AS-3894.9-2003.pdf
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1、 1 AS 3894.92003 Standards Australia Australian Standard TM Site testing of protective coatings Method 9: Determination of adhesion PREFACE This Standard was prepared by the Australian members of the Joint Standards Australia/Standards New Zealand Committee CH-003, Paints and Related Materials. Afte
2、r consultation with stakeholders in both countries, Standards Australia and Standards New Zealand decided to develop this Standard as an Australian Standard rather than an Australian/New Zealand Standard. FOREWORD The measurement of a coatings ability to adhere or bond to the surface to which it has
3、 been applied and the intercoat adhesion between subsequent layers of previously applied coatings are major factors when determining a maintenance schedule or writing a maintenance specification for a structure. The onsite measurement of adhesion will over a period help to determine the degree of ur
4、gency or programming of a maintenance processes when protecting a structure from atmospheric or other corrosive elements in its own environment. METHOD 1 SCOPE This Standard provides a method for evaluating and testing the adhesion of existing coating systems to their substrate while in their servic
5、e environment. 2 DEFINITIONS For the purpose of this Standard, the definitions in AS 2310 apply. 3 REFERENCED DOCUMENTS The following documents are referred to in this Standard: AS 1580 Paints and related materialsMethods of test 1580.408.4 Method 408.4: Adhesion (cross-cut) 1635 Methods of test for
6、 pressure-sensitive adhesive tape 1635.3.1 Part 3.1: Adhesion strength AS 3894.9 Accessed by UNIVERSITY OF SOUTH AUSTRALIA on 20 May 2008 AS 3894.92003 2 Standards Australia .au AS 3894 Site testing of protective coatings 3894.3 Part 3: Determination of dry film thickness 3894.7 Part 7: Determinatio
7、n of surface temperature AS/NZS 2310 Glossary of paint and painting terms 4530 Coated abrasiveCloth rolls 4 APPLICATION 4.1 General Three methods of assessing the adhesion or bonding of a coating system to its substrate are referred to as Methods A, B and C described in Clauses 5, 6 and 7. Methods A
8、 and B are qualitative and Method C is quantitative. Because Methods A and B are analogous, the reliability of the test results will be confirmed if both methods are conducted and compared at the same time. Because Method C, Pull-off, may take several days for the test to stabilize under field condi
9、tions, it is not recommended that the test be used for routine quality control. All three test methods will damage the coating system. A repair specification should be available to repair the coating if it is to be placed back into service. Because the adhesion, hardness and flexibility of most coat
10、ings will vary with changes in temperature, testing is best performed within the temperature range of 1525C. Should the operating temperature or the temperature at the time of testing be outside this range, the manufacturers advice should be sought. If adhesion fails between coats (inter-coat adhesi
11、on) in a multi-coat system, the adhesion of the coating system to the substrate cannot be determined with reliability. 4.2 Sampling plan This method recommends a number of randomly selected locations to be tested. It is further recommended that either Method A or B be conducted depending on the film
12、 thickness (see Clause 6.1). For structures (a) 10 m2 or less1 test site; (b) greater than 10 m2 and less than 30 m2 2 test sites; (c) greater than 30 m2 and less than 100 m2 3 test sites; and (d) exceeding 100 m23 test sites plus 1 test site for each additional 100 m2. 5 METHOD A KNIFE TEST 5.1 Pri
13、nciple The previously applied coating is cut through to the substrate surface in the manner described and the ease with which the coating can be removed is determined. Accessed by UNIVERSITY OF SOUTH AUSTRALIA on 20 May 2008 3 AS 3894.92003 .au Standards Australia 5.2 Apparatus 5.2.1 Knife blade A s
14、harp edged, freshly honed knife blade having a sharpened point of 45 or less, for example, a scalpel or blade holder containing snap-off disposable blades. NOTE: A knife with a more substantial blade may be required for ultra-high-build coatings and some high-build coatings. 5.2.2 Surface temperatur
15、e thermometer As specified in AS 3894.7. 5.2.3 Straightedge Approximately 100 mm long. 5.2.4 Film thickness gauge As specified in AS 3894.3. 5.3 Test conditions The test should be performed under normal operating conditions with details of the surface temperature and other environmental factors bein
16、g recorded. 5.4 Intersecting cut method The procedure is as follows: (a) Determine the dry film thickness (DFT) of the target test area in accordance with an appropriate method from AS 3894.3. Record the DFT. (b) Hold the blade against the straightedge and at right angles to the coated surface. Incl
17、ine the blade at an angle of 45 in the direction of the cut and using a single stroke, scribe a cut 25 mm long through to the substrate. (c) Make a second cut as in Step (b), intersecting the centre of the first cut to form two 3045 vees. (d) Using the point of the blade, gently try to lift or prise
18、 the coating from the intersection of the vee. Do not apply force to the point of the blade. (e) Assess the adhesion by applying a rating from Table 1 and record the result. TABLE 1 ADHESION RATING OF COATING (INTERSECTING CUT) Rating scale Appearance 0 No removal 1 Slight trace of peeling or remova
19、l at intersection 2 Jagged removal of up to 1.5 mm at intersection 3 Jagged removal of up to 3.0 mm at intersection 4 Coating easily removed in the area up to 15 mm either side of the intersection of the cuts 5 Removal continues greater than 15 mm beyond the cut Accessed by UNIVERSITY OF SOUTH AUSTR
20、ALIA on 20 May 2008 AS 3894.92003 4 Standards Australia .au 5.5 Report The report shall include the following information: (a) Name of testing organization. (b) Date of testing and report number. (c) Identification and description of the test item and its coating system, substrate details and method
21、 of surface preparation of the substrate. (d) Dry film thickness of the coating system and its age. (e) Test Intersecting cut, description of blade and the location of the test. (f) Test conditions including surface temperature. (g) Rating and comments. (h) Reference to this Australian Standard, i.e
22、., AS 3894.9. (i) Any deviations from this test method. 6 METHOD BCROSS-CUT 6.1 Principle The previously applied coating is cut through to the substrate surface in the cross-cut or cross-hatched manner described and the adhesion of the coating system is assessed by applying and removing a piece of p
23、ressure-sensitive tape from the cuts. The area of coating disturbed or disbonded by the tape is determined. The test is suitable for coatings with a dry film thickness in the 50 m125 m range. Tests performed on DFTs outside this range may be unreliable. 6.2 Apparatus 6.2.1 Knife blade or cross-cutte
24、r A sharp edged tool, e.g., a scalpel or blade holder containing snap-off disposable blades. NOTES: 1 One or more passes with a blade may be required for some high-build coatings. 2 Proprietary cross-hatch cutters that comply with this Standard and AS 1580.408.4 should be used. 6.2.2 Surface tempera
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