Crystalline-amorphous interfaces and their relation to grain boundary films

doi:https://doi.org/10.2172/5738322

Title: Crystalline-amorphous interfaces and their relation to grain boundary films

Full Record
Other Related Research

Abstract

In presence of glass in grain boundaries greatly enhances sintering, in part, because transport of matter along and across the intergranular regions is faster. The glass does not simply act as a catalyst but also changes the character of the interfacial regions. In particular, it tends to encourage faceting of the grains; the scale of this faceting may vary from nanometers to microns. After processing, the glass may remain as a thin layer in the interface during preparation of the polycrystalline compact as was initially demonstrated for Si{sub 3}N{sub 4} and proposed for other ceramics. The glass may also crystallize to form an intergranular crystalline layer or it may withdraw from the planar interfaces into three-grain and four-grain junctions (the dewetting process). The present program has begun to examine how glass affects and interacts with crystalline ceramics. The main aim of the program is to examine how glass moves into and out of grain boundaries and why this movement takes. By understanding this process we will be better able to control this important aspect of many ceramic materials. Since TEM is the main tool used in this investigation, we will continue to develop methods for analyzing interfaces as part ofmore » this program.« less

Authors:

Carter, C B ^[1]

Minnesota Univ., Minneapolis, MN (United States). Dept. of Chemical Engineering and Materials Science

Publication Date:: 1992-02-03

Research Org.:: Cornell Univ., Ithaca, NY (United States). Dept. of Materials Science and Engineering

Sponsoring Org.:: USDOE; USDOE, Washington, DC (United States)

OSTI Identifier:: 5738322

Report Number(s):: DOE/ER/45381-3
ON: DE92009812

DOE Contract Number:: FG02-89ER45381

Resource Type:: Technical Report

Country of Publication:: United States

Language:: English

Subject:: 36 MATERIALS SCIENCE; CERAMICS; INTERFACES; SINTERING; GLASS; ALUMINIUM OXIDES; AMORPHOUS STATE; GRAIN BOUNDARIES; PROGRESS REPORT; SILICON NITRIDES; ALUMINIUM COMPOUNDS; CHALCOGENIDES; CRYSTAL STRUCTURE; DOCUMENT TYPES; FABRICATION; MICROSTRUCTURE; NITRIDES; NITROGEN COMPOUNDS; OXIDES; OXYGEN COMPOUNDS; PNICTIDES; SILICON COMPOUNDS; 360201* - Ceramics, Cermets, & Refractories- Preparation & Fabrication; 360202 - Ceramics, Cermets, & Refractories- Structure & Phase Studies; 360602 - Other Materials- Structure & Phase Studies

Citation Formats


                    Carter, C B. Crystalline-amorphous interfaces and their relation to grain boundary films.  United States: N. p., 1992. 
        Web.  doi:10.2172/5738322.

Copy to clipboard


                    Carter, C B. Crystalline-amorphous interfaces and their relation to grain boundary films.  United States.  https://doi.org/10.2172/5738322

Copy to clipboard


                    Carter, C B. Mon .  
        "Crystalline-amorphous interfaces and their relation to grain boundary films".  United States.  https://doi.org/10.2172/5738322.  https://www.osti.gov/servlets/purl/5738322.

Copy to clipboard


                    
@article{osti_5738322,

  title        = {Crystalline-amorphous interfaces and their relation to grain boundary films},

  author       = {Carter, C B},

  abstractNote = {In presence of glass in grain boundaries greatly enhances sintering, in part, because transport of matter along and across the intergranular regions is faster. The glass does not simply act as a catalyst but also changes the character of the interfacial regions. In particular, it tends to encourage faceting of the grains; the scale of this faceting may vary from nanometers to microns. After processing, the glass may remain as a thin layer in the interface during preparation of the polycrystalline compact as was initially demonstrated for Si{sub 3}N{sub 4} and proposed for other ceramics. The glass may also crystallize to form an intergranular crystalline layer or it may withdraw from the planar interfaces into three-grain and four-grain junctions (the dewetting process). The present program has begun to examine how glass affects and interacts with crystalline ceramics. The main aim of the program is to examine how glass moves into and out of grain boundaries and why this movement takes. By understanding this process we will be better able to control this important aspect of many ceramic materials. Since TEM is the main tool used in this investigation, we will continue to develop methods for analyzing interfaces as part of this program.},

  doi          = {10.2172/5738322},

  url          = {https://www.osti.gov/biblio/5738322},
  journal      = {},
number       = ,

  volume       = ,

  place        = {United States},

  year         = {1992},

  month        = {2}

}

Copy to clipboard

Technical Report:

