“…Its density, as measured by Archimedes's method, was found to be 13.4 g/cm 3 , which is very close to the value of 13.5 g/cm 3 obtained by laser-ultrasonics. The Young's modulus was measured for this sample by a three-point bending test and found to be 318 GPa with an estimated accuracy of ±10%.…”
Section: Density and Elastic Modulus Measurements Via Laser-ultrasonicssupporting
confidence: 81%
“…Previous works on ultrasound for the characterization of thermal sprayed coatings have shown the great potential of the technique to measure various properties like elastic constants (Ref [1][2][3][4][5][6][7][8], thickness (Ref 1,4) and adhesion (Ref 5,9,10). The ultrasonic waves propagate through the thickness of the coating (bulk waves) or along the coating (surface waves).…”
Section: Nondestructive Evaluation Of Thermal Spray Coatingsmentioning
confidence: 99%
“…In a previous paper (Ref 3), the elastic property measurements of WC-Co and TiO 2 coatings with the laserultrasonic technique and a comparison of the results with measurements obtained with the Knoop indentation technique were presented. The laser-ultrasonic technique was used to generate and detect surface acoustic waves of both Rayleigh and longitudinal types in the high-frequency limit (waves propagate only in the coating with no influence of the substrate).…”
Section: Nondestructive Evaluation Of Thermal Spray Coatingsmentioning
In-situ simultaneous measurement of thickness, elastic moduli and density of thermal sprayed WC-Co coatings by laserultrasonics Bescond, C.; Kruger, S. E.; Lévesque, D.; Lima, R. S.; Marple, B. R. A method for simultaneous nondestructive evaluation of WC-Co coating thickness, elastic moduli, and density is presented. The technique, known as laser-ultrasonics, is used to generate and detect surface acoustic waves in a noncontact and nondestructive manner. The surface acoustic wave velocity dependence on frequency is compared to a model and an optimization procedure is used to evaluate the coating properties. The results obtained demonstrate the ability of the technique to simultaneously determine such properties with a single and possibly in situ measurement.
“…Its density, as measured by Archimedes's method, was found to be 13.4 g/cm 3 , which is very close to the value of 13.5 g/cm 3 obtained by laser-ultrasonics. The Young's modulus was measured for this sample by a three-point bending test and found to be 318 GPa with an estimated accuracy of ±10%.…”
Section: Density and Elastic Modulus Measurements Via Laser-ultrasonicssupporting
confidence: 81%
“…Previous works on ultrasound for the characterization of thermal sprayed coatings have shown the great potential of the technique to measure various properties like elastic constants (Ref [1][2][3][4][5][6][7][8], thickness (Ref 1,4) and adhesion (Ref 5,9,10). The ultrasonic waves propagate through the thickness of the coating (bulk waves) or along the coating (surface waves).…”
Section: Nondestructive Evaluation Of Thermal Spray Coatingsmentioning
confidence: 99%
“…In a previous paper (Ref 3), the elastic property measurements of WC-Co and TiO 2 coatings with the laserultrasonic technique and a comparison of the results with measurements obtained with the Knoop indentation technique were presented. The laser-ultrasonic technique was used to generate and detect surface acoustic waves of both Rayleigh and longitudinal types in the high-frequency limit (waves propagate only in the coating with no influence of the substrate).…”
Section: Nondestructive Evaluation Of Thermal Spray Coatingsmentioning
In-situ simultaneous measurement of thickness, elastic moduli and density of thermal sprayed WC-Co coatings by laserultrasonics Bescond, C.; Kruger, S. E.; Lévesque, D.; Lima, R. S.; Marple, B. R. A method for simultaneous nondestructive evaluation of WC-Co coating thickness, elastic moduli, and density is presented. The technique, known as laser-ultrasonics, is used to generate and detect surface acoustic waves in a noncontact and nondestructive manner. The surface acoustic wave velocity dependence on frequency is compared to a model and an optimization procedure is used to evaluate the coating properties. The results obtained demonstrate the ability of the technique to simultaneously determine such properties with a single and possibly in situ measurement.
