The Experts below are selected from a list of 1248 Experts worldwide ranked by ideXlab platform

D Landolt - One of the best experts on this subject based on the ideXlab platform.

  • effect of an inhibitive pigment zinc aluminum phosphate zap on the corrosion mechanisms of steel in waterborne coatings
    Progress in Organic Coatings, 2006
    Co-Authors: M Hernandez, J Genesca, Jorge Uruchurtu, F Galliano, D Landolt
    Abstract:

    Abstract The effect of the inhibitive pigment ZAP on waterborne paint systems was studied by means of impedance technique and Raman spectroscopy. The protective mechanism given by the action of ZAP in saline media onto low-carbon steel panels is attributed to the formation of a thin zinc-sodium-phosphate layer under cathodic delamination conditions. The chemical interactions between the waterborne paint systems and the metal substrate at the curing time and during the delamination tests were investigated by Raman spectroscopy. The layer developed on the Delaminated Area is thought to be a phosphate layer known as α-hopeite. This film is though to arise from a dissolution–precipitation mechanism in alkaline media.

  • Mechanism of cathodic delamination control of zinc–aluminum phosphate pigment in waterborne coatings
    Corrosion Science, 2004
    Co-Authors: M.a. Hernández, F Galliano, D Landolt
    Abstract:

    Abstract The propagation of the cathodic delamination and blistering was studied for different waterborne paint systems, with or without the zinc aluminum phosphate (ZAP) pigment. The mechanism by which ZAP reacts at the metal–coating interface to improve coating performance against cathodic delamination and blister formation was investigated by means of scanning acoustic microscopy (SAM), pull-off test and surface analysis. The presence of the pigment clearly enhanced the adhesion and delamination resistance of the coating upon immersion. It has been evidenced how the pH buffer properties of the ZAP pigment play an important role in reducing the advancement of the delamination front. A compact film constituted of zinc and sodium phosphates was found, on the substrate surface, solely within the Delaminated Area. The precipitation of this phosphate layer on the cathodic sites is thought to polarize the cathodic reaction, contributing to slowing down the delamination reaction.

Pietro Russo - One of the best experts on this subject based on the ideXlab platform.

  • ultrasonic damage investigation on woven jute poly lactic acid composites subjected to low velocity impact
    Composites Part B-engineering, 2017
    Co-Authors: Ilaria Papa, V Lopresto, Giorgio Simeoli, A Langella, Pietro Russo
    Abstract:

    Abstract In the present contribution, particular attention is devoted to the fabrication and characterization of fully bio laminated structures based on a commercial poly (lactic acid) (PLA) including a jute fabric as reinforcements, even because of the limited availability of the reference literature. An ultrasonic technique is used to investigate the delamination caused by low velocity impact tests, on plates obtained by typical film stacking and compression molding techniques. The square specimens, 100*100 mm, were impacted by a falling dart machine at five increasing impact energy values of 2 J, 5 J, 10 J, 12 J, and 15 J. The delamination is investigated by the very commonly used Ultra Sound technique employing a linear phased array probe. The Delaminated Area is correlated with both the impact energy and the measured indentation depth. The results showed a threshold energy for the beginning of the internal damage. Moreover, a linear relationship between the Delaminated Area, the energy and the indentation depth was found.

  • Ultrasonic damage investigation on woven jute/poly (lactic acid) composites subjected to low velocity impact
    Composites Part B: Engineering, 2017
    Co-Authors: Ilaria Papa, V Lopresto, Giorgio Simeoli, A Langella, Pietro Russo
    Abstract:

    Abstract In the present contribution, particular attention is devoted to the fabrication and characterization of fully bio laminated structures based on a commercial poly (lactic acid) (PLA) including a jute fabric as reinforcements, even because of the limited availability of the reference literature. An ultrasonic technique is used to investigate the delamination caused by low velocity impact tests, on plates obtained by typical film stacking and compression molding techniques. The square specimens, 100*100 mm, were impacted by a falling dart machine at five increasing impact energy values of 2 J, 5 J, 10 J, 12 J, and 15 J. The delamination is investigated by the very commonly used Ultra Sound technique employing a linear phased array probe. The Delaminated Area is correlated with both the impact energy and the measured indentation depth. The results showed a threshold energy for the beginning of the internal damage. Moreover, a linear relationship between the Delaminated Area, the energy and the indentation depth was found.

