Permeation rate measurements by electrical analysis of calcium corrosion

Paetzold, Ralph; Winnacker, A.; Henseler, Debora; Cesari, Valentina; Heuser, Karsten

doi:10.1063/1.1626015

Cited by 222 publications

(177 citation statements)

References 8 publications

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“…The principle of electrical Ca test is derived from the electrical transformation of Ca corrosion [36]. Chemical reactions of Ca with water vapor and oxygen make Ca become calcium oxide or calcium hydroxide [36]. During the reactions, Ca simultaneously transforms from an opaque and conductive state to a transparent and insulating one, so WVTR value can be determined through such reactions.…”

Section: Wvtr Testmentioning

confidence: 99%

“…A sampling rate of once every 10 min was set to record the electrical current data. The principle of electrical Ca test is derived from the electrical transformation of Ca corrosion [36]. Chemical reactions of Ca with water vapor and oxygen make Ca become calcium oxide or calcium hydroxide [36].…”

Section: Wvtr Testmentioning

confidence: 99%

“…A 250-nm-thick Ca sensor of an area of 10 mm × 10 mm is used to measure the WVTR value. The WVTR value can be determined from the slope of the conductance curve versus time [36]. The equation used to determine WVTR value is expressed as [10]:…”

Section: Wvtr Testmentioning

confidence: 99%

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Effects of Long-Term Static Bending Deformation on a Barrier Thin Film for Flexible Organic Optoelectronic Devices

Tran

Lin

et al. 2018

Coatings

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Abstract:The objective of this study is to investigate the effect of long-term static bending on the encapsulation properties of a commercial barrier thin film for flexible optoelectronic devices. Encapsulation properties of the barrier film are evaluated under long-term static bending at various radii of curvature. Experimental results reveal that no significantly detrimental effect on the water vapor transmission rate (WVTR) at 40 • C and 90% RH is found for compressive bending up to 1000 h and for tensile bending up to 100 h with a radius of curvature of 5 mm or larger. However, WVTR of the barrier thin film is significantly increased and cracks are found in the barrier film when subjected to tensile bending of a radius of 10 mm or 5 mm for 1000 h. The expected WVTR of the given barrier thin film is numerically computed using a three-dimensional (3D) finite element model. Numerical results indicate that, with the presence of cracks in the barrier thin film, the WVTR increases for an apparent increase in moisture entrances. The WVTR calculated by the 3D cracking model concurs with the experimental results.

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Section: Wvtr Testmentioning

confidence: 99%

Section: Wvtr Testmentioning

confidence: 99%

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Effects of Long-Term Static Bending Deformation on a Barrier Thin Film for Flexible Organic Optoelectronic Devices

Tran

Lin

et al. 2018

Coatings

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“…Several approaches can be used for the measurement of water vapor permeation through films, including calcium corrosion tests, coulometric electrochemical devices, radioactive methods, mass spectrometry, and infrared light spectroscopy. [4][5][6][7][8][9][10][11][12][13][14] Two isostatic carrier gas systems are commercially available for the measurement of moisture permeation: the Aquatran® devices from MOCON®, Inc., with a detection limit of (5 × 10 5 ± 5 × 10 5 ) g m 2 d 1 and the HiBarSens® from SEMPA Systems GmbH, with a detection limit of 1 × 10 6 g m 2 d 1 . 15,16 The measurement of ultra-high barrier materials is challenging because of the long conditioning and measurement times.…”

Section: Introductionmentioning

confidence: 99%

A systematic approach for the accurate and rapid measurement of water vapor transmission through ultra-high barrier films

Kiese

Kücükpinar

Reinelt

et al. 2017

Review of Scientific Instruments

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Flexible organic electronic devices are often protected from degradation by encapsulation in multilayered films with very high barrier properties against moisture and oxygen. However, metrology must be improved to detect such low quantities of permeants. We therefore developed a modified ultra-low permeation measurement device based on a constant-flow carrier-gas system to measure both the transient and stationary water vapor permeation through high-performance barrier films. The accumulation of permeated water vapor before its transport to the detector allows the measurement of very low water vapor transmission rates (WVTRs) down to 2 × 10−5 g m−2 d−1. The measurement cells are stored in a temperature-controlled chamber, allowing WVTR measurements within the temperature range 23–80 °C. Differences in relative humidity can be controlled within the range 15%–90%. The WVTR values determined using the novel measurement device agree with those measured using a commercially available carrier-gas device from MOCON®. Depending on the structure and quality of the barrier film, it may take a long time for the WVTR to reach a steady-state value. However, by using a combination of the time-dependent measurement and the finite element method, we were able to estimate the steady-state WVTR accurately with significantly shorter measurement times

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“…The measured WVTR is linear to the derivative of the current through the Ca sensor over time. 18 Therefore, a stronger current loss leads to an overestimated WVTR. The effect is also observed for samples with Al contacts deposited after the Ca sensor and for Ag contacts, as we display in Figure S2.…”

mentioning

confidence: 99%

Note: Inhibiting bottleneck corrosion in electrical calcium tests for ultra-barrier measurements

Nehm

Müller‐Meskamp

Klumbies

et al. 2015

Review of Scientific Instruments

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A major failure mechanism is identified in electrical calcium corrosion tests for quality assessment of high-end application moisture barriers. Accelerated calcium corrosion is found at the calcium/electrode junction, leading to an electrical bottleneck. This causes test failure not related to overall calcium loss. The likely cause is a difference in electrochemical potential between the aluminum electrodes and the calcium sensor, resulting in a corrosion element. As a solution, a thin, full-area copper layer is introduced below the calcium, shifting the corrosion element to the calcium/copper junction and inhibiting bottleneck degradation. Using the copper layer improves the level of sensitivity for the water vapor transmission rate (WVTR) by over one order of magnitude. Thin-film encapsulated samples with 20 nm of atomic layer deposited alumina barriers this way exhibit WVTRs of 6 × 10−5 g(H2O)/m2/d at 38 °C, 90% relative humidity.

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Permeation rate measurements by electrical analysis of calcium corrosion

Cited by 222 publications

References 8 publications

Effects of Long-Term Static Bending Deformation on a Barrier Thin Film for Flexible Organic Optoelectronic Devices

Effects of Long-Term Static Bending Deformation on a Barrier Thin Film for Flexible Organic Optoelectronic Devices

A systematic approach for the accurate and rapid measurement of water vapor transmission through ultra-high barrier films

Note: Inhibiting bottleneck corrosion in electrical calcium tests for ultra-barrier measurements

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