Ceramic Coatings Obtained on Superalloys Modified by Laser Treatment

1998 ◽  
Author(s):  
K. Kobylanska-Szkaradek ◽  
L. Swadzba
Keyword(s):  
High Temperature ◽  
Chemical Composition ◽  
Laser Beam ◽  
Ceramic Coatings ◽  
Thermal Barrier ◽  
Laser Remelting ◽  
Scanning Rate ◽  
The Matrix ◽  
Laser Beam Scanning

Abstract The paper presents the influence of laser-beam remelting of Al203-Ni ceramic layers spread on creep-resisting alloy by means of plasma spray upon the quality of ceramic coatings, which form thermal barrier and high temperature corrosion shield of these alloys. The examination showed that 0.103.109 W/m2 power density laser-beam scanning ensures good quality of coatings at beam moving rate 1 to 2 m/min. At smaller scanning rate, laser remelted ceramic layer spalls and chips. Better quality of the ceramic coatings can be obtained by diffusive chromoaluminizing applied prior to laser remelting. Laser-beam remelting conditions of such layers, elaborated in the course of examination, ensure pores fading, decrease of remelted layer thickness and increase of base adhesion without cracks, chips and spalls. Additionally remelted zone features either strong break up of structure or the structure is amorphic with unchanged chemical composition as to the matrix chemical composition. Obtained results are the base for the elaboration of thermal barrier technology and the technology of anticorrosion shield for creep - resisting alloys applied in high temperature power engineering.

Thermal Barrier Effects Comparison of Plasma-Sprayed and Laser-Remelted Al2O3-13 % TiO2 Ceramic Coatings

2014 ◽  
Vol 978 ◽  
pp. 40-43
Author(s):  
Dong Sheng Wang ◽  
Guang Qu ◽  
Jin Lan Su
Keyword(s):  
Ceramic Coating ◽  
Ceramic Coatings ◽  
Nanostructured Coating ◽  
Thermal Barrier ◽  
Heat Current ◽  
Barrier Effect ◽  
Laser Remelting ◽  
Plasma Sprayed ◽  
Sprayed Coatings ◽  
Conventional Coating

Conventional and nanosturctured Al2O3–13 wt% TiO2ceramic coatings were deposited by plasma spraying on TiAl alloy surface. Laser remelting experiment on as-sprayed coatings was carried out and the influences of laser remelting on microstructure and thermal barrier effect of the coating were researched. The results show that the as-sprayed conventional coating has a typical plasma-sprayed lamellar-like structure, while the nanostructured coating consisted of both fully melted regions and partially melted regions. The laser-remelted conventional coating exhibits column-like crystals which grew along the direction of the heat current, while the nanostructured coating composed of fine equiaxed grains with some remained nanoparticles. The nanostructured ceramic coating has higher thermal barrier effect than the conventional ceramic coating does. The thermal barrier effect of the as-sprayed coatings decreases after laser remelting.

High Temperature Oxidation Behavior of NiAl and Ni3Al Argon Arc Claddings

2011 ◽  
Vol 189-193 ◽  
pp. 441-446
Author(s):  
Xiao Xia Tan ◽  
Zong De Liu
Keyword(s):  
High Temperature ◽  
High Temperature Oxidation ◽  
Steel Substrate ◽  
Temperature Oxidation ◽  
Metallurgical Bonding ◽  
The Matrix ◽  
Oxidation Properties ◽  
High Temperature Oxidation Behavior ◽  
16Mn Steel

NiAl and Ni3Al intermetallic compound claddings are prepared by argon arc cladding technology on the 16Mn steel substrate. These claddings were oxidized for 100 hours at 850 and the oxide quality of each sample was recorded every 10 hours. The results show that the NiAl and Ni3Al claddings have homogeneous structure and few defects, and form excellent metallurgical bonding with the matrix. The oxidation kinetics results show that, the oxidation weight gain rate of NiAl was more stable than Ni3Al and tended to zero earlier. Oxide layer spallation of Ni3Al cladding was more serious than that of NiAl cladding. Thus, NiAl argon arc cladding has the more excellent high temperature oxidation properties than Ni3Al argon arc cladding.