Ilaria Papa - One of the best experts on this subject based on the ideXlab platform.

  • Impact behavior of basalt/epoxy composite: Comparison between flat and twill fabric
    2018
    Co-Authors: Ilaria Papa, M.r. Ricciardi, V. Antonucci, A. Langella, V. Lopresto
    Abstract:

    Two types of basalt fibre reinforced epoxy laminates were realized by overlapping flat and twill woven basalt fabrics by resin infusion. Rectangular specimens, cut from the panels were impacted at penetration and at increasing energy values, to investigate the damage onset and propagation. A non-destructive technique, Ultrasound testing (UT), was adopted to investigate the internal damage. Despite the difficulties to obtain information by UT method due to the high amount of signal absorbed, the technique, properly calibrated, proved to be very useful in providing information about the presence, the shape and the extent of the delaminations. The results were compared at the aim to investigate the effect of the fiber architecture (textile). The experimental results indicate a similar impact behavior between basalt flat and twill composites but in the case of the twill a minor Delaminated Area was detected, even if a higher absorbed energy was recordedTwo types of basalt fibre reinforced epoxy laminates were realized by overlapping flat and twill woven basalt fabrics by resin infusion. Rectangular specimens, cut from the panels were impacted at penetration and at increasing energy values, to investigate the damage onset and propagation. A non-destructive technique, Ultrasound testing (UT), was adopted to investigate the internal damage. Despite the difficulties to obtain information by UT method due to the high amount of signal absorbed, the technique, properly calibrated, proved to be very useful in providing information about the presence, the shape and the extent of the delaminations. The results were compared at the aim to investigate the effect of the fiber architecture (textile). The experimental results indicate a similar impact behavior between basalt flat and twill composites but in the case of the twill a minor Delaminated Area was detected, even if a higher absorbed energy was recorded

  • ultrasonic damage investigation on woven jute poly lactic acid composites subjected to low velocity impact
    Composites Part B-engineering, 2017
    Co-Authors: Ilaria Papa, V Lopresto, Giorgio Simeoli, A Langella, Pietro Russo
    Abstract:

    Abstract In the present contribution, particular attention is devoted to the fabrication and characterization of fully bio laminated structures based on a commercial poly (lactic acid) (PLA) including a jute fabric as reinforcements, even because of the limited availability of the reference literature. An ultrasonic technique is used to investigate the delamination caused by low velocity impact tests, on plates obtained by typical film stacking and compression molding techniques. The square specimens, 100*100 mm, were impacted by a falling dart machine at five increasing impact energy values of 2 J, 5 J, 10 J, 12 J, and 15 J. The delamination is investigated by the very commonly used Ultra Sound technique employing a linear phased array probe. The Delaminated Area is correlated with both the impact energy and the measured indentation depth. The results showed a threshold energy for the beginning of the internal damage. Moreover, a linear relationship between the Delaminated Area, the energy and the indentation depth was found.

  • Ultrasonic damage investigation on woven jute/poly (lactic acid) composites subjected to low velocity impact
    Composites Part B: Engineering, 2017
    Co-Authors: Ilaria Papa, V Lopresto, Giorgio Simeoli, A Langella, Pietro Russo
    Abstract:

    Abstract In the present contribution, particular attention is devoted to the fabrication and characterization of fully bio laminated structures based on a commercial poly (lactic acid) (PLA) including a jute fabric as reinforcements, even because of the limited availability of the reference literature. An ultrasonic technique is used to investigate the delamination caused by low velocity impact tests, on plates obtained by typical film stacking and compression molding techniques. The square specimens, 100*100 mm, were impacted by a falling dart machine at five increasing impact energy values of 2 J, 5 J, 10 J, 12 J, and 15 J. The delamination is investigated by the very commonly used Ultra Sound technique employing a linear phased array probe. The Delaminated Area is correlated with both the impact energy and the measured indentation depth. The results showed a threshold energy for the beginning of the internal damage. Moreover, a linear relationship between the Delaminated Area, the energy and the indentation depth was found.