“…3b. It is important to point out that a previous work indicated a "good" correlation between the E values measured via Knoop indentation and the laser-ultrasonics technique for APS and HVOF-sprayed TiO 2 coatings produced from conventional fused and crushed powders [19]. …”
Section: Elastic Modulus Values Measured Via Laser-ultrasonicsmentioning
It is widely recognized by the scientific community that thermal spray coatings exhibit anisotropic behaviour of mechanical properties, e.g., the elastic modulus values of the coating in-plane (i.e., parallel to the substrate surface) or through-thickness (i.e., perpendicular to the substrate surface) will tend to be significantly different due to their anisotropic microstructures. This work shows that thermally sprayed ceramic coatings may exhibit isotropic mechanical behaviour similar to that of bulk materials even when exhibiting the typical anisotropic coating microstructure. Elastic modulus values on the in-plane and through-thickness directions were measured via Knoop indention and laser-ultrasonic techniques on a coating produced via flame spray (FS) using a nanostructured titania (TiO 2 ) powder. No significant differences were found between the coating directions. In addition, four major cracks with similar lengths were observed originating near or at the corners of Vickers indentation impressions on the coating cross-section (i.e., a typical characteristic of bulk ceramics), instead of two major cracks propagating parallel to the substrate surface, which is normally the case for these types of coatings. It was observed by scanning electron microscopy (SEM) that coatings tended to exhibit an isotropic behaviour when the average length of microcracks within the coating structure oriented perpendicular to the substrate surface was about twice that of the microcracks aligned parallel to the substrate surface. Modelling, based on scalar crack densities of horizontal and vertical cracks, was also used to estimate when thermal spray coatings tend to exhibit isotropic behaviour. Crown
“…Se seleccionaron 13 huellas aceptables por la norma de las 20 realizadas. Por otro lado, se utilizó un indentador Knoop para hallar la dureza Knoop (HK), la que fue utilizada para calcular el módulo de elasticidad (E), utilizando el método de Marshall [26]. Para el ensayo se hicieron 20 indentaciones Knoop a una carga de 125 g. La carga fue aplicada durante 15 s y las huellas fueron distribuidas en toda la muestra a una distancia de aproximadamente 150 µm una de la otra, para evitar la influencia de las indentaciones vecinas.…”
Section: Proceso De Proyección Térmicaunclassified
Microestructura y propiedades mecánicas por microindentación y nanoindentación de un recubrimiento de circona estabilizada con itria (4,5% en mol) elaborado por plasma atmosférico a partir de suspensiones
RESUMENEn este trabajo se analizó la relación entre la microestructura de un recubrimiento de 4,5% en mol de circona estabilizada con itria (4.5YSZ) con sus propiedades mecánicas medidas por nanoindentación y microindentación. Los recubrimientos fueron elaborados por la técnica de proyección térmica por plasma atmosférico a partir de una suspensión de etanol y dos tipos de polvos (3 y 8% en mol de YSZ) con partículas de tamaño nanométrico. El análisis de la microestructura de la sección trasversal del recubrimiento de 4.5YSZ reveló una estructura bimodal, la que estaba compuesta de una zona con partículas semifundidas (ZS) y otra zona compuesta de lamelas con un alto grado de fusión (ZF). Los ensayos de nanoindentación mostraron una distribución Weibull bimodal para la dureza y monomodal para el módulo de elasticidad, lo que está relacionada con su estructura. Los ensayos microindentación (microdureza Vickers y módulo de elasticidad: E) presentaron una distribución Weibull monomodal. Estos resultados de microindentación estuvieron influenciados por el área de contacto de las zonas indentadas, ya que estas tomaban las dos zonas microestructurales (ZF y ZS) del recubrimiento de 4.5YSZ revelando una medición global de sus propiedades mecánicas.Palabras clave: Proyección térmica por plasma, suspensiones de nanopartículas, recubrimiento de circona, nanoindentación, microindentación.
ABSTRACTIn this paper the microstructure of 4.5 mol%
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