© ISO 2017 Fine ceramics (advanced ceramics, advanced technical ceramics) — Test method for determining elastic modulus of thick ceramic coatings at elevated temperature Céramiques techniques — Méthod[.]
INTERNATIONAL STANDARD ISO 20343 First edition 2017-01 Fine ceramics (advanced ceramics, advanced technical ceramics) — Test method for determining elastic modulus of thick ceramic coatings at elevated temperature Céramiques techniques — Méthode d’essai relative la détermination du module élastique des revêtements de céramique épais température élevée Reference number ISO 20343:2017(E) © ISO 2017 ISO 03 43 :2 017(E) COPYRIGHT PROTECTED DOCUMENT © ISO 2017, Published in Switzerland All rights reserved Unless otherwise specified, no part o f this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission Permission can be requested from either ISO at the address below or ISO’s member body in the country o f the requester ISO copyright o ffice Ch de Blandonnet • CP 401 CH-1214 Vernier, Geneva, Switzerland Tel +41 22 749 01 11 Fax +41 22 749 09 47 copyright@iso.org www.iso.org ii © ISO 2017 – All rights reserved ISO 20343:2017(E) Contents Page Foreword iv Scope Normative references Terms and definitions Principle Apparatus 5.1 5.3 5.4 5 Elastic modulus testing machine 5.2.1 General f 5.2.4 Furnace heating rate Temperature measuring and indicating instruments 5.3.1 General 5.3.2 Thermocouples f Dimension-measuring device 5.5.1 General 5.5.2 Fixture material H eating sys tem 2 Temp erature s tab ility Tes t temp erature uni o rmity 5 Furnace s tab ility 3 Verificatio n o the thermo co up le temp erature meas uring sys tem Tes t fixture Test pieces Test procedure Calculation of results Analysis of precision and uncertainty 10 6.1 6.2 Test piece size Test piece preparation and storage 7.1 7.2 Measurement of the size and mass of the test-pieces Measurement of elastic modulus of coating at elevated temperature 8.1 8.2 8.3 Standard formula for elastic modulus of coating Mean value and standard deviation for elastic modulus Variation of elastic modulus with temperature Test report Bibliography © ISO 2017 – All rights reserved iii ISO 20343:2017(E) Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies) The work o f preparing International Standards is normally carried out 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 collaborates closely with the International Electrotechnical Commission (IEC) on all matters o f electrotechnical standardization The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part In particular the different approval criteria needed for the di fferent types o f ISO documents should be noted This document was dra fted in accordance with the editorial rules of the ISO/IEC Directives, Part (see www.iso.org/directives) Attention is drawn to the possibility that some o f the elements o f this document may be the subject o f patent rights ISO shall not be held responsible for identi fying any or all such patent rights Details o f any patent rights identified during the development o f the document will be in the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents) Any trade name used in this document is in formation given for the convenience o f users and does not constitute an endorsement For an explanation on the meaning o f ISO specific terms and expressions related to formity assessment, as well as information about ISO’s adherence to the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following URL: www.iso.org/iso/foreword.html This document was prepared by Technical Committee ISO/TC 206, Fine ceramics iv © ISO 2017 – All rights reserved INTERNATIONAL STANDARD ISO 20343:2017(E) Fine ceramics (advanced ceramics, advanced technical ceramics) — Test method for determining elastic modulus of thick ceramic coatings at elevated temperature Scope This document specifies a method o f test for determining the elastic modulus o f thick ceramic monolayer coatings (thickness > 0,03 mm) at elevated temperatures, using the impulse excitation method Procedures for test piece preparation, test modes and rates (load rate or displacement), data collection, and reporting procedures are given This document applies primarily to brittle ceramic coatings on ceramic or metal substrates This test method can be used for material research, quality control, and characterization and design data- generation purposes Normative references The following documents are re ferred to in the text in such a way that some or all o f their content constitutes requirements o f this document For dated re ferences, only the edition cited