Metallic coatings - Measurement of coating thickness - Scanning electron microscope method (ISO 9220:1988)

Specifies a method for the measurement of the local thickness of metallic coatings by examination of cross-section with a scanning electron microscope. It is destructive and has an uncertainty of less than 10 % or 0,1 /um, whichever is greater. It can be used for thicknesses up to several millimetres, but it is usually more practical to use a ligth microscope (ISO 1463). Annex a gives the preparation of cross-sections.

Metallische Überzüge - Messung der Schichtdicke - Verfahren mit Rasterelektronenmikroskop (ISO 9220:1988)

Diese Internationale Norm legt ein Verfahren zur Messung der örtlichen Dicke metallischer Überzüge fest, in dem Querschnitte mit einem Rasterelektronenmikroskop (REM) untersucht werden. Es handelt sich um ein zerstörendes Verfahren, das eine Messunsicherheit von weniger als 10 % oder 0,1 micro m hat. Dieses Verfahren kann für Schichtdicken bis zu mehreren Millimetern verwendet werden, es ist jedoch im allgemeinen zweckmässiger, hierfür ein Lichtmikroskop (ISO 1463) anzuwenden, sofern das möglich ist.

Revêtements métalliques - Mesurage de l'épaisseur de revêtement - Méthode au microscope électronique à balayage (ISO 9220:1988)

La présente Norme internationale prescrit une méthode pour le mesurage de l'épaisseur locale des revêtements métalliques par examen de coupes transversales au microscope électronique à balayage. La méthode est destructive et a une incertitude correspondant à la plus grande des deux valeurs 10 % ou 0,1 µm. Elle est utilisable pour des épaisseurs pouvant atteindre plusieurs millimètres, mais il est habituellement plus pratique, si cela est possible, d'utiliser un microscope optique (ISO 1463).

Kovinske prevleke - Merjenje debeline prevleke - Postopek z vrstičnim elektronskim mikroskopom (ISO 9220:1988)

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2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.þQLPMetallische Überzüge - Messung der Schichtdicke - Verfahren mit Rasterelektronenmikroskop (ISO 9220:1988)Revetements métalliques - Mesurage de l'épaisseur de revetement - Méthode au microscope électronique a balayage (ISO 9220:1988)Metallic coatings - Measurement of coating thickness - Scanning electron microscope method (ISO 9220:1988)25.220.40Kovinske prevlekeMetallic coatings17.040.20Lastnosti površinProperties of surfacesICS:Ta slovenski standard je istoveten z:EN ISO 9220:1994SIST EN ISO 9220:1999en01-oktober-1999SIST EN ISO 9220:1999SLOVENSKI

SIST EN ISO 9220:1999
SIST EN ISO 9220:1999
SIST EN ISO 9220:1999
SIST EN ISO 9220:1999
SIST EN ISO 9220:1999

INTERNATIONAL STANDARD INTERNATIONAL ORGANIZATION FOR STANDARDIZATION ORGANISATION INTERNATIONALE DE NORMALISATION MEX)JYHAPOaHAfl OPTAHM3A~Mfl IlO CTAHJJAPTM3A~MM Metallic coatings - Measurement of coating thickness - Scanning electron microscope method Rev& temen ts rnt5 talliques - Mesurage de f%paisseur de revetement - M&bode au microscope &ectronique h bala yage IS0 9220 First edition 1988-10-01 Reference number IS0 9220 : 1988 (E) SIST EN ISO 9220:1999

IS0 9220 : 1988 (E) Foreword IS0 (the International Organization for Standardization) is a worldwide federation of national standards bodies (IS0 member bodies). The work of preparing International Standards is normally carried out through IS0 technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, govern- mental and non-governmental, in liaison with ISO, also take part in the work. IS0 collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Draft International Standards adopted by the technical committees are circulated to the member bodies for approval before their acceptance as International Standards by the IS0 Council. They are approved in accordance with IS0 procedures requiring at least 75 % approval by the member bodies voting. International Standard IS0 9220 was prepared by Technical Committee ISO/TC 107, Metallic and other inorganic coatings. Annex A of this International Standard is for information only. 0 International Organization for Standardization, 1988 Printed in Switzerland SIST EN ISO 9220:1999

