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1、BS ISO 26423:2009 ICS 81.060.30 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW BRITISH STANDARD Fine ceramics (advanced ceramics, advanced technical ceramics) Determination of coating thickness by crater-grinding method Licensed CopyChinese University of Hong Kong, 11/04/2009
2、 08:51, Uncontrolled Copy, (c) BSI This British Standard was published under the authority of the Standards Policy and Strategy Committee on 28 February 2009 BSI 2009 ISBN 978 0 580 58969 0 Amendments/corrigenda issued since publication DateComments BS ISO 26423:2009 National foreword This British S
3、tandard is the UK implementation of ISO 26423:2009. The UK participation in its preparation was entrusted to Technical Committee RPI/13, Advanced technical ceramics. A list of organizations represented on this committee can be obtained on request to its secretary. This publication does not purport t
4、o include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard cannot confer immunity from legal obligations. Licensed CopyChinese University of Hong Kong, 11/04/2009 08:51, Uncontrolled Copy, (c) BSI BS ISO 26423:2009 Refe
5、rence number ISO 26423:2009(E) ISO 2009 INTERNATIONAL STANDARD ISO 26423 First edition 2009-01-15 Fine ceramics (advanced ceramics, advanced technical ceramics) Determination of coating thickness by crater-grinding method Cramiques techniques Dtermination de lpaisseur de revtement par la mthode de m
6、eulage de cratre Licensed CopyChinese University of Hong Kong, 11/04/2009 08:51, Uncontrolled Copy, (c) BSI BS ISO 26423:2009 ISO 26423:2009(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobes licensing policy, this file may be printed or viewed but shall not be
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9、r bodies. In the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below. COPYRIGHT PROTECTED DOCUMENT ISO 2009 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by
10、 any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISOs member body in the country of the requester. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-ma
11、il copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2009 All rights reserved Licensed CopyChinese University of Hong Kong, 11/04/2009 08:51, Uncontrolled Copy, (c) BSI BS ISO 26423:2009 ISO 26423:2009(E) ISO 2009 All rights reserved iii Contents Page Foreword iv 1 Scope . 1 2 Normati
12、ve references. 1 3 Symbols. 1 4 Principle. 3 5 Sampling 3 6 Test procedure 3 6.1 General. 3 6.2 Preparation for the test 4 6.3 Test parameters 4 6.4 Example of test parameters. 5 7 Microscopic examination and measurement. 5 7.1 Examination. 5 7.2 Measurement. 5 8 Calculations. 6 9 Uncertainty and so
13、urces of error 7 10 Test report . 7 Annex A (informative) Errors associated with using different formulae for calculating film thickness . 9 Annex B (informative) Estimating measurement uncertainty and errors. 12 Bibliography. 15 Licensed CopyChinese University of Hong Kong, 11/04/2009 08:51, Uncont
14、rolled Copy, (c) BSI BS ISO 26423:2009 ISO 26423:2009(E) iv ISO 2009 All rights reserved Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out
15、 through ISO 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, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO col
16、laborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International S
17、tandards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements
18、 of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 26423 was prepared by Technical Committee ISO/TC 206, Fine ceramics. Licensed CopyChinese University of Hong Kong, 11/04/2009 08:51, Uncontrolled Copy, (c) BSI
19、BS ISO 26423:2009 INTERNATIONAL STANDARD ISO 26423:2009(E) ISO 2009 All rights reserved 1 Fine ceramics (advanced ceramics, advanced technical ceramics) Determination of coating thickness by crater- grinding method 1 Scope This International Standard specifies a method for the determination of the t
20、hickness of ceramic coatings by a crater-grinding method, which includes the grinding of a spherical cavity and subsequent microscopic examination of the crater. Because of the uncertainty introduced into the measurement of crater dimensions, the test is not suitable for use where the surface roughn
21、ess of the coating and/or substrate exceeds 20 % of the coating thickness. NOTE An alternative method for measurement of thickness, using a contact probe profilometer, is given in ISO 18452. 2 Normative references The following referenced documents are indispensable for the application of this docum
22、ent. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 3290-1, Rolling bearings Balls Part 1: Steel balls ISO/IEC 17025:2005, General requirements for the competence of testing and calib
23、ration laboratories 3 Symbols For the purpose of this document, the following symbols apply. D best estimate of the outer diameter of the crater, at the surface of the coating, in micrometres (see Figure 1); d best estimate of the inner diameter of the crater, defined by the bottom of the coating la
24、yer, in micrometres (see Figure 1); h thickness of the coating, in micrometres (see Figure 1); m subscript indicating mean value (Dm, dm, Xm, Ym). rb radius of the ball, in micrometres (see Figure 1); rs radius of curvature of specimen; lT total penetration depth of the ball, in micrometres (see Fig
25、ure 1); lt penetration depth of the ball in the substrate, in micrometres (see Figure 1); Licensed CopyChinese University of Hong Kong, 11/04/2009 08:51, Uncontrolled Copy, (c) BSI BS ISO 26423:2009 ISO 26423:2009(E) 2 ISO 2009 All rights reserved X distance, on a coplanar projection of the two crat
26、ers, between the periphery of the outer crater and a diametrically equivalent point on the same side of the inner crater, in micrometres (see Figure 1); Y distance, on a coplanar projection of the two craters, between the periphery of the outer crater and a diametrically equivalent point on the oppo
27、site side of the inner crater, in micrometres (see Figure 1). Key 1 coating 2 substrate Figure 1 Principal dimensions used in the test method Licensed CopyChinese University of Hong Kong, 11/04/2009 08:51, Uncontrolled Copy, (c) BSI BS ISO 26423:2009 ISO 26423:2009(E) ISO 2009 All rights reserved 3
28、4 Principle Coating thickness often plays a major role in the performance of coated tools and machine parts. Many different techniques have been developed for assessing the coating thickness. Among these, the crater- grinding method and the step height method (see ISO 18452) are easy to perform and
29、applicable to most coated systems. The method is simple and straightforward. A crater is ground into the coated part by means of a rotating ball wetted by an abrasive slurry. The thickness of the coating is derived from the ball and crater dimensional characteristics. Contrast between the different
30、materials constituting the coating and substrate is a prerequisite for the method, to enable detection of the interface between the coating and the surface. Test specimens should be either flat or cylindrical. Flatness can be considered as sufficient if the local specimen radius of curvature, rs, sa
31、tisfies the relation rs 100 rb (for error u 1 %). 5 Sampling A representative test specimen of the product under test shall be used. Test pieces shall be coated original items or, where this is not possible, items made in the same way as the batch to be tested. For large parts, separate manufacturin
32、g of the test piece may be necessary. 6 Test procedure 6.1 General A ball wetted by an abrasive slurry is rotated against the surface of the test piece. A spherical wear crater is produced, and the test is finished when the depth of penetration of the spherical crater is greater than the coating thi
33、ckness. The coating thickness is then derived from the dimensions of the wear scars (full crater and substrate crater diameters) and the ball diameter. Different test rig set-ups may be used. The ball can be rotated freely on a drive shaft, whereby its mass is used to produce the contact load, or it
34、 may be clamped in the drive axis while the specimen is loaded by means of a lever system. A typical arrangement is shown in Figure 2. Alternatively, a wheel instead of a ball may be used, in which case the sample shall also be rotated (this is the same principle as used with dimple grinders for the
35、 preparation of TEM specimens). Different abrasives (e.g. diamond, alumina, silica) can be used, and commercially available suspensions based on alcohol, oil or water may be applied. The abrasive slurry may be smeared onto the ball surface prior to testing, but more repeatable measurements are achie
36、ved when the abrasive slurry is drip-fed into the contact region, e.g. by peristaltic pumping of a stirred suspension. The grain size of the abrasive shall be small enough to avoid roughening of the crater borders. For example, 1 m diamond paste suspended in ethanol is often used. Licensed CopyChine
37、se University of Hong Kong, 11/04/2009 08:51, Uncontrolled Copy, (c) BSI BS ISO 26423:2009 ISO 26423:2009(E) 4 ISO 2009 All rights reserved Key 1 ball 2 specimen Other orientations may also be used. Figure 2 Example of test assembly 6.2 Preparation for the test Ensure that the specimen and ball are
38、clean. Ultrasonic cleaning for 5 min in fresh petroleum ether followed by drying in ambient air is usually sufficient. The suitability of the ball shall be determined by measuring 10 diameters at random. A ball shall be rejected if the difference between any two measurements exceeds 5 m (the maximum
39、 allowable value of VDWS for grade G 200 balls as given in ISO 3290-1), or if scratches visible to the naked eye are present on the surface. Prepare a slurry of abrasive particles in a diluting agent. Position the test piece on a stable support. The abrasive slurry should be well stirred to ensure a
40、 uniform dispersion of abrasive particles. Hardened steel balls for rolling bearings, having a specified diameter and surface finish in accordance with ISO 3290-1, can be used. 6.3 Test parameters The test-specific parameters include: a) ball diameter; b) contact load; c) sliding speed; d) compositi
41、on and concentration of the abrasive suspension; e) slurry feed rate; f) duration of the test. Licensed CopyChinese University of Hong Kong, 11/04/2009 08:51, Uncontrolled Copy, (c) BSI BS ISO 26423:2009 ISO 26423:2009(E) ISO 2009 All rights reserved 5 The specimen-specific parameters include: surfa
42、ce quality (roughness, cleanliness); and optical contrast between coating(s) and substrate. 6.4 Example of test parameters Typical operating parameters are as follows: a) ball diameter: 25 mm; b) contact load: 0,25 N; c) rotational speed of ball: 100 r/min; d) composition of the abrasive slurry: 1 m
43、 grain size diamond paste suspended in ethanol, 1:4 concentration e) slurry feed rate: 20 drops/min; and f) test duration: 5 min. NOTE Optimum test conditions will differ for different specimens. The above conditions are typical for thin (3 m to 5 m thickness) hard coatings on metallic substrates, b
44、ut will depend on the wear resistance and thickness of the coating, etc. For these and other coatings, it might be necessary to make trial craters under a range of conditions to determine parameters suitable for the production of circular craters of sufficient depth to clearly delineate the substrat
45、e/coating interface. 7 Microscopic examination and measurement 7.1 Examination It is mandatory to clean the specimen prior to examination (see 6.2). An imaging technique with calibrated size measurement shall be used. Examine the ground cavity at the highest magnification at which the complete worn
46、crater is visible. Focus the microscope on the concentric patterns and if necessary adjust the illumination to obtain maximum contrast. Usually an optical reflected-light microscope is used, but any other imaging technique such as scanning electron microscopy may be used, e.g. when it is not possibl
47、e to discriminate between the coating and the substrate by other means. In the case of optical microscopy, etching may be used to enhance contrast between the substrate and coating. 7.2 Measurement Measure the crater dimensions as appropriate, using a calibrated measuring device. For flat specimens,
48、 measure the diameters D, d, or lengths X, Y, of the craters both parallel and perpendicular to the direction of ball rotation (Figure 1). For cylindrical specimens, measure only the largest dimensions of the craters parallel with the cylinder axis (Figure 3). At least 5 measurements shall be carrie
49、d out, to define the repeatability of the measurement. Licensed CopyChinese University of Hong Kong, 11/04/2009 08:51, Uncontrolled Copy, (c) BSI BS ISO 26423:2009 ISO 26423:2009(E) 6 ISO 2009 All rights reserved Due to surface roughness effects, the boundaries of the layer(s) may not be well defined and the best estimate of the centreline of a boundary shall be used. NOTE 1 Dimensions can easily be measured by preparing micrographs of the crater as well as of a traceably calibrated scale at the same magni
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