Influence of oxidation on the composition and structure of the surface layer of hot-pressed boron carbide
The oxidation of hot-pressed boron carbide under isothermal conditions and under conditions of programmed heating up to 1500/degrees/C was investigated. Oxidized samples were studied by secondary-ion mass spectrometry, X-ray photoelectron spectroscopy, scanning electron microscopy, energy-dispersive X-ray microanalysis, X-ray diffraction, and other methods. It has been demonstrated that oxidation starts above 600/degrees/C and results in the formation of a thin transparent B/sub 2/O/sub 3/ film that is cracked after cooling. Up to 1200/degrees/C, the oxidation process is limited by the diffusion of reagents through the oxide layer; at higher temperatures, it is determined by the rate of chemical reaction of carbide with oxygen in the air. During boron carbide oxidation the etching of grain boundaries occurs, it results in strength degradation at higher temperatures.
- Research Organization:
- Institute for Problems of Materials Science, Kiev (USSR)
- OSTI ID:
- 5928467
- Journal Information:
- Oxid. Met.; (United States), Vol. 29:3-4
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
BORON CARBIDES
OXIDATION
BORON OXIDES
MECHANICAL PROPERTIES
CERAMICS
CHEMICAL REACTION KINETICS
ETCHING
GRAIN BOUNDARIES
ION MICROPROBE ANALYSIS
MASS SPECTROSCOPY
PHOTOELECTRON SPECTROSCOPY
SCANNING ELECTRON MICROSCOPY
STRESS INTENSITY FACTORS
X-RAY DIFFRACTION
X-RAY SPECTROSCOPY
BORON COMPOUNDS
CARBIDES
CARBON COMPOUNDS
CHALCOGENIDES
CHEMICAL ANALYSIS
CHEMICAL REACTIONS
COHERENT SCATTERING
CRYSTAL STRUCTURE
DIFFRACTION
ELECTRON MICROSCOPY
ELECTRON SPECTROSCOPY
KINETICS
MICROANALYSIS
MICROSCOPY
MICROSTRUCTURE
NONDESTRUCTIVE ANALYSIS
OXIDES
OXYGEN COMPOUNDS
REACTION KINETICS
SCATTERING
SPECTROSCOPY
SURFACE FINISHING
360205* - Ceramics
Cermets
& Refractories- Corrosion & Erosion
360202 - Ceramics
Cermets
& Refractories- Structure & Phase Studies
360203 - Ceramics
Cermets
& Refractories- Mechanical Properties