applies For undated re ferences, the latest edition o f the re ferenced document (including any amendments) applies ISO 3611, Geometrical product specifications (GPS) — Dimensional measuring equipment: Micrometers for external measurements — Design and metrological characteristics ISO 17561, Fine ceramics (advanced ceramics, advanced technical ceramics) — Test method for elastic moduli of monolithic ceramics at room temperature by sonic resonance IEC 60584-1, Thermocouples — Part 1: EMF specifications and tolerances Terms and definitions For the purposes o f this document, the following terms and definitions apply ISO and IEC maintain terminological databases for use in standardization at the following addresses: — IEC Electropedia: available at http://www.electropedia.org/ — ISO Online browsing platform: available at http://www.iso.org/obp 3.1 elastic modulus ratio of plane stress to plane strain Note to entry: Also known as Young’s modulus 3.2 flexural vibrations vibrations that occur when the displacements in a slender rod or bar are in a plane normal to the length dimension 3.3 thickness ratio ratio of the coating thickness to the substrate thickness © ISO 2017 – All rights reserved ISO 20343:2017(E) Principle The elevated temperature elastic modulus of ceramic coatings on metal or ceramic substrates is the interface between the coating and the substrate is continuous and without a debonding zone The elastic modulus of ceramic coatings can be calculated from three parameters, i.e the elastic modulus of the uncoated sample or substrate (Es), equivalent elastic modulus of the coated sample (Eq ), and the ratio of the coating thickness to the substrate thickness (R = h/H) The value of Eq and Es are determined deduced by comparing the elastic moduli o f coated and uncoated samples, under the precondition that by the impulse excitation technique Apparatus 5.1 Elastic modulus testing machine A suitable impulse excitation testing system capable o f applying impulses at elevated temperatures shall be used, which shall be in accordance with ISO 17561 Since the test piece is required by ISO 17561 to be homogeneous and isotropic, the measured modulus using the coated test piece is then described as an equivalent elastic modulus 5.2 Heating system 5.2.1 General The heating system, usually a furnace, shall be capable o f heating the test fixture and test piece and maintaining a uniform and constant temperature during the impulse excitation test The furnace shall have the capability for containing air, inert gas, or a vacuum environment as required for the test 5.2.2 Temperature stability The furnace shall be controlled by a device capable o f maintaining a constant temperature within ±2 °C or better within its working space during the time when the elastic modulus of test pieces is being measured 5.2.3 Test temperature uniformity The furnace shall be capable o f maintaining a uni form test piece temperature It shall previously be determined that the temperature o f the test piece does not vary by more than 0,5 % o f the test temperature a fter a 15 hold time at the required test temperature measured in °C 5.2.4 Furnace heating rate The furnace control device shall be capable o f maintaining a heating rate o f the furnace o f °C/min to 10 °C/min and preventing temperature overshoots 5.2.5 Furnace stability The time for the system to reach thermal equilibrium at the test temperature shall be determined for the test temperature to be used 5.3 Temperature measuring and indicating instruments 5.3.1 General The thermocouple temperature measuring equipment shall have a resolution o f at least °C and an accuracy o f °C or better Optical pyrometers, i f used, shall have a resolution o f better than °C and an accuracy o f °C or better © ISO 2017 – All rights reserved ISO 20343:2017(E) 5.3.2 Thermocouples Thermocouples in accordance with IEC 60584-1 shall be used The thermocouple shall exhibit low thermal inertia (the diameter of the wires shall not be greater than 0,5 mm) The measuring thermocouple tip shall be less than mm from the test piece, but never contact the test piece 5.3.3 Verification o f the thermocouple temperature measuring system Thermocouples shall be calibrated periodically against national standards since calibration may dri ft with usage or contamination 5.4 Dimension-measuring device A Vernier caliper with a precision of 0,02 mm according to ISO 3611 should be used to measure the dimensions o f the test piece The thickness o f the coating shall be measured by using a traceably calibrated optical or scanning electron microscope (SEM) with magnification o f 000 times or better 5.5 Test fixture 5.5.1 General The fixture shall be suitable for the installation o f the test piece as recommended in ISO 17561 with platinum hanging wires and for impulse excitation and signal acquisition in the furnace The fixture shall maintain the position of the test piece during the test 5.5.2 Fixture material The fixture shall be manu factured from a material that is inert under the testing conditions used The fixture shall be oxidation-resistant i f the testing is conducted in air The fixture shall have negligible chemical reaction with and shall not contaminate the test piece Test pieces 6.1 Test piece size A rectangular test bar with coating on one o f the two largest faces only is required The geometrical dimensions o f the coated sample are displayed in Figure The thickness ratio, R (R = h/H ), shall be larger than 1/100 For flexural resonance, the length o f the specimen (L) shall be greater than 40 mm The ratio of length to thickness of substrate, L/H, shall be greater than 20 The ratio of width to thickness of substrate, B/H, shall be in the range of to 10 The parallelism tolerance on opposite longitudinal faces is 0,015 mm Table shows the recommended dimensions of a ceramic-coated test piece The sur face o f the test piece shall be smooth and flat The sur face shall be ground using a fine grit (400 grit or finer) Any machining procedure used shall not a ffect the results The edges o f the test piece shall not be chamfered Key coating substrate Figure — Schematic illustration of the rectangular test pieces © ISO 2017 – All rights reserved ISO 03 43 : 01 7(E) Table — Recommended dimensions for coated tes t piece Dimensions in millimetres D imension Description Length of the bar Width of the bar Total thickness of the bar L B H +h Value Tolerance > 40 ±0,5 to 20 to ± ,1 ±0,05 An approximate ratio for L: B:(H + h) = 20:5:1 is recommended for elastic modulus measurement of thick ceramic coating with h h /H > , m m a nd > 6.2 > , 01 Test piece preparation and storage T he te s t pie ce s may b e ob ta i ne d u s i ng one o f the two appro ache s a) T he te s t pie ce s are c ut from s ome co ate d comp onents , c a re fu l ly gri nd i ng and p ol i s h i ng the te s t pie ce to ke ep the s u r face s p ara l lel and flat b) T he te s t pie ce s are prep a re d b y co ati ng a s ub s trate; i n th i s c as e, the mo du lu s o f the s ub s trate s l l be measured before depositing the coating The detailed test procedure is described below Before applyi ng the co ati ng , mark e ach te s t pie ce s ub s trate with a u n ique identi fier wh ich wi l l b e vi s ible a fter co ati ng M e as u re the flatne s s o f e ach u nco ate d te s t pie ce, for e xample, b y mou nti ng i n an u n s tre s s e d s tate on the x-y s tage o f a c a l ibrate d op tic a l m icro s cop e and me as u ri ng the z co ord i nate o f the s ur face with an acc u rac y o f ± µm at 10 e qua l ly s p ace d p o s ition s a long its leng th Re cord the results for each test piece T he te s t pie ce s sh a l l be nd le d c a re fu l ly to avoid the i ntro duc tion o f damage a fter te s t pie ce prep a ration T he te s t pie ce s s l l b e s tore d s ep a rately a nd no t a l lowe d to i mp ac t or s c ratch e ach o ther A minimum of test pieces is required for the test 7.1 Test procedure Measurement of the size and mass of the test-pieces D r y the te s t pie ce s u nti l thei r ma s s i s s ta nt Weigh e ach o f the te s t pie ce s to the ne a re s t mg or ,1 % (wh ichever i s gre ater) u s i ng a c a l ibrate s c a le Me a s u re the leng th o f co ate d te s t pie ce to the ne are s t , m m or ,1 % (wh ichever i s gre ater) M e as u re the th ickne s s o f co ati ng and the s ub s trate to ne are s t , 01 m m or ,1 % (wh ichever i s gre ater) Me as u re the d i men s ion s o f the te s t pie ce s u s i ng a Vern ier c a l ip er complyi ng with I S O 611 and with precision of 0,02 mm or better, or other calibrated measuring device providing the same or better to 5.5 (at the middle and two ends of the bar) and determine the average of the three measurements me a s urement acc u rac y M e as u re the width a nd th ickne s s at th re e p oi nts a long its leng th accord i ng C o ati ng th ickne s s sha l l b e me a s u re d b y u s i ng a ca l ibrate d op tic a l or s c a nn i ng ele c tron m ic ro s cop e (S E M ) with magni fic ation o f 0 ti me s or b e tter The variation in coating thickness between the thickest and thinnest values measured shall be less than or e qua l to 10 % I f the va riation i s more