View Technical Report (1.12 MB)

https://doi.org/10.2172/5738322

Save / Share:

Export Metadata

Save to My Library

Similar records in OSTI.GOV collections:

Crystalline-amorphous interfaces and their relation to grain boundary films. A report for the 3-year period, 15 November 1988--14 November 1991

Technical Report Carter, C B

In presence of glass in grain boundaries greatly enhances sintering, in part, because transport of matter along and across the intergranular regions is faster. The glass does not simply act as a catalyst but also changes the character of the interfacial regions. In particular, it tends to encourage faceting of the grains; the scale of this faceting may vary from nanometers to microns. After processing, the glass may remain as a thin layer in the interface during preparation of the polycrystalline compact as was initially demonstrated for Si{sub 3}N{sub 4} and proposed for other ceramics. The glass may also crystallizemore »« less
https://doi.org/10.2172/10131126

Full Text Available
SiAlON COATINGS OF SILICON NITRIDE AND SILICON CARBIDE

Technical Report Nowok, Jan W ; Hurley, John P ; Kay, John P

The need for new engineering materials in aerospace applications and in stationary power turbine blades for high-efficiency energy-generating equipment has led to a rapid development of ceramic coatings. They can be tailored to have superior physical (high specific strength and stiffness, enhanced high-temperature performance) and chemical (high-temperature corrosion resistance in more aggressive fuel environments) properties than those of monolithic ceramic materials. Among the major chemical properties of SiAlON-Y ceramics are their good corrosion resistance against aggressive media combined with good thermal shock behavior. The good corrosion resistance results from the yttria-alumina-garnet (YAG), Al{sub 5}Y{sub 3}O{sub 12}, formed during the corrosionmore »« less
https://doi.org/10.2172/824976

Full Text Available
A model for viscous flow creep in ceramics containing secondary crystalline phases

Journal Article Jin, Q ; Wilkinson, D S ; Weatherly, G C - Scripta Materialia

Many structural ceramics (e.g., Si{sub 3}N{sub 4}) contain an intergranular amorphous phase which results from liquid phase sintering. This amorphous phase is present both at the multigrain junctions and as thin films at two-grain boundaries. High temperature creep deformation of these materials may occur by viscous flow of the amorphous phase from grain boundaries in compression to those in tension. Several models have been developed to describe this process, based on the assumption of either square or hexagonal grains. All these models assumed that the grain size and grain boundary film thickness were uniform throughout the material. In polycrystalline material,more »« less
https://doi.org/10.1016/S1359-6462(99)00263-8
Chemical bonding of oxygen in intergranular amorphous layers in high-purity {beta}-SiC ceramics

Journal Article Kaneko, K ; Yoshiya, M ; Tanaka, I ; ... - Acta Materialia

An amorphous intergranular layer, 0.4 nm thick, is found by high-resolution transmission electron microscopy of {beta}-SiC ceramics fabricated by the HIP glass-encapsulation technique without the use of additives. The intergranular layer is found to contain oxygen, which may also be present in the SiC grains near the grain boundary. The mean composition of the intergranular layer is determined to be SiO{sub 010{+-}0.01}C{sub 0.93{+-}0.04}, whose C/O ratio is close to a hypothetical Si-oxycarbide stoichiometry. Electron energy loss spectroscopy shows that both the Si-L{sub 23} and O-K edges from the intergranular layer are distinctive compared to those of SiC and/or SiO{sub 2}.more »« less
https://doi.org/10.1016/S1359-6454(98)00423-6
The migration of grain boundaries in ceramic materials with particular reference to the sintering process: A progress report for the period covering approximately November 15, 1987-November 14, 1987

Technical Report Carter, C B

Purpose is to understand how the structure and chemistry of grain boundaries influence the sintering and densification of polycrystalline ceramic materials. The study has been limited to alumina, spinel and germanium. This choice of materials allows effects associated with a particular type of crystal structure of interatomic bonding may be distinguished from effects which are common to all ceramic materials. The following lines of work have been followed: The analysis of surfaces of alumina has been extended to other materials. The faceting of alumina/glass interfaces has been continued. The first alumina bicrystals have been prepared using the new Centaur (2000/supmore »« less

Similar Records