Raman scattering from boron nitride coatings at high temperatures

1991 ◽  
Vol 69 (4) ◽  
pp. 2543-2548 ◽  
Author(s):  
Gregory J. Exarhos ◽  
Joel W. Schaaf
Keyword(s):  
Boron Nitride ◽  
Raman Scattering ◽  
High Temperatures ◽  
Nitride Coatings

Facility for Continuous CVD Coating of Ceramic Fibers

1991 ◽  
Vol 250 ◽  
Author(s):  
Arthur W. Moore
Keyword(s):  
Boron Nitride ◽  
High Temperatures ◽  
Weight Ratio ◽  
High Strength ◽  
Ceramic Coatings ◽  
Ceramic Composites ◽  
Ceramic Fiber ◽  
Ceramic Fibers ◽  
Fiber Properties ◽  
Nitride Coatings

The development of new and improved ceramic fibers has spurred the development and application of ceramic composites with improved strength, strength/weight ratio, toughness, and durability at increasingly high temperatures. For many systems, the ceramic fibers can be used without modification because their properties are adequate for the chosen application. However, in order to take maximum advantage of the fiber properties, it is often necessary to coat the ceramic fibers with materials of different composition and properties. Examples include (1) boron nitride coatings on a ceramic fiber, such as Nicalon silicon carbide, to prevent reaction with the ceramic matrix during fabrication and to enhance fiber pullout and increase toughness when the ceramic composite is subjected to stress[l]; (2) boron nitride coatings on ceramic yarns, such as Nicalon for use as thermal insulation panels in an aerodynamic environment, to reduce abrasion of the Nicalon and to inhibit the oxidation of free carbon contained within the Nicalon[2]; and (3) ceramic coatings on carbon yarns and carbon-carbon composites to permit use of these high-strength, high-temperature materials in oxidizing environments at very high temperatures[3,4].

Screening effect of monolayer van der Waals crystals on surface deicing: a molecular simulation study

2020 ◽  
Vol 22 (47) ◽  
pp. 27873-27881
Author(s):  
Yue Wang ◽  
Yufeng Guo ◽  
Wanlin Guo
Keyword(s):  
Boron Nitride ◽  
Molecular Simulation ◽  
Simulation Study ◽  
Hexagonal Boron Nitride ◽  
Van Der Waals ◽  
Monolayer Graphene ◽  
Screening Effect ◽  
Nitride Coatings

Significant screening effect of monolayer graphene and hexagonal boron nitride coatings on surface deicing of superhydrophilic and superhydrophobic crystals.

Plasma assisted chemical vapour deposition of boron nitride coatings from using BCl3–N2–H2–Ar gas mixture

Vacuum ◽  
1999 ◽  
Vol 52 (1-2) ◽  
pp. 169-181 ◽  
Author(s):  
F. Rossi ◽  
C. Schaffnit ◽  
L. Thomas ◽  
H. del Puppo ◽  
R. Hugon
Keyword(s):  
Boron Nitride ◽  
Chemical Vapour Deposition ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
Gas Mixture ◽  
Nitride Coatings ◽  
Ar Gas

Characterization of Boron Nitride Coated Silicon Carbide Fibers and Composites

1997 ◽  
Vol 3 (S2) ◽  
pp. 733-734
Author(s):  
Mani Gopal
Keyword(s):  
Silicon Carbide ◽  
Boron Nitride ◽  
High Temperatures ◽  
Specimen Preparation ◽  
Ion Milling ◽  
Sic Fibers ◽  
Silicon Carbide Fibers ◽  
Pull Out ◽  
Sic Composites

Silicon carbide (SiC) composites are receiving much attention for structural use at high temperatures. One class of composites are those reinforced with SiC fibers. The SiC fibers are coated with boron nitride (BN) which is weakly bonded to the fiber. During fracture, the coating deflects cracks causing pull-out of the fibers (Fig. 1). This process of fiber pull-out consumes energy and increases the toughness of the composite. Although much work has been done on characterizing these materials by SEM, not much has been done using TEM due to difficulties in specimen preparation. The purpose of this study is to characterize these fibers and composites using conventional and analytical TEM.In this study, TEM specimens were prepared by dimpling and ion milling. Careful control of the preparation was needed to ensure the integrity of the SiC-BN interface. Figure 2a is a TEM image of the fiber showing delamination at the SiC-BN interface.

Boron ink assisted in situ boron nitride coatings for anti-oxidation and anti-corrosion applications

2019 ◽  
Vol 30 (33) ◽  
pp. 335704 ◽  
Author(s):  
Hongbo Jiang ◽  
Zifeng Wang ◽  
Longtao Ma ◽  
Qi Yang ◽  
Zijie Tang ◽  
...  
Keyword(s):  
Boron Nitride ◽  
Nitride Coatings

scholarly journals Vibrational Spectroscopy of Boron Nitride at High Temperatures and Pressures

1989 ◽  
Vol 162 ◽  
Author(s):  
Gregory Y. Exarhos ◽  
Nancy J. Hess
Keyword(s):  
Boron Nitride ◽  
Bulk Material ◽  
Hexagonal Phase ◽  
Bulk Materials ◽  
Lattice Thermal Expansion ◽  
Line Frequency ◽  
Nitride Coatings ◽  
Scattering Measurements ◽  
Sputter Deposited ◽  
Inherent Strain

ABSTRACTRaman scattering measurements are used to distinguish between amorphous and crystalline phases in sputter deposited boron nitride coatings and bulk materials. Changes in vibrational line frequency and linewidth can be attributed to differences in particle size or inherent strain which can be quantified from pressure-dependent measurements of the bulk material. The response of the Raman-allowed E2g modes (hexagonal phase) to temperature is described by a forced dampeg harmonic oscillator model from which the intra- and interplanar lattice thermal expansion can be estimated.

Lubrication at High Temperatures With Vapor-Deposited Surface Coatings

1961 ◽  
Vol 83 (2) ◽  
pp. 133-138 ◽  
Author(s):  
D. J. Baldwin ◽  
G. W. Rowe
Keyword(s):  
Experimental Study ◽  
Stainless Steel ◽  
High Temperature ◽  
Boron Nitride ◽  
High Temperatures ◽  
Indentation Test ◽  
Surface Coatings ◽  
Molybdenum Disulphide ◽  
High Coefficient ◽  
Inorganic Films

An experimental study of the friction of metals which have been coated with inorganic films by reaction with their surrounding atmosphere. The specimens are first cleaned at high temperature in vacuo and then heated in the selected reactive vapor. Many coatings will prevent seizure and give a fairly constant but high coefficient of friction up to high temperatures. Layer-lattice compounds such as MoS2, CrCl3, and TiI2 give much lower friction at all temperatures below those at which the film decomposes or evaporates (about 850 C for molybdenum disulphide). A film of boron nitride formed on boron shows a high intrinsic friction, but this can be reduced by certain vapors or by raising the temperature above about 800 C. Most of the experiments were performed with very light loads but the films are shown to be effective under kilogram loads. A simple indentation test capable of selecting lubricants under loads up to 12 tons is described. This shows that a film formed by heating stainless steel in CCl2F2 will lubricate at 400 C when the steel is deformed by over 50 per cent.

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