Test, film penetration

The retardation of the migration of silicone oligomers from the silicone tubing after being coated indicates that the plasma polymer coating applied to the tube substrate is in a form of continuous film with barrier characteristics instead of some other physical forms (e.g., powder). Direct evidence of this aspect can also be seen from the fact that all test specimens prepared had passed the dye penetration test. 

Figure Bl, Rough sketch of film penetration test procedure as described...

Put 2 cc of the test fluid on the film and immediately place the bar on the film, (Do not drop the bar onto the film.) The clamp must be such that the bar is guided vertically, but not impeded. Determine the time required for the bar to penetrate the film. Duplicate trials should be made. Blow test jar free of solvent between trials. 

To make Pick s law tractable for engineering calculations, several theories, or models, have been discussed. Their application usually introduces some empiricism, since distance of diffusion and extent of interfacial area are usually indeterminate. For most calculations, the time-tested film model is appropriate, not because it represents with validity the physical situation, but rather because it is supported by a wealth of experience as well as the ready availability of data, particularly molecular diffusion coefficients. The penetration and surface-renewal models have specialized applications and also depend on empirically derived parameters. 

Both CAP-482-0.5 and CAP-504-0.2 form films that have excellent resistance to penetration by oils and grease. Overprints of these unmodified film formers were applied to paper at 0.1-mil dry film thickness and allowed to dry overnight. Penetration test materials containing a red dye (corn oil, castor oil, hot lard, mineral oil, peanut oil, and water) were placed on the overprints and allowed to remain in contact for 24 h. None of the test materials stained the... 

Arco microknife Instrument designed for testing scratch hardness and adhesion of coatings. A diamond point is weighted until it can penetrate a film to the metal substrate in two retracing steps. The weight necessary to achieve this cutting force for films of standard thickness is a measure of hardness. 

The Kit Test (T-559 pm-96) can be used to measure oU repeUency when there is no physical barrier to oU penetration such as that provided by a film, foU, or waterproof coating (71). Another measure of oU repeUency is the Turpentine Test (T-454 om-89) (71). If a physical barrier is present, tests that measure the weight of oU pick-up or show-through under conditions that simulate the end use are appropriate. 

Using dilatometry in parallel with cyclic voltammetry (CV) measurements in lmolL 1 LiC104 EC-l,2-dimethoxy-ethane (DME), Besenhard et al. [87] found that over the voltage range of about 0.8-0.3 V (vs. Li/Li+), the HOPG crystal expands by up to 150 percent. Some of this expansion seems to be reversible, as up to 50 percent contraction due to partial deintercalation of solvated lithium cations was observed on the return step of the CV. It was concluded [87] that film formation occurs via chemical reduction of a solvated graphite intercalation compound (GIC) and that the permselective film (SEI) in fact penetrates into the bulk of the HOPG. It is important to repeat the tests conducted by Besenhard et al. [87] in other EC-based electrolytes in order to determine the severity of this phenomenon. 

FTR is an effective method for film thickness measurement in mixed lubrication. If the strength of incident light is properly adjusted, the resolution of film thickness by the FTR method can be limited within 5 nm. Theoretically, if the typical height of the surface asperities is less than the penetrating depth, the FTR method can be successfully used. In the tests, it is found that if Ra is greater than 0.15 /rm, a con-... 

Analysis of Table II shows discrepancies in the hardness and stress behavior of a-C(N) H films. Although all the works reported a clear stress reduction upon nitrogen incorporation, the hardness sometimes is quoted as almost constant, or on the other hand clearly decreasing. In addition to the possible effect of different deposition methods and conditions, it can be easily seen that the differences in hardness testing methods are the major source for discrepancies. Constant hardness behavior is only reported with the use microindentation methods, like Vickers and Knoop microhardness. On the other hand, the use of low-load nanoindentation methods always led to a nitrogen-induced decrease in hardness. This is basically the consequence of two factors. The first one is the higher penetration... 

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