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

Lindner, Martina; Schmid, Markus

doi:10.3390/coatings7010009

Cited by 19 publications

(14 citation statements)

References 106 publications

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“…Based on the stripped-off sample area A, the nominal thickness of the aluminum layer d NOMINAL was calculated using the determined concentration of aluminum c and a bulk value for density (δ lit ) of 2.7 g/cm 3 taken from the literature [22], as shown in Equation 4. The coating weight (cw NOMINAL ) [g/m 2 ] was calculated according to Equation (5) [23].…”

Section: Inductively-coupled Plasma-mass Spectrometry (Icp-ms)mentioning

confidence: 99%

Hygroexpansion and Surface Roughness Cause Defects and Increase the Electrical Resistivity of Physical Vapor Deposited Aluminum Coatings on Paper

et al. 2019

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Aluminum coatings, which are applied by physical vapor deposition (PVD), have to be virtually defect-free in barrier applications for the packaging industry. When aluminum is applied to paper, hygroexpansion and substrate roughness can impair the aluminum coating. Neither effect is easy to detect by microscopy, but both can manifest as an increase in electrical resistance. Here, we quantified the effect of substrate paper hygroexpansion and surface roughness on the effective resistivity ρEFF of aluminum coatings. The sheet resistance of aluminum coated onto four different rough paper surfaces was measured via eddy currents at different relative humidity (0%–95%). The mass of aluminum per unit area was determined by inductively-coupled plasma mass spectrometry (ICP–MS). We calculated ρEFF based on the measured resistance and aluminum mass per unit area, combined with a value for aluminum density from the literature. The substrate roughness was proportional to ρEFF. Relative humidity correlated with the moisture content of the paper substrate according to the Guggenheim, Anderson, and De Boer (GAB) equation, whereas the moisture content showed a linear correlation with hygroexpansion. At relative humidity of up to 50%, hygroexpansion was linearly correlated with the increase in ρEFF, which is related to the mechanical straining and deformation of aluminum. At higher humidity, aluminum started to crack first on rough substrates and later on smooth substrates. The increase in ρEFF was larger on rough substrates. The findings highlight the need for information about substrate roughness, humidity, and hygroexpansion when eddy current measurement results are compared, and will help to ensure that aluminum coatings, applied by PVD, are defect-free.

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Section: Inductively-coupled Plasma-mass Spectrometry (Icp-ms)mentioning

confidence: 99%

Hygroexpansion and Surface Roughness Cause Defects and Increase the Electrical Resistivity of Physical Vapor Deposited Aluminum Coatings on Paper

et al. 2019

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“…The finger-pairs were fabricated by Electron Beam Evaporation (EBE-Temescal FC-2000, Livermore, CA, USA) of a 10 nm-thick Cr film (adhesion layer) and a 100 nm-thick gold layer, using a conventional lift-off photolithographic technique. The thickness of the metallic film (deposited by the evaporation method) [ 13 ] was accurately monitored through quartz crystal micro balance (QCM) measurements. The coating speeds (0.1 Å/s for the Cr adhesion layer and 3 Å/s for the Au layer) and the actual geometrical constraints were considered in real time during each deposition process.…”

Section: Methodsmentioning

confidence: 99%

Significance Testing and Multivariate Analysis of Datasets from Surface Plasmon Resonance and Surface Acoustic Wave Biosensors: Prediction and Assay Validation for Surface Binding of Large Analytes

Puiu

Zamfir

Buiculescu

et al. 2018

Sensors

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In this study, we performed uni- and multivariate data analysis on the extended binding curves of several affinity pairs: immobilized acetylcholinesterase (AChE)/bioconjugates of aflatoxin B1(AFB1) and immobilized anti-AFB1 monoclonal antibody/AFB1-protein carriers. The binding curves were recorded on three mass sensitive cells operating in batch configurations: one commercial surface plasmon resonance (SPR) sensor and two custom-made Love wave surface-acoustic wave (LW-SAW) sensors. We obtained 3D plots depicting the time-evolution of the sensor response as a function of analyte concentration using real-time SPR binding sensograms. These “calibration” surfaces exploited the transient periods of the extended kinetic curves, prior to equilibrium, creating a “fingerprint” for each analyte, in considerably shortened time frames compared to the conventional 2D calibration plots. The custom-made SAW sensors operating in different experimental conditions allowed the detection of AFB1-protein carrier in the nanomolar range. Subsequent statistical significance tests were performed on unpaired data sets to validate the custom-made LW-SAW sensors.

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“…Spot measurements of the coating thickness can be performed by an operator on the line, using portable coating thickness analyzer (CTA) or on randomly selected samples in a laboratory. Usually, such portable CTAs are based on eddy currents, magnetic induction, or beta scattering [6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Industrial X-ray Fluorescence Analyzer for Real-Time Thickness Measurements of Aluminium Coatings on Rolled Steel

Sokolov

Hasikova

Pecerskis³

et al. 2019

Coatings

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Aluminium coatings that are formed by physical vapour deposition (PVD) on rolled steel products are more resistant to atmospheric and seawater corrosion than zinc coatings. We developed a coating thickness analyzer (CTA) with an X-ray fluorescence (XRF) measuring head, that is integrated into the PVD pilot line. In this study, to conduct measurements of elements with atomic numbers less than 20 while avoiding the problem of registration of light elements, the measuring head was integrated into a process vacuum chamber to maintain a vacuum during the measurements. To validate the proposed tool, cold-rolled steel strips of different grades are used as substrates, and aluminium was deposited on the surface via PVD in thicknesses ranging from 1 to 20 g/m2. The thin-film thickness measurements during a pre-acceptance test were found to have a relative accuracy of less than 5% and a relative precision of less than 1% – 2%. The proposed CTA can be readily integrated in the factory’s automatic process control system and the real-time measurements in operating and calibration modes, and the status of all spectrometric equipment (X-ray tube, detector etc.) can be transmitted to the upper-level computer. Thus, the process engineer can properly control the deposition process.

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

Cited by 19 publications

References 106 publications

Hygroexpansion and Surface Roughness Cause Defects and Increase the Electrical Resistivity of Physical Vapor Deposited Aluminum Coatings on Paper

Hygroexpansion and Surface Roughness Cause Defects and Increase the Electrical Resistivity of Physical Vapor Deposited Aluminum Coatings on Paper

Significance Testing and Multivariate Analysis of Datasets from Surface Plasmon Resonance and Surface Acoustic Wave Biosensors: Prediction and Assay Validation for Surface Binding of Large Analytes

Industrial X-ray Fluorescence Analyzer for Real-Time Thickness Measurements of Aluminium Coatings on Rolled Steel

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