Coating durability, testing

Once the durability testing of the fuel cells is finalized, the internal components are then characterized. For diffusion layers, some of these characterization techniques include SEM to visualize surface changes, porosimetry measurements to analyze any changes in porosity within the DL and MPL, IGC (inverse gas chromatography) to identify relative humidity effects on the hydrophobic properties of the DLs, contact angle measurements to observe any changes in the hydrophobic/hydrophilic coatings of the DL, etc. [254,255]. 

Ryntz, R. A. Plastics and Coatings Durability, Stabilization Testing, Hansen Gardner 2001. 

We speculate that contact of this surface with the atmosphere prior to coating with test polymer or mirror backing paint could be related to mirror durability. Regardless, improved polymer additives and particularly mirror backings must be found before durable polymer/mirror assemblies can be developed. The backings must be flexible, Impermeable and light-stable, and they must not contain solvents that will swell the polymer or disrupt the polymer/mlrror Interface. Thus, these backings may have to be polymer specific. 

The direct correlation observed in this study between gloss loss rates and photoinitiation rates suggests that the nitroxide doping technique could provide a rapid test for the evaluation of coating durability. Measurements of nitroxide decay kinetics to determine coating photoinitiation rates can be made at near ambient exposure conditions in a few days (compared to years for... 

Schulz, U.. and Trubiroha. P. (1996), Predicting water spot and acid etch resistance of dear-coats by artificial weathering Acid dew and fog test. Durability Testing of Sonmetallie. Materials. ASTM STP 1294 (Robert J. Herling. ed.), American Society for Testing and Materials. 

Figure 7.18 ORR curves on 20-wl% Pl/Nb02 and 20-wt% Pl/Ti407 nanofiber catalysts coated on a glassy carbon electrode (0.196 cm ), measured in 02-saturated 0.1 M HCIO4 solution (30 C). (A) Pl/NbOa, before durability test of cyclic voltammetric cycling for 2000 cycles in N2-saturated 0.1 M HCIO4 solution, (B) Pt/Nb02, after durability test, (C) Pt/Ti40y, before durability test, (D) Pt/Ti4 O7, after durability test. Potential scan rate 5 mV s . Reprinted with...

K. Hardcastle and N. D. Searle, in R. A. Ryntz, ed.. Plastics and Coatings, Durability, Stabilization, Testing, Hanser Gardner, Cincinnati, Oh, 2001, Chapter 9. 

Fig. 20.20 Examples of durability test results over repeated worst-case regenerations with zeolite SCR catalyst coated high porosity aluminum titanate filter [51]...

FIGURE 10.18 Fluoride emissions of CCMs during accelerated durability testing. (Repr mtediromlnt.J.Hydrogen Energy, 35, S. Mu. Accelerated durability tests of catalyst layers with various pore volumes for catalyst coated membranes applied in PEM fuel cells, 2872-2876, Copyright (2010), with permission from Elsevier.)... 

S. Mu. 2010. Accelerated durability tests of catalyst layers with various pore volumes for catalyst coated membranes apphed in PEM fuel cells. 35 2872-2876. 

Zhang et al. [58] developed superhydrophobic aluminum alloys by one-step spray coating of an alcohol solution consisting of hydrophobic silica nanoparticles (15-40 nm) and methyl silicate precursor on etched aluminum alloy with pitted morphology. The as-sprayed metal surface showed APCA of 155° and ROA of 4°. In their study they used many different mechanical durability tests that we will describe in the next section and... 

Cocuzzi DA, Pilcher GR (2013) Ten-year exterior durability test results compared to various accelerated weathering devices joint study between ASTM international and national coil coaters association. Prog Org Coat 76(6) 979-984... 

Hardcastle HK, Searle ND (2001) Weathering test methods. In Ryntz R (ed) Plastics and coatings durability, stabilization, testing. Hanser, Munich, pp 189-240, Chapter 9... 

Alternative ex situ accelerated tests have been reported. Aoki et al. (2005,2006) developed a novel ex situ method for membrane durability tests, in which mixed gases of Hj and air were supplied at given ratios to a water suspension of a Pt/C catalyst coated with Nafion . This method has an advantage that it can simulate the atmospheres on the anode side (H rich) and the cathode side (O rich) by changing... 

Table 1 Surface energies (by the Owens-Wendt method) of two different SIGRACET gas diffusion layer (GDL) types before and after accelerated durability testing (different catalyst-coated membranes were used in the cells)...

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