Research

8287 KiB

Open AccessArticle

Study of a Particle Based Films Cure Process by High-Frequency Eddy Current Spectroscopy

by Iryna Patsora, Henning Heuer, Susanne Hillmann and Dmytro Tatarchuk

Coatings 2017, 7(1), 3; https://doi.org/10.3390/coatings7010003 - 28 Dec 2016

Cited by 1 | Viewed by 6262

Particle-based films are today an important part of various designs and they are implemented in structures as conductive parts, i.e., conductive paste printing in the manufacture of Li-ion batteries, solar cells or resistive paste printing in IC. Recently, particle based films were also [...] Read more.

Particle-based films are today an important part of various designs and they are implemented in structures as conductive parts, i.e., conductive paste printing in the manufacture of Li-ion batteries, solar cells or resistive paste printing in IC. Recently, particle based films were also implemented in the 3D printing technique, and are particularly important for use in aircraft, wind power, and the automotive industry when incorporated onto the surface of composite structures for protection against damages caused by a lightning strike. A crucial issue for the lightning protection area is to realize films with high homogeneity of electrical resistance where an in-situ noninvasive method has to be elaborated for quality monitoring to avoid undesirable financial and time costs. In this work the drying process of particle based films was investigated by high-frequency eddy current (HFEC) spectroscopy in order to work out an automated in-situ quality monitoring method with a focus on the electrical resistance of the films. Different types of particle based films deposited on dielectric and carbon fiber reinforced plastic substrates were investigated in the present study and results show that the HFEC method offers a good opportunity to monitor the overall drying process of particle based films. Based on that, an algorithm was developed, allowing prediction of the final electrical resistance of the particle based films throughout the drying process, and was successfully implemented in a prototype system based on the EddyCus^® HFEC device platform presented in this work. This prototype is the first solution for a portable system allowing HFEC measurement on huge and uneven surfaces. Full article

(This article belongs to the Special Issue Advances in Coatings Characterization)

► Show Figures

Figure 1

1728 KiB

Open AccessArticle

Structural Study of Silica Coating Thin Layers Prepared from Perhydropolysilazane: Substrate Dependence and Water Penetration Structure

by Tomotake Niizeki, Sachiko Nagayama, Yoshio Hasegawa, Noboru Miyata, Masae Sahara and Kazuhiro Akutsu

Coatings 2016, 6(4), 64; https://doi.org/10.3390/coatings6040064 - 19 Nov 2016

Cited by 14 | Viewed by 7696

Abstract

The structure of perhydropolysilazane (PHPS)-derived silica (PDS) waterproof thin layers synthesized by curing at 60 °C for 1 h and allowed to stand for 48 h at 20 °C on various kinds of substrates was studied. Neutron reflectivity (NR) analysis suggested that uniform [...] Read more.

The structure of perhydropolysilazane (PHPS)-derived silica (PDS) waterproof thin layers synthesized by curing at 60 °C for 1 h and allowed to stand for 48 h at 20 °C on various kinds of substrates was studied. Neutron reflectivity (NR) analysis suggested that uniform PDS thin layers were synthesized on the substrates, and the density of the layers varied depending on the type of substrate. Additionally, since the change in PDS density is correlated with the pK_a value of the OH group on the substrate, it can be suggested that the acidity of the substrate would be one of the main factors determining the density of the coated PDS thin layers. For the water penetration structure study, NR analysis revealed that the depth of water penetration into the PDS layers was below 500 Å, and the hydration number of the SiO₂ molecule was estimated to be 8.0–9.0. From these results, we concluded that water penetration occurred by the formation of water-pool structures in the PDS layers, and the randomly formed nano-air holes lead to a reduction in the probability of water penetration into the deep regions of the PDS layers. Full article

(This article belongs to the Special Issue Advances in Coatings Characterization)

► Show Figures

Figure 1

3836 KiB

Open AccessCommunication

Cylindrical Three-Dimensional Porous Anodic Alumina Networks

by Pedro M. Resende, Ruy Sanz, Alejandra Ruiz-de Clavijo, Olga Caballero-Calero and Marisol Martin-Gonzalez

Coatings 2016, 6(4), 59; https://doi.org/10.3390/coatings6040059 - 09 Nov 2016

Cited by 9 | Viewed by 4790

Abstract

The synthesis of a conformal three-dimensional nanostructure based on porous anodic alumina with transversal nanopores on wires is herein presented. The resulting three-dimensional network exhibits the same nanostructure as that obtained on planar geometries, but with a macroscopic cylindrical geometry. The morphological analysis [...] Read more.

The synthesis of a conformal three-dimensional nanostructure based on porous anodic alumina with transversal nanopores on wires is herein presented. The resulting three-dimensional network exhibits the same nanostructure as that obtained on planar geometries, but with a macroscopic cylindrical geometry. The morphological analysis of the nanostructure revealed the effects of the initial defects on the aluminum surface and the mechanical strains on the integrity of the three-dimensional network. The results evidence the feasibility of obtaining 3D porous anodic alumina on non-planar aluminum substrates. Full article

(This article belongs to the Special Issue Advances in Coatings Characterization)

► Show Figures

Figure 1

5280 KiB

Open AccessArticle

Statistical Contact Angle Analyses with the High-Precision Drop Shape Analysis (HPDSA) Approach: Basic Principles and Applications

by Florian Heib and Michael Schmitt

Coatings 2016, 6(4), 57; https://doi.org/10.3390/coatings6040057 - 06 Nov 2016

Cited by 74 | Viewed by 14183

Abstract

Surface science, which includes the preparation, development and analysis of surfaces and coatings, is essential in both fundamental and applied as well as in engineering and industrial research. Contact angle measurements using sessile drop techniques are commonly used to characterize coated surfaces or [...] Read more.

