film compositions are both nonstoichiometric, but in an opposite sense, this discrepancy is probably due to different ways of treating the surface oxidation layers in both methods.read more
Citations
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Journal ArticleDOI
Grain Boundary Complexions
TL;DR: Grain boundary complexion transitions are the root cause of a wide variety of materials phenomena such as abnormal grain growth, grain boundary embrittlement and activated sintering as discussed by the authors, which have defied mechanistic explanation for years.
Journal ArticleDOI
Complexion: A new concept for kinetic engineering in materials science
TL;DR: In this paper, the existence of multiple interface complexions in a real-world material system has been proven by thermodynamics, and it has been shown that an interface complexion can be considered as a separate phase which can be made to transform into different phases with vastly different properties by chemistry and heat treatment.
Journal ArticleDOI
Origins and Applications of London Dispersion Forces and Hamaker Constants in Ceramics
Roger H. French,Roger H. French +1 more
TL;DR: In this paper, the authors used spectral or parametric optical properties of materials, combined with knowledge of the configuration of the materials, to determine the long-range van der Waals forces.
Journal ArticleDOI
Diffuse interface model for structural transitions of grain boundaries
TL;DR: In this paper, the conditions for structural transitions at the core of a grain boundary separating two crystals were investigated with a diffuse interface model that incorporates disorder and crystal orientation, and the model predicts that limited structural disorder near the grain boundary core can be favorable below the melting point.
Journal ArticleDOI
Interface structure and atomic bonding characteristics in silicon nitride ceramics.
A. Ziegler,A. Ziegler,Juan Carlos Idrobo,Michael K. Cinibulk,Christian Kisielowski,Nigel D. Browning,Nigel D. Browning,Robert O. Ritchie,Robert O. Ritchie +8 more
TL;DR: Direct atomic resolution images have been obtained that illustrate how a range of rare-earth atoms bond to the interface between the intergranular phase and the matrix grains in an advanced silicon nitride ceramic to critically improve the materials' performance in wide-ranging applications.
References
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Creep in polycrystalline aggregates by matter transport through a liquid phase
TL;DR: In this paper, the authors derived constitutive equations for creep rate and densification rate of polycrystalline aggregates and showed that the rate may be controlled either by the interface kinetics of dissolution/precipitation of the crystal from the liquid or by the diffusion rate of matter through the liquid.
Journal ArticleDOI
Statistical analysis of the intergranular film thickness in silicon nitride ceramics
TL;DR: In this paper, the authors used high-resolution electron microscopy (HREM) to study grain-boundary intergranular films in different Si[sub 3]N[sub 4] ceramics.
Journal ArticleDOI
On the detection of thin intergranular films by electron microscopy
TL;DR: The presence of very thin (6-50 A) films in integrated circuits and separating crystalline grains in ceramics, notably in zinc oxide varistors and in silicon nitride, has been reported using high resolution electron microscopy as mentioned in this paper.
BookDOI
Tailoring of mechanical properties of Si[3]N[4] ceramics
TL;DR: This paper presents a meta-analysis of grain Boundary Phases of Silicon Nitride Ceramics using SiA1ON Composites, a porous material derived from Oxynitride, which has shown the ability to retain its oxide-like properties at high temperatures.
Journal ArticleDOI
Calcium Concentration Dependence of the Intergranular Film Thickness in Silicon Nitride
Isao Tanaka,Isao Tanaka,Hans-Joachim Kleebe,Hans-Joachim Kleebe,Michael K. Cinibulk,Michael K. Cinibulk,John Bruley,John Bruley,David R. Clarke,David R. Clarke,Manfred Rühle,Manfred Rühle +11 more
TL;DR: In this paper, high-resolution electron microscopy and nano-beam analytical electron microscope were used to characterize both the intergranular silicate film thickness and its local composition in a series of high-purity Si3N4 ceramics doped with 0.450 at. ppm Ca.