1、Designation: F22 02 (Reapproved 2007)F22 13Standard Test Method forHydrophobic Surface Films by the Water-Break Test1This standard is issued under the fixed designation F22; the number immediately following the designation indicates the year of originaladoption or, in the case of revision, the year
2、of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscriptepsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope1.1 This test method covers the detection
3、of the presence of hydrophobic (nonwetting) films on surfaces and the presence ofhydrophobic organic materials in processing ambients.environments. When properly conducted, the test will enable detection ofmolecular layers of hydrophobic organic contaminants. On very rough or porous surfaces, the se
4、nsitivity of the test may besignificantly decreased.1.2 The values stated in SI units are to be regarded as the standard. The inch-pound values given in parentheses are forinformation only.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It i
5、s the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C813 Test Method for Hydrophobic Contamination on Glass by Contact Angle MeasurementD
6、351 Classification for Natural Muscovite Block Mica and Thins Based on Visual QualityD1193 Specification for Reagent WaterD2578 Test Method for Wetting Tension of Polyethylene and Polypropylene FilmsD5946 Test Method for Corona-Treated Polymer Films Using Water Contact Angle MeasurementsD7334 Practi
7、ce for Surface Wettability of Coatings, Substrates and Pigments by Advancing Contact Angle MeasurementD7490 Test Method for Measurement of the Surface Tension of Solid Coatings, Substrates and Pigments using Contact AngleMeasurementsF21 Test Method for Hydrophobic Surface Films by the Atomizer Test3
8、. Terminology3.1 Definitions:3.1.1 contact angle, nthe interior angle that a drop makes between the substrate and a tangent drawn at the intersectionbetween the drop and the substrate as shown in Fig. 1; this is the angle formed by a liquid at the three phase boundary where aliquid, gas (air) and so
9、lid intersect.3.1.2 hydrophilichaving a strong affinity for water, wettable.3.1.2.1 DiscussionHydrophilic surfaces exhibit zero contact angle with water. A sessile drop of water applied to the surface will immediately spreadout to form a film.3.1.3 hydrophobichaving little affinity for water, nonwet
10、table.1 This test method is under the jurisdiction of ASTM Committee E21 on Space Simulation and Applications of Space Technology and is the direct responsibility ofSubcommittee E21.05 on Contamination.Current edition approved April 1, 2007Nov. 1, 2013. Published April 2007November 2013. Originally
11、approved in 1962. Last previous edition approved in 20022007 asF22 02.F22 02 (2007). DOI: 10.1520/F0022-02R07.10.1520/F0022-13.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information,
12、 refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict al
13、l changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-29
14、59. United States13.1.3.1 DiscussionHydrophobic surfaces exhibit contact angles between a sessile drop of water and the surface appreciably greater than zero.3.1.4 sessile dropa drop of liquid sitting on the upper side of a horizontal surface.3.1.5 water-breaka break in the continuity of a film of w
15、ater on a surface on removal from an aqueous bath or on removalof a flowing water source from the surface.4. Summary of Test Method4.1 The water-break test is performed by withdrawing the surface to be tested, in a vertical position, from a container of purifiedwater and observing the behavior of th
16、e water. For large parts, the test surface may be doused with water and the water behaviorobserved on removal of the water source.4.2 The water-break test is performed by withdrawing the surface to be tested, in a vertical position, from a containeroverflowing with water. The interpretation of the t
17、est is based upon the pattern of wetting. interpretation of the test is based uponthe pattern of wetting. Contaminated areas having a surface tension lower than water will cause the water to bead up at that locationor “break” while draining. Most common film contaminants such as oils, silicones, or
18、fluorocarbon greases have surface tensionssignificantly lower than water. In the absence of hydrophobic films, the draining water layer will remain as a film over the surface.In areas where hydrophobic materials are present on the surface, the draining water layer will break up into a discontinuous
19、filmwithin one minute.NOTE 1It is possible to use this test method with liquids other than water. Liquids with different wetting tensions will exhibit different contact angleswith a given surface and therefore different levels of sensitivity to hydrophobic films. This principle has been applied to d
20、evelop differential wettingtension tests such as described in Test Method D2578 using standardized liquids commonly referred to as dyne liquids.5. Significance and Use5.1 The water-break test as described in this test method is rapid, nondestructive, and may be used for control and evaluationof proc
21、esses for the removal of hydrophobic contaminants. This test method is commonly used for in-process verification of theabsence of surface contaminants on metal surfaces that may interfere with subsequent surface treatments such as priming,conversion coating, anodizing, plating, or adhesive bonding5.