INTERNATIONAL STANDARD IS0 9220 : 1988 (E) Metallic coatings - Measurement of coating thickness - Scanning electron microscope method 1 Scope This International Standard specifies a method for the measurement of the local thickness of metallic coatings by examination of cross-sections with a scanning electron micro- scope (SEM). It is destructive and has an uncertainty of less than 10 96 or 0,l pm, whichever is greater. It can be used for thicknesses up to several millimetres, but it is usually more practical to use a light microscope (IS0 1463) when applicable. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the standards listed below. Members of IEC and IS0 maintain registers of currently valid International Standards. I SO 1463 : 1982, Metallic and oxide coatings - Measurement of coating thickness - Microscopical method. IS0 2064 : 1980, Metallic and other non-organic coatings - Definitions and conventions concerning the measurement of thickness. 3 Definition For the purposes of this International Standard, the following definition applies. local thickness: The mean of the thickness measurements, of which a specified number is made within a reference area. (See IS0 2064.) 4 Principle A test specimen is cut, ground, and polished from a cross- section of the coating for metallographic examination by a scanning electron microscope. The measurement is made on a conventional micrograph or on a photograph of the video waveform signal for a single scan across the coating. 5 Instrumentation 5.1 Scanning electron microscope (SEM) The SEM shall have a resolution capability of 50 nm or better. Suitable instruments are available commercially. 5.2 SEM stage micrometer A stage micrometer or graticule is required for calibration of the magnification of the SEM. The stage micrometer or graticule shall have an uncertainty of less than 5 % for the magnification employed. Suitable stage micrometers or graticules are available commercially. 6 Factors influencing the measurement results The following factors may affect the accuracy of a measure- ment of coating thickness. 6.1 Surface roughness If the coating or its substrate is rough relative to the coating thickness, one or both of the interfaces bounding the coating cross-section may be too irregular to permit accurate measure- ment of the average thickness in the field of view. 6.2 Taper of cross-section If the plane of the cross-section is not perpendicular to the plane of the coating, the measured thickness will be greater than the true thickness. For example, an inclination of loo to the perpendicular will contribute a 1,5 % error. 6.3 Specimen tilt Any tilt of the specimen (plane of cross-section) with respect to the SEM beam may result in an inaccurate measurement. NOTE - If the tilt of the test specimen is different from that used for calibration, inaccuracies may result. 6.4 Coating deformation Detrimental deformation of the coating can be caused by excessive temperature or pressure during the mounting and preparation of cross-sections of soft coatings or coatings that melt at low temperatures, and by excessive abrasion of brittle materials during preparation of cross-sections. 1 SIST EN ISO 9220:1999

Is0 9220 : 1988 (El 6.5 Rounding of edges of the coating If the edge of the coating cross-section is rounded, i.e. if the coating cross-section is not completely flat up to its edges, the observed thickness may differ from the true thickness. Edge rounding can be caused by improper mounting, grinding, polishing, or etching (see 6.6 and clause A.l). 6.6 Overplating Overplating of the test specimen serves to protect the coating edges during preparation of cross-sections and thus to prevent an inaccurate measurement. Removal of the coating material during surface preparation for overplating can cause a low thickness measurement. 6.7 Etching Optimum etching will produce a clearly defined and narrow dark line at the interface between the two metals. A wide or poorly defined line can result in an inaccurate meaurement. 6.8 Smearing Polishing may leave smeared metal that obscures the true boundary between two metals and results in an inaccurate measurement. This may occur with soft metals like lead, indium, and gold. To help identify whether or not there is smearing, repeat the polishing, etching, and measurement several times. Any significant variation in readings is an indica- tion of possible smearing. 6.9 Poor contrast The visual contrast between metals in an SEM is poor when their atomic numbers are close together. For example, bright and semi-bright nickel layers may not be discriminable unless their common boundary can be brought out sufficiently by appropriate etching and SEM techniques. For some metal com- binations, energy dispersive X-ray techniques (see A.3.5) or backscatter images (see A.3.6) can be helpful. 6.10 Magnification For a given coating thickness, measurement errors tend to increase with decreasing magnification. If practical, the magnification should be chosen so that the field of view is between 1,5 and 3 times the coating thickness. The magnification readout of an SEM often differs from the actual magnification by more than the 5 % often quoted and, for some instruments, the magnification has been found to vary by 25 % across the field. Magnification errors are minimized by appropriate use of an SEM stage micrometer. 6.11 Uniformity of magnification Because the magnification may not be uniform over the entire field, errors can occur if both the calibration and the measure- ment are not made over the same portion of the field. These errors can be very significant. 2 6.12 Stability of magnification 6.12.1 The magnification of an SEM may drift with time. This effect is minimized by mounting the stage micrometer and test specimen side by side on the SEM stage so as to keep the transfer time short. 6.12.2 A change in magnification can occur when adjustments are made with the focusing and other SEM elec- tronic controls; for example the scan rotation, operating voltage and contrast controls. Such a change is prevented by not using the focus controls or other SEM electronic controls after photographing the stage micrometer scale except to focus using the x, y and z controls of the stage. Appropriate manipulation of the x, y and z controls will bring the specimen surface to the focal point of the SEM beam. 6.13 Stability of micrographs Dimensional changes of micrographs can take place with time and with temperature and humidity changes. If the calibration micrograph of the stage micrometer scale and the micrograph of the test specimen are kept together and time is allowed for stabilization of the photographic paper, errors from this source will be minimized. The use of resin-coated paper is advised. 7 Preparation of cross-sections Prepare the test specimen so that a) the cross-section is perpendicular to the plane of the coating ; b) the surface is flat and the entire width of the coating image is simultaneously in focus at the magnification to be used for the measurement; c) all material deformed by cutting or cross-sectioning is removed ; d) the boundaries of the coatin


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