th an th i s , prep a re new te s t pie ce s me e ti ng th i s re qu i rement Care needs to be taken with the preparation of the side of the sample so that good contrast is obtained between the coating and substrate so that good measurements of coating thickness can be obtained 7.2 Measurement of elastic modulus of coating at elevated temperature Su s p end one o f the te s t pie ce s , s upp or te d b y a he at-re s i s ti ng materia l l i ke pl ati nu m wi re i n accordance with ISO 17561, as shown in Figure 2, in the furnace The suspending devices shall permit the free vibration of the test piece The elastic modulus of the substrate shall be known, or be measured at the temperature or temperatures of interest, using an uncoated sample © ISO 2017 – All rights reserved ISO 20343:2017(E) a ) I m p u l s e e x c i t a t i o n t e s t i n g m e t h o d b) Recommended support system Key s up p o rt sys tem impulser furnace specimen transducer s ignal amp lifier frequency analyzer results output F i g u r e — S c h e m a t i c i l l u s t r a t i o n o f i m p u l s e e x c i t a t i o n t e s t i n g m e t h o d a n d r e c o m m e n d e d support system H e at the te s t pie ce to the te s ti ng temp eratu re a nd hold it at th i s temp eratu re for a s u ffic ient ti me (1 is recommended) for the specimen temperature to reach equilibrium The time allowed for this shall be s tate d i n the te s t rep or t T he temp eratu re me as u re d b y the thermo couple or o ther me a s uri ng device sh al l no t var y du ri ng the ti me o f the te s ti ng by more tha n ± , % o f the te s t temp eratu re me a s ure d i n ° C E xcite fle xu l re s ona nce o f the s ample s by app lyi ng an i mpu l s e a nd me as u re the fre quenc y o f the resonance generated Determine the elastic modulus of substrate, Es , and the elastic modulus of coated test pieces, Eq f , accord i ng to I S O 175 61 , re s p e c tively Te s t re s u lts sh a l l b e ob tai ne d rom at le as t co ate d te s t pie ce s , a l l o f wh ich were co ate d at the s a me ti me b y the s ame pro ce s s © ISO 2017 – All rights reserved ISO 03 43 : 01 7(E) Calculation of results 8.1 Standard formula for elastic modulus of coating The standard formula for the elastic modulus of the coating, Ec Ec = where −A + A2 + C 2R , i s given b y Formula (1): (1) ⋅ Es R =h/H (2) F = (1 + R ) ⋅ ( E q / E s ) (3) A = 4R + R + − F (4) C = 4R ⋅ ( F − ) (5) where h i s the th ickne s s o f cera m ic co ati ng , i n m m; H i s the th ickne s s o f the s ub s trate, i n m m; Eq i s the el as tic mo du lu s o f co ate d s p e ci men, i n GPa; is the elastic modulus of substrate, in GPa Determine the thickness ratio, R, using Formula (2) and the stiffness ratio of the substrate sample to the coated sample, F, using Formula (3) Calculate the values of A and C using Formula (4) and Formula (5), f Ec , can then be obtained using Formula (1) Thus, the test procedure for coating’s modulus has three steps Es re s p e c tively T he ela s tic mo du lu s o the co ati ng , a) M e a s u re the mo du lu s o f co ate d te s t pie ce var yi ng with temp eratu re b) Te s t the mo du lu s o f the s ub s trate var yi ng with temp eratu re c) Calculate the modulus of the coating at different temperatures 8.2 Mean value and standard deviation for elastic modulus The mean elastic modulus, E , and the standard deviation, s , are given by Formula (6) and Formula (7): © ISO 2017 – All rights reserved ISO 20343:2017(E) n ∑ Ei E = i =1 n n ( Ei − E ) s = i =1 n −1 ∑ (6) /2 (7) where E i n is the elastic modulus of the th test piece; is the total number of test pieces i 8.3 Variation of elastic modulus with temperature As it is unlikely that the temperature o f operation o f the ceramic coating will be well-established or even constant, it is usual to determine the elastic moduli of coated and uncoated specimens under a range of temperatures to enable a plot of modulus versus temperature to be obtained At each testing temperature, the elastic modulus of the ceramic coating should be deduced, from which the curve of the relationship between the elastic modulus of the coating and testing temperatures can be derived Figure shows schematic results of elastic modulus for coated sample (Eq ) and substrate (Es) at di fferent temperatures by the impulse excitation tests and the calculated elastic modulus o f the coating (Ec) at these temperatures Key X Y testing temperature (°C) elastic modulus (GPa) Figure — Schematic results of elastic modulus of coating (Ec) changed with the elastic modulus of coated test piece (Eq ) and substrate (