EN ISO 3868:1994

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Metallische und andere anorganische Schichten - Messung von Schichtdicken - Fizeau-Vielstrahl-Interferenz-Verfahren (ISO 3868:1976)Revetements métalliques et autres revetements non organiques - Mesurage de l'épaisseur - Méthode basée sur le principe de Fizeau d'interférométrie a faisceaux multiples (ISO 3868 :1976)Metallic and other non-organic coatings - Measurement of coating thicknesses - Fizeau multiple-beam interferometry method (ISO 3868:1976)25.220.40Kovinske prevlekeMetallic coatings25.220.20Površinska obdelavaSurface treatment17.040.20Lastnosti površinProperties of surfacesICS:Ta slovenski standard je istoveten z:EN ISO 3868:1994SIST EN ISO 3868:1999en01-oktober-1999SIST EN ISO 3868:1999SLOVENSKI
STANDARD
INTERNATIONAL STANDARD 3868 INTERNATIONAL ORGANIZATION FOR STANDARDIZATION l MEXW(aYHAPOflHAR OPI-AHM3AUM/I n0 CTAHLIAPTM3AUMM *ORGANISATION INTERNATIONALE DE NORMALISATION Metallic and other non-organic coatings - Measurement of coating thicknesses - Fizeau multiple-beam interferometry method Rev&emen ts mtitaliques et autres revetemen ts non organiques - Mesurage de l’epaisseur - M&hode bas6e sur Ie Principe de Fizeau d’in terfkrometrie 2 faisceaux multiples First edition - 1976-11-01 UDC 669.058 : 531.715.1 Ref. No. ISO 3868-1976 (E) Descriptors : coatings, metal coatings, dimensional measurement, thickness, Optical measurement, interferometers. Price based on 4 pages SIST EN ISO 3868:1999

FOREWORD ISO (the International Organization for Standardization) is a worldwide federation of national Standards institutes (ISO Member Bodies). The work of developing International Standards is carried out through ISO Technical Committees. Every Member Body interested in a subject for which a Technical Committee has been set up has the right to be represented on that Committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. Draft International Standards adopted by the Technical Committees are circulated to the Member Bodies for approval before their acceptance as International Standards by the ISO Council. International Standard ISO 3868 was drawn up by Technical Committee ISO/TC 107, Metallic and other non-organic coatings, and was circulated to the Member Bodies in July 1975. lt has been approved by the Member Bodies of the following countries : Bulgaria Italy Czechoslovakia Japan France Mexico Germany New Zealand Hungary Poland India Portugal Israel Romania South Africa, Rep. of Switzerland Turkey U.S.A. U.S.S.R. The Member document : Body of the following country expressed United Kingdom disapproval of the 0 International Organkation for Standardkation, 1976 l Printed in Switzerland SIST EN ISO 3868:1999

INTERNATIONAL STANDARD ISO 3868-1976 (E) Metallic and other non-organic coatings - Measurement of coating thicknesses - Fizeau multiple-beam interferometry method 1 SCOPE AND FIELD OF APPLICATION This International Standard specifies a method for the measurement of the thickness of thin, highly reflective coatings (up to 2 Pm) by the use of Fizeau multiple-beam interferometry. The method described cannot be applied to vitreous enamel coatings. 2 PRINCIPLE By completely dissolving a small area of the coating without attack of its Substrate (or by masking before plating), a step is formed from the surface of the coating to that of its Substrate. The height of this step is measured with a multiple-beam interferometer. A monochromatic light beam is reflected back and forth between the specimen surface and a superimposed trans- parent mirror serving as a planar reference plate, so as to produce a Pattern of interference fringes observed through a low-power microscope. The reference plate is tilted slightly with respect to the surface being inspected, so that the fringe Pattern is a series of parallel lines. A step in the specimen surface Causes a shift in the fringe Pattern. A shift of one full fringe spacing is equivalent to a vertical displace- ment of 1/2 of the wavelength of the monochromatic light. The whole and fractional number of fringe spacings occupied by the fringe shift is determined with an eyepiece micrometer. 3 DEFINITIONS 3.1 filar micrometer eyepiece : A device for observing and measuring an image. lt includes an adjustable lens, a hairline that is moved with a graduated knob, and a Pattern of lines (graticule lines) across the field of view. 3.2 filar units : The graduations on the micrometer control which are proportional to the absolute unit of length. 3.3 Fizeau plate : An optically flat, smooth surface with high reflectivity and low absorption. 3.4 fringe lines : The dark lines caused by interference of light waves. 3.5 hairlines : The part of the filar eyepiece moved by means of the graduated knob to measure fringe line-spacing and offset. 3.6 offset : The displacement of a fringe line which occurs when it encounters a vertical Variation on the surface of a specimen. 3.7 spacing : The distance between fringe lines. 4 EQUIPMENT The instrument employs : a) a beam of monochromatic light; b) optics to direct the light through a specially coated Fizeau plate which Comes into contact with the specimen at a slight angle and forms an air wedge. An interference fringe Pattern is produced in the air wedge and viewed through a microscope equipped with a filar micrometer eyepiece. The spacing and shape of the fringe lines tan be interpreted to determine an extremely accurate contour map of the specimen surface. 5 FACTORS AFFECTING THE MEASURING ACCU- RACY The following factors may affect the accuracy of a coating thickness measurement : 5.1 Reflective overcoat In Order to obtain dark, narrow fringe Iines necessary to achieve an accurate measurement, and in Order to avoid errors due to different Phase shifts, when light reflects over different materials, the test specimen shall be coated with a highly reflective material such as aluminium or silver. If the surfaces at the step are highly reflective and the errors due to Phase shift are known and corrected for, then the reflective layer tan be avoided. SIST EN ISO 3868:1999

ISO 38684976 (E) 5.2 Step form For specimens with a coating thickness of less than 03 Pm special fabrication is not normally necessary. independent estimate of thickness on the basis of prior knowledge, or on measurements by other techniques such as profilometry, white-light i
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