F Galliano - One of the best experts on this subject based on the ideXlab platform.

  • effect of an inhibitive pigment zinc aluminum phosphate zap on the corrosion mechanisms of steel in waterborne coatings
    Progress in Organic Coatings, 2006
    Co-Authors: M Hernandez, J Genesca, Jorge Uruchurtu, F Galliano, D Landolt
    Abstract:

    Abstract The effect of the inhibitive pigment ZAP on waterborne paint systems was studied by means of impedance technique and Raman spectroscopy. The protective mechanism given by the action of ZAP in saline media onto low-carbon steel panels is attributed to the formation of a thin zinc-sodium-phosphate layer under cathodic delamination conditions. The chemical interactions between the waterborne paint systems and the metal substrate at the curing time and during the delamination tests were investigated by Raman spectroscopy. The layer developed on the Delaminated Area is thought to be a phosphate layer known as α-hopeite. This film is though to arise from a dissolution–precipitation mechanism in alkaline media.

  • Mechanism of cathodic delamination control of zinc–aluminum phosphate pigment in waterborne coatings
    Corrosion Science, 2004
    Co-Authors: M.a. Hernández, F Galliano, D Landolt
    Abstract:

    Abstract The propagation of the cathodic delamination and blistering was studied for different waterborne paint systems, with or without the zinc aluminum phosphate (ZAP) pigment. The mechanism by which ZAP reacts at the metal–coating interface to improve coating performance against cathodic delamination and blister formation was investigated by means of scanning acoustic microscopy (SAM), pull-off test and surface analysis. The presence of the pigment clearly enhanced the adhesion and delamination resistance of the coating upon immersion. It has been evidenced how the pH buffer properties of the ZAP pigment play an important role in reducing the advancement of the delamination front. A compact film constituted of zinc and sodium phosphates was found, on the substrate surface, solely within the Delaminated Area. The precipitation of this phosphate layer on the cathodic sites is thought to polarize the cathodic reaction, contributing to slowing down the delamination reaction.

J. López-puente - One of the best experts on this subject based on the ideXlab platform.

  • Experimental analysis of ice sphere impacts on unidirectional carbon/epoxy laminates
    International Journal of Impact Engineering, 2016
    Co-Authors: J. Pernas-sánchez, J.a. Artero-guerrero, D. Varas, J. López-puente
    Abstract:

    Abstract This work analyses the behaviour of carbon/epoxy unidirectional laminates subjected to high velocity impacts of ice spheres. To this end, ice projectiles were launched against composite laminates in a wide range of velocities ( 50 − 250 m / s ). Two different ice diameters (40 and 50 mm) and two laminate thicknesses (4 and 6 mm) were considered. The internal damage was measured using both destructive and non-destructive techniques, which allow an accurate quantification of the Delaminated Area. Finally the influence of the different parameters considered on the damage of the laminate is analysed by means of a dimensionless variable.

  • Simulations of High Velocity Impacts of Ice on Carbon/Epoxy Composite Laminates
    Applied Mechanics and Materials, 2014
    Co-Authors: J. Pernas-sánchez, J.a. Artero-guerrero, D. Varas, J. López-puente
    Abstract:

    In this work simulations of high velocity impacts of ice spheres on carbon/epoxy laminates are accomplished. The Drucker-Prager model has been chosen to describe the mechanical behavior of the ice under high velocity impact conditions. Results have been validated by means of experimental tests performed in a wide range of impact velocities. The Delaminated Area was chosen as comparison variable, and reflects that the model predicts adequately the impact process.