22、2 This test method is not quantitative and is typically restricted to applications where a go/no go evaluation of cleanliness willsuffice.5.3 The water-break test as described in this test method is nondestructive and may be used for control and evaluation ofprocesses for the removal of hydrophobic
23、contaminants. The test may test may also be used for the detection and control ofhydrophobic contaminants in processing ambients.environments. For this application, a witness surface free of hydrophobic filmsis exposed to the ambientenvironment and subsequently tested. The sensitivity of this test w
24、ill vary with the level of airbornecontaminant and the duration of exposure of the witness surface.5.4 For quantitative measurement of surface wetting, test methods that measure contact angle of a sessile drop of water or othertest liquid may be used in some applications. Measurement methods based o
25、n contact angle are shown in Test Methods C813,D5946, and D7490; and Practice D7334.5.4.1 Devices for in situ measurement of contact angle are available. These devices are limited to a small measurement surfacearea and may not reflect the cleanliness condition of a larger surface. For larger surface
26、 areas, localized contact angle measurement,or other quantitative inspection, combined with water-break testing may be useful.5.5 For surfaces that cannot be immersed or doused with water, or where such immersion or dousing is impractical,Test MethodF21 may be useful.NOTE 2This test method is not ap
27、propriate where line of sight evaluation is not feasible; or for assembled hardware where there is a risk forentrapment of water in faying surfaces or complex structures where it may not be effectively removed.A = contact angleD = drop of liquidP = specimenT = tangent at specimen surfaceFIG. 1 Conta
28、ct AngleF22 1326. Interferences6.1 Loss of sensitivity may result from either of the following factors:6.1.1 The presence of hydrophilic substances on the surface to be tested, in the test equipment, or in the test materials, or6.1.2 An unusually rough or porous surface condition.6.2 On hot parts or
29、 in elevated temperature conditions, water may evaporate before water-break can be observed.7. Apparatus7.1 Overflow Container, such as a glass beaker.beaker for small parts.7.2 Purified Water Source, final rinse tank or dousing hose and drain, for large parts.7.3 Low Power Microscope, (5 to 50) and
30、 light source for observation of small piece parts.parts (optional).8. Reagents and Materials8.1 Purity of ReagentsReagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that allreagents shall conform to the specifications of the Committee on Analytical Reagen
31、ts of the American Chemical Society,3 wheresuch specifications are available. Other grades may be used, provided it is first ascertained that the reagent is of sufficiently highpurity to permit its use without lessening the accuracy of the determination.8.1 Purity of WaterDeionized or distilled wate
32、r per Specification D1193 Types II, III, or IV is preferred. Water of higher ioniccontent may render the test destructive. The water used must be free of hydrophobic and hydrophilic substances.substances.Whenprocessing large parts in a production environment, the water shall be sampled directly from
33、 the rinse tank or at the exit of thedousing water source prior to water-break test. Hydrophilic contaminants such as trace surfactants present on the rinse tank wallsor dousing hose may contaminate the test water and invalidate the test. Statistical process control may be used to verify thecleanlin
34、ess of the test water in lieu of sampling prior to each water-break test.NOTE 3The freedom Freedom of the water from hydrophobic and hydrophilic contamination may be determined in accordance with Section9Appendix X1.8.2 Acetone. Acetone, reagent grade, A.C.S.38.3 Mica Blanks, preferably 25 by 50 by
35、0.38 mm (1 by 2 by 0.015 in.) or larger, larger.having4minimum ASTM Quality V6as described in Classification D351.8.4 Oleic or Stearic AcidA 0.05 % solution in acetone.9. Calibration and Standardization9.1 Freedom of the test equipment and materials from hydrophobic contamination shall be determined