scholarly journals Porcelain Enamel Coatings

Encyclopedia ◽  
2021 ◽  
Vol 1 (2) ◽  
pp. 388-400
Author(s):  
Francesca Russo ◽  
Stefano Rossi ◽  
Attilio Monzio Compagnoni
Keyword(s):  
High Temperature ◽  
Chemical Bond ◽  
Firing Temperature ◽  
Glass Structure ◽  
Ceramic Coatings ◽  
Glass Mass ◽  
Temperature Firing ◽  
The Matrix

Porcelain enamel is an inorganic-type coating, which is applied to metals or glass for both decorative and functional purposes. This coating is a silica-based solidified glass mass obtained by high-temperature firing (temperature can range between 450 and 1200 °C depending on the substrate). Porcelain enamel coatings differ from ceramic coatings mainly by their glass structure and dilatation coefficient, and from organic paints mainly by the inorganic nature of the matrix and the chemical bond that exists between the coating and the substrate.

The Study of High Temperature Oxidation Performance of Thermal Barrier Coatings Prepared by Plasma Spraying and Laser Remelting

2017 ◽  
Vol 1142 ◽  
pp. 161-167
Author(s):  
Yin Qun Hua ◽  
Wen Wen Shuai ◽  
Wei Liu ◽  
Rui Fang Chen ◽  
Jiang Dong Cao
Keyword(s):  
Phase Transformation ◽  
High Temperature ◽  
Plasma Spraying ◽  
High Temperature Oxidation ◽  
Thermal Barrier ◽  
Laser Remelting ◽  
Temperature Oxidation ◽  
Barrier Coating ◽  
Phase Size ◽  
T Phase

The CoCrAlYTaSi/YSZ thermal barrier coating was prepared on the surface of GH586 by plasma spraying and laser remelting process. The coating prepared by plasma spraying, YSZ have no phase transformation. After remelting, YSZ also have no phase transformation, but the grain of the preferential growth orientation changed. Plasma spraying coating is mainly composed of t and t' phase, all the t phase transform into t' phase and recrystallization after remelting. After remelting, the substrate grain and γ' phase size are obviously grown up, leading to the decrease of high temperature oxidation resistance of substrate. In the process of oxidation, no obvious phase transformation are taken place in the plasma spraying coating, and the coating after laser remelting, tetragonal-monoclinic phase transformation happened.

Characterization of thermal barrier coatings formed by electon-beam physical vapor deposition (EB-PVD)

1989 ◽  
Vol 47 ◽  
pp. 426-427
Author(s):  
Ozer Unal
Keyword(s):  
Thermal Barrier Coatings ◽  
Physical Vapor Deposition ◽  
Ceramic Coating ◽  
High Vacuum ◽  
Ceramic Coatings ◽  
High Energy ◽  
Thermal Barrier ◽  
Protective Oxide ◽  
Barrier Coatings ◽  
Energy Beam

Interest in ceramics as thermal barrier coatings for hot components of turbine engines has increased rapidly over the last decade. The primary reason for this is the significant reduction in heat load and increased chemical inertness against corrosive species with the ceramic coating materials. Among other candidates, partially-stabilized zirconia is the focus of attention mainly because ot its low thermal conductivity and high thermal expansion coefficient.The coatings were made by Garrett Turbine Engine Company. Ni-base super-alloy was used as the substrate and later a bond-coating with high Al activity was formed over it. The ceramic coatings, with a thickness of about 50 μm, were formed by EB-PVD in a high-vacuum chamber by heating the target material (ZrO2-20 w/0 Y2O3) above its evaporation temperaturef >3500 °C) with a high-energy beam and condensing the resulting vapor onto a rotating heated substrate. A heat treatment in an oxidizing environment was performed later on to form a protective oxide layer to improve the adhesion between the ceramic coating and substrate. Bulk samples were studied by utilizing a Scintag diffractometer and a JEOL JXA-840 SEM; examinations of cross-sectional thin-films of the interface region were performed in a Philips CM 30 TEM operating at 300 kV and for chemical analysis a KEVEX X-ray spectrometer (EDS) was used.

Structural/Property Relationships for Optical Materials

1993 ◽  
Vol 329 ◽  
Author(s):  
Vivien D.
Keyword(s):  
Crystal Structure ◽  
Optical Properties ◽  
Electronic Structure ◽  
Chemical Composition ◽  
Field Strength ◽  
Optical Materials ◽  
Site Occupancy ◽  
Laser Materials ◽  
Crystal Field Strength ◽  
The Matrix

AbstractIn this paper the relationships between the crystal structure, chemical composition and electronic structure of laser materials, and their optical properties are discussed. A brief description is given of the different laser activators and of the influence of the matrix on laser characteristics in terms of crystal field strength, symmetry, covalency and phonon frequencies. The last part of the paper lays emphasis on the means to optimize the matrix-activator properties such as control of the oxidation state and site occupancy of the activator and influence of its concentration.

INFLUENCE OF FORCED CONVECTION IN LIQUID INSIDE THE TIN ON DURATION OF STERILIZATION IN THE COURSE OF FISH PROCESSING

2017 ◽  
pp. 137-144
Author(s):  
Gennadiy Valentinovich Alexeev ◽  
Elena Igorevna Verboloz
Keyword(s):  
High Temperature ◽  
Liquid Phase ◽  
Forced Convection ◽  
Thermal Process ◽  
Processing Time ◽  
Fish Processing ◽  
Study Results ◽  
Equipment Modernization ◽  
Bottom To Top

The article focuses on the process of intensive mixing of liquid phase in the tin during high-temperature sterilization, i.e. sterilization when temperature of the heat carrier reaches 150-160°C. It has been stated that for intensification of the thermal process during sterilization of tinned fish with liquid filling it is preferable to turn a tin from bottom to top. This operation helps to increase the driving power of the process and to shorten warming time. Besides, high-temperature sterilization carried out according to experimental modes, where the number of tin turnovers is calculated, greatly shortens processing time and improves quality of the product. In this case there is no superheating, all tins are evenly heated. The study results will contribute to equipment modernization and to preserving valuable food qualities.

Behavior of Some Varieties in the Kernel Group to the Attack of the Main Pathogens

2018 ◽  
Vol 12 (2) ◽  
pp. 1-7
Author(s):  
Sînziana Venera Morărița
Keyword(s):  
Chemical Composition ◽  
Climatic Conditions ◽  
Complex Chemical ◽  
Complex Chemical Composition ◽  
Large Production ◽  
Special Quality

Abstract Although relatively recent, peach culture has grown great in our country due to the special quality of the fruit, its very complex chemical composition and the large production that can be obtained without much effort. Peach is a species slightly adapted to our climatic conditions, suffers from winter frost, but can provide productive and long productions of 10-15 years.

Effect of High Temperature on Wear Behavior of Stir Cast Aluminium/Boron Carbide Composites

2020 ◽  
Vol 22 (4) ◽  
pp. 1031-1046
Author(s):  
X. Canute ◽  
M. C. Majumder
Keyword(s):  
High Temperature ◽  
Wear Rate ◽  
Boron Carbide ◽  
Wear Behavior ◽  
Base Alloy ◽  
Weight Fraction ◽  
Sliding Velocity ◽  
Wear Properties ◽  
High Temperature Wear ◽  
The Matrix

AbstractThe need for development of high temperature wear resistant composite materials with superior mechanical properties and tribological properties is increasing significantly. The high temperature wear properties of aluminium boron carbide composites was evaluated in this investigation. The effect of load, sliding velocity, temperature and reinforcement percentage on wear rate was determined by the pin heating method using pin heating arrangement. The size and structure of base alloy particles change considerably with an increase of boron carbide particles. The wettability and interface bonding between the matrix and reinforcement enhanced by the addition of potassium flurotitanate. ANOVA technique was used to study the effect of input parameters on wear rate. The investigation reveals that the load had higher significance than sliding velocity, temperature and weight fraction. The pin surface was studied with a high-resolution scanning electron microscope. Regression analysis revealed an extensive association between control parameters and response. The developed composites can be used in the production of automobile parts requiring high wear, frictional and thermal resistance.

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