scholarly journals Microstructure and mechanical properties of aluminium alloy coatings on alumina applied by friction surfacing

2020 ◽  
pp. 146442072096561
Author(s):  
HB Atil ◽  
M Leonhardt ◽  
RJ Grant ◽  
S Barrans
Keyword(s):  
Aluminium Alloy ◽  
Material Properties ◽  
Laser Scanning ◽  
Coefficient Of Thermal Expansion ◽  
Molten Metals ◽  
Joint Zone ◽  
Friction Surfacing ◽  
Shock Resistance ◽  
Thermally Sprayed ◽  
Sprayed Coatings

By combining lightweight metal alloys with ceramics, it is possible to adapt material properties on stressed parts and thus increase stiffness and/or change the thermal resistance: yet joining such materials is problematic due to the poor wettability of ceramics by molten metals. In this work, the technique of friction surfacing is used to connect alumina (Al2O3) with an aluminium alloy (EN-AW 5083). Despite the fact that Al2O3 has a relatively high coefficient of thermal expansion and a low thermal shock resistance, specimens have been produced showing encouraging results. In order to compensate for these material properties the substrate was preheated to a minimum of 150°C. In tests bonding strengths reached 47.8 MPa and coating thicknesses of 213 μm were achieved; results which are comparable with conventional thermally sprayed coatings. Bonding strengths were determined by using a pull-off adhesion tester and the coating thickness was measured with a laser scanning microscope. Analysis of the joint zone shows no clear evidence of chemical reactions (intermetallic compounds) or diffusion. Mechanical interlocking can only be shown to be accountable for 16% of the bonding strength with investigations turning towards van der Waals forces and their contribution to adhesion.

Thermal Expansion of Thermally Sprayed Coatings

1998 ◽  
Author(s):  
M. Beghini ◽  
L. Bertini ◽  
F. Frendo
Keyword(s):  
Thermal Expansion ◽  
Coefficient Of Thermal Expansion ◽  
Video Camera ◽  
Beam Model ◽  
Accuracy Of Measurements ◽  
Point Bend ◽  
Measured Length ◽  
Four Point Bend Test ◽  
Thermally Sprayed ◽  
Sprayed Coatings

Abstract The coefficient of thermal expansion (CTE) of a NiCoCrAlY coating was investigated in this work. The CTE was inferred from the measured length variations of coated prismatic symmetric specimens (i.e. having the coating on two opposite surfaces) at various temperature increments. The elongation of the specimen was evaluated from the relative positions of two markers, which was recorded during the test by a CCD video camera; analysis with subpixeling technique allowed high resolution in the dilatation measurements. Analytical relationships used to determine the coating's CTE were based on the simple multilayer beam model; the temperature dependent elastic moduli of the layers had been determined by four point bend test in a previous work. Coated specimens were employed having different substrate thicknesses in order to check the accuracy of measurements.

scholarly journals Thermal Spray Deposition and Evaluation of Low-Z Coatings

1996 ◽  
Author(s):  
R.D. Seals ◽  
C.J. Swindeman ◽  
R.L. White
Keyword(s):  
Coefficient Of Thermal Expansion ◽  
Spray Deposition ◽  
Impact Resistance ◽  
Ball Impact ◽  
Thermally Sprayed Coatings ◽  
Before And After ◽  
Aluminum Substrates ◽  
Thermally Sprayed ◽  
Sprayed Coatings ◽  
Boron Carbide B4c

Abstract Thermally-sprayed low-Z coatings of boron carbide (B4C) on aluminum substrates were investigated as candidate materials for first-wall reactor protective surfaces. Comparisons were made to thermally-sprayed coatings of boron, MgAl204, Al2O3, and composites. Graded bond layers were applied to mitigate coefficient of thermal expansion mismatch. Microstructures, thermal diffusivity before and after thermal shock loading, steel ball impact resistance, CO2 pellet cleaning and erosion tolerance, phase content, stoichiometry by Rutherford backscattering spectroscopy (RBS), and relative tensile strengths were measured.

Adhesion of HVOF Sprayed Diamond-Containing Nanostructured Composite Coating

2002 ◽  
Vol 740 ◽  
Author(s):  
Maksim V. Kireitseu ◽  
Ion Nemerenco
Keyword(s):  
Aluminum Oxide ◽  
Composite Coating ◽  
Composite Coatings ◽  
High Accuracy ◽  
Nanostructured Composite ◽  
Thermally Sprayed Coatings ◽  
Shock Resistance ◽  
Thermally Sprayed ◽  
Sprayed Coatings ◽  
Accuracy Speed

ABSTRACTIn the present paper mechanical properties of HVOF sprayed diamonds-containing aluminum oxide composite coating have been investigated. Crystallographic and morphologic texture was measured. Diamonds nanoparticles may improve fracture resistance of aluminum oxide-based coating. Investigations of thermally sprayed coatings by the test revealed high accuracy, speed and reliability of the test. It is also thought that the composite coatings will have better thermal conductivity and thermal shock resistance than that of aluminum oxide-based coatings.

INVESTIGATION OF BIAXIAL ELASTIC MODULUS AND CTE OF BaTiO3 FILMS

2009 ◽  
Vol 23 (24) ◽  
pp. 4933-4941
Author(s):  
GUI-FANG HUANG ◽  
WEI-QING HUANG ◽  
LING-LING WANG ◽  
ZHONG XIE ◽  
BING-SUO ZOU ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Thermal Cycle ◽  
Laser Scanning ◽  
Stress Measurement ◽  
Coefficient Of Thermal Expansion ◽  
Bulk Material ◽  
Good Reliability ◽  
Scanning Method ◽  
As Stress

To develop high-quality film device with good reliability, it is often essential to be able to evaluate the parameters such as stress, the biaxial elastic modulus, and coefficient of thermal expansion (CTE) of film. Based on the stress measurement in situ during the thermal cycle by laser scanning method, two techniques were used to measure the biaxial elastic modulus and CTE of BaTiO 3 films deposited on substrate. The value of the biaxial elastic modulus and CTE for BaTiO 3 films determined from two methods is close, in which the biaxial elastic modulus of BaTiO 3 films is higher than that of corresponding bulk while the CTE of BaTiO 3 films is a little smaller than that of bulk material.

Sign in / Sign up

Export Citation Format

Share Document