Surface science, which includes the preparation, development and analysis of surfaces and coatings, is essential in both fundamental and applied as well as in engineering and industrial research. Contact angle measurements using sessile drop techniques are commonly used to characterize coated surfaces or surface modifications. Well-defined surfaces structures at both nanoscopic and microscopic level can be achieved but the reliable characterization by means of contact angle measurements and their interpretation often remains an open question. Thus, we focused our research effort on one main problem of surface science community, which is the determination of correct and valid definitions and measurements of contact angles. In this regard, we developed the high-precision drop shape analysis (HPDSA), which involves a complex transformation of images from sessile drop experiments to Cartesian coordinates and opens up the possibility of a physically meaningful contact angle calculation. To fulfill the dire need for a reproducible contact angle determination/definition, we developed three easily adaptable statistical analyses procedures. In the following, the basic principles of HPDSA will be explained and applications of HPDSA will be illustrated. Thereby, the unique potential of this analysis approach will be illustrated by means of selected examples. Full article

(This article belongs to the Special Issue Advances in Coatings Characterization)

► Show Figures

Graphical abstract

3248 KiB

Open AccessArticle

Assessing the Protective Quality of Wax Coatings on Bronze Sculptures Using Hydrogel Patches in Impedance Measurements

by Alice H. England, Kathryn N. Hosbein, Capri A. Price, Morgan K. Wylder, Kenna S. Miller and Tami Lasseter Clare

Coatings 2016, 6(4), 45; https://doi.org/10.3390/coatings6040045 - 13 Oct 2016

Cited by 7 | Viewed by 5444

Abstract

In this work, we used chemically cross-linked acrylamide-based hydrogel patches that have been specifically developed for use as solid electrolytes in Electrochemical Impedance Spectroscopy to measure the impedance of two waxed bronze sculptures at the Seattle Art Museum’s (SAM) Olympic Sculpture Park (OSP) [...] Read more.

In this work, we used chemically cross-linked acrylamide-based hydrogel patches that have been specifically developed for use as solid electrolytes in Electrochemical Impedance Spectroscopy to measure the impedance of two waxed bronze sculptures at the Seattle Art Museum’s (SAM) Olympic Sculpture Park (OSP) and compare those results to laboratory test panels. We determined that the impedance response in the frequency range in which measurements may be taken (10 kHz to 1 MHz) is mostly capacitive and that a freshly applied wax coating should ideally be less than 1 nF·cm⁻² for optimal protective performance. Full article

(This article belongs to the Special Issue Advances in Coatings Characterization)

► Show Figures

Graphical abstract

Review

Jump to: Research, Other

5630 KiB

Open AccessReview

Thickness Measurement Methods for Physical Vapor Deposited Aluminum Coatings in Packaging Applications: A Review

by Martina Lindner and Markus Schmid

Coatings 2017, 7(1), 9; https://doi.org/10.3390/coatings7010009 - 14 Jan 2017

Cited by 19 | Viewed by 12266

Abstract

The production of barrier packaging materials, e.g., for food, by physical vapor deposition (PVD) of inorganic coatings such as aluminum on polymer substrates is an established and well understood functionalization technique today. In order to achieve a sufficient barrier against gases, a coating [...] Read more.

The production of barrier packaging materials, e.g., for food, by physical vapor deposition (PVD) of inorganic coatings such as aluminum on polymer substrates is an established and well understood functionalization technique today. In order to achieve a sufficient barrier against gases, a coating thickness of approximately 40 nm aluminum is necessary. This review provides a holistic overview of relevant methods commonly used in the packaging industry as well as in packaging research for determining the aluminum coating thickness. The theoretical background, explanation of methods, analysis and effects on measured values, limitations, and resolutions are provided. In industrial applications, quartz micro balances (QCM) and optical density (OD) are commonly used for monitoring thickness homogeneity. Additionally, AFM (atomic force microscopy), electrical conductivity, eddy current measurement, interference, and mass spectrometry (ICP-MS) are presented as more packaging research related methods. This work aims to be used as a guiding handbook regarding the thickness measurement of aluminum coatings for packaging technologists working in the field of metallization. Full article

(This article belongs to the Special Issue Advances in Coatings Characterization)

► Show Figures

Figure 1

1400 KiB

Open AccessReview

Low Energy Atomic Photodesorption from Organic Coatings

by Alessandro Lucchesini, Silvia Gozzini, Carmela Marinelli and Luca Marmugi

Coatings 2016, 6(4), 47; https://doi.org/10.3390/coatings6040047 - 17 Oct 2016

Cited by 8 | Viewed by 5914

Abstract

Organic coatings have been widely used in atomic physics during the last 50 years because of their mechanical properties, allowing preservation of atomic spins after collisions. Nevertheless, this did not produce detailed insight into the characteristics of the coatings and their dynamical interaction [...] Read more.

Organic coatings have been widely used in atomic physics during the last 50 years because of their mechanical properties, allowing preservation of atomic spins after collisions. Nevertheless, this did not produce detailed insight into the characteristics of the coatings and their dynamical interaction with atomic vapors. This has changed since the 1990s, when their adsorption and desorption properties triggered a renewed interest in organic coatings. In particular, a novel class of phenomena produced by non-destructive light-induced desorption of atoms embedded in the coating surface was observed and later applied in different fields. Nowadays, low energy non-resonant atomic photodesorption from organic coatings can be considered an almost standard technique whenever large densities of atomic vapors or fast modulation of their concentration are required. In this paper, we review the steps that led to this widespread diffusion, from the preliminary observations to some of the most recent applications in fundamental and applied physics. Full article

(This article belongs to the Special Issue Advances in Coatings Characterization)

► Show Figures