36、 as described in 10.1 ona mica sheet having both surfaces freshly cleaved. If water-break does not occur within 1 min after withdrawal of the freshlycleaved mica surface from the overflow container, the test equipment and materials shall be considered free of hydrophobiccontamination for this test.9
37、.2 To ensure the freedom of the test equipment and materials from hydrophilic contamination, a mica sheet having bothsurfaces freshly cleaved, from which the solvent from 1 drop (0.05 to 0.10 mL) of a 0.05 % solution of oleic or stearic acid inacetone has been allowed to evaporate shall, when tested
38、, clearly show within 1 min the demarkation between the clean andcontaminated areas.9. Procedure9.1 Testing of SurfacesWithdraw the test surface, in a vertical position, from the container overflowing with water.9.1.1 Immerse the test surface in clean water. This water may be the final rinse of a mu
39、lti-step cleaning or surface treatmentprocess. For very large surfaces, water may be applied to the vertical surface with a hose or gentle spray.9.1.2 Withdraw the test surface, in a vertical position, from the container of water or withdraw the flowing water source.9.1.3 Immediately upon removal fr
40、om the water, or removal of the flowing water source, observe the gravity flow of the waterfrom the test surface for 1 min.9.1.4 Dry the surface of any remaining water on completion of the test. Corrosion-sensitive surfaces should be driedimmediately by a flow of clean, oil-free air or nitrogen. Dry
41、ing may be enhanced by a rinse with isopropyl alcohol prior to dryingwith oil-free air or nitrogen.3 Reagent Chemicals, American Chemical Society Specifications , , American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed bytheAmerican Chemical Society, seeAna
42、lar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and National Formulary,U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.4 Mica meeting quality level V-6 or better per Classification D351 has been found to be acceptable.F22 133NOTE 4T
43、he presence of oil or contaminants in the drying gas or the processing environment may recontaminate the surface and invalidate thewater-break test results.9.2 Testing of AmbientsProcessing EnvironmentsExpose a freshly cleaved mica surface to the ambientsmooth test surface,verified clean and water-b
44、reak-free, to the environment and subsequently continue as described in 11.110.1.Afreshly cleaved micablank may be used as the test surface.NOTE 5Exposure For testing of rinse water, exposure may be by immersion of the micatest surface in the ambientwater or by deposition of a sampleof the ambientwa
45、ter on the micatest surface.10. Interpretation of Results10.1 Surfaces tested as described in 10.19.1 shall be considered free of hydrophobic contaminants by this test method if thedraining water layer remains as a thin continuous film over the surface for 1 min60 s after withdrawal of the surface f
46、rom theoverflow container. immersion container or removal of the dousing water source (see Fig. 2). If hydrophobic contaminants arepresent, as evidenced by formation of a discontinuous water film within 1 min60 s after withdrawal from or of the surface fromthe overflow container, the test fluid, the
47、 length of time necessary for the water-break to occur is a rough indication of the degreeof contamination.10.2 A discontinuous film may appear in the form of localized or general beading of the water, or discontinuous flow of thewater around discrete locations where contaminants are present (see Fi
48、g. 3 and Fig. 4). Significant contamination will be apparentwithin 2 to 15 s.11. Precision and Bias11.1 Precision and bias are intended to be adequate for use as an in-process monitoring method.11.1.1 RepeatabilityRepeatability of this test method requires inspectors that have been trained in the ob
49、servation of surfacesfor water breaks.11.2 Bias:11.2.1 No absolute standard traceable to the National Institute of Standards and Technology is available, therefore the bias ofthis test method cannot be determined at this time.12. Keywords12.1 contact angle; hydrophilic films; organic contamination; surface contaminationcontamination; water breakFIG. 2 Clean aluminum panel showing no water break. Waterdrains in a continuous sheet.F22 134APPENDIXX1. CALIBRATION AND STANDARDIZATIONX1.1 Calibration and StandardizationX1.1.1 Freedom of the test equipment and m
