1、 STD-AECMA PREN 2781-ENGL 1777 LOL231L 001205Li 187 W Edition approved for publication 1997-03-28 AECMA STANDARD NORME AECMA AECMA NORM The equivalent versions in French and German languages C7 Chairman can be supplied by B.N.A.E. - Technopolis 54 - 199, rue Jean-Jacques Rousseau Mr Wright 921 38 IC
2、CY - LES - MOULINEAUX CEDEX - FRANCE prEN 2781 March 1997 PUBLISHED BY THE EUROPEAN ASSOCIATION OF AEROSPACE INDUSTRIES (AECMA) Gulledelle 94 - 6-1 200 BRUXELLES - Tel. (32) 2 775 81 10 - Fax. (32) 2 775 81 11 ICs : 49.025.50 Descriptors : Aircraft industry, adhesives, tests, determination, thicknes
3、s, microscopic analysis, gravimetric methods, eddy current tests ENGLISH VERSION Aerospace series Non-metallic materials Structural adhesives Test methods Determination of the primer thickness Srie arospatiale Luft- und Raumfahrt Matriaux non-mtalliques Nichtmetallische Werkstoffe Adhsifs structurau
4、x Strukturelle Klebstoffe Mthodes dessai Prf verfahren Dtermination de lpaisseur de primaire Bestimmung der Haftgrundmittei-Schichtdicke This “Aerospace series“ Standard has been drawn up under the responsibility of AECMA (The European Association of Aerospace Industries). It is published on yellow
5、paper in three equivalent versions (English, French, German). It will be submitted as a draft European Standard to CEN (European Committee for Standardization) for formal vote. STD-AECMA PREN 27BL-ENGL 1997 U 30323LL 0032055 015 W Page 3 prEN 2781 : 1997 1 Scope This standard defines the test method
6、s for the determination of the primer thickness for structural ad hesives. 2 Normative references This European Standard incorporates by dated or undated reference provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are
7、listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies. IS0 2064 Metallic and ot
8、her non-organic coatings - Definitions and conventions concerning the measurement of the thickness IS0 2360 Non-conductive coatings on non-magnetic basis metals - Measurement of coating thickness - Eddy current method IS0 3543 Metallic and non-metallic coatings - Measurement of thickness - Beta back
9、-scatter method 3 Application of methods Method A : Microscopic measurement : This destructive method is of general use. It is also used to determine reference values for the non-destructive methods. Method B : Gravimetric determination : This non-destructive method is particularly suitable for dete
10、rmination of the primer thickness on test panels. Method C : Eddy current method : This non-destructive method is used for the measurement of the thickness of non-conductive primers on non-ferromagnetic metallic components. For special applications (e.g. automated production), other methods may be s
11、uitable (e.g. the beta backscatter method to IS0 3543). 4 Values for measurement uncertainty - Method A : f 0,8 pm - Method B : f 1 pm - Method C : k 1,5 pm Previous page is blank Page 4 STD-AECMA PREN 2781-ENGL 1977 1012311 00L205b T51 9 prEN 2781 : 1997 5 Method A 5.1 Principle The primer thicknes
12、s is measured on a cross section by means of an optical microscope. 5.2 Apparatus - Basic metallographic equipment for the preparation of microscopic sections. - Optical microscope capable of a magnification of at least 500 times, fitted with an ocular micrometer. 5.3 Test pieces They shall be : - c
13、ut in the direction from the primer to the base material and perpendicularly to the coating surface ; - embedded in a synthetic resin compound according to a procedure adapted to the material avoiding any reaction with the primer and ensuring a suffient contrast to it ; - ground and polished until a
14、ny distortion or damage to the primer due to sampling has been eliminated. The direction of grinding shall be from the primer to the base material. 5.4 Measurement The thickness shall be measured with a magnification of at least 500 times by means of an optical microscope using incident light, the c
15、ross section surface being perpendicular to the optical axis. The ocular micrometer shall be calibrated before measurement. The calibration factor shall be recorded. Five measurements shall be made at various points of the cross section. 5.5 Assessment The primer thickness corresponds to the arithme
16、tical mean of the five measurements. 5.6 Test report It shall include the following : - designation of the method : EN 2781A ; - designation of the primer ; - identification of the ;est pieces, .e. number and position on the component ; - position of the five measurement points ; - calibration facto
17、r of the ocular micrometer ; - thickness in micrometers (individual values and the mean value) ; - deviations from this standard. STD*AECMA PREN 2781-ENGL 1997 LOL231L 0012057 994 Page 5 prEN 2781 : 1997 6 Method B 6.1 Principle Determination of the average thickness based on the ratio : mass per un
18、it area/density of the primer 6.2 Apparatus Balance with a sufficient accuracy to meet the requirements of 6.3. 6.3 Measurements The coating surface of the test panel shall be measured to 1 mm2. The mass of the test panel shall be determined to 0,001 g before applying the primer and immediately afte
19、r curing. 6.4 Calculation of thickness The average thickness is calculated as follows : where : S G Go F Y is the average primer thickness, in micrometres ; ic the mass of test panel with cured primer, in grams ; is the mass of test panel before application of primer, in grams ; is the coating surfa
20、ce, in square millimetres ; is the density of cured primer, in grams per cubic centimetre. 6.5 Test report It shall include the following : - designation of the method : EN 27818 ; - designation of primer ; - density of cured primer ; - identification of the test panel ; - calculated average primer
21、thickness ; - deviations from this standard. STD=AECMA PREN 2781-ENGL 1777 = 1012311 0012058 824 Page 6 prEN 2781 : 1997 7 Method C 7.1 Principle See IS0 2360. 7.2 Definitions See IS0 2360 and IS0 2064. 7.3 Apparatus See IS0 2360. 7.4 Factors affecting the measurement See IS0 2360. 7.5 Adjustment Se
22、e IS0 2360. 7.6 Determining the primer thickness See IS0 2360. 7.7 Assessment For every reference area, the local primer thickness is the arithmetical mean of three individual measurements. The thickness on the significant surface of the measured object is the arithmetical mean of local thicknesses.
23、 7.8 Test report It shall include the following : - designation of the method : EN 2781C ; - designation of primer ; - type and designation of the measured object ; - measurement equipment or installations ; - test conditions ; - type of adjustment, and type of reference test piece ; - position of the significant surfaces ; - position and number of the selected reference areas ; - individual values of the thickness measured on the reference areas, local thicknesses ; - calculated mean value for the significant surface ; - deviations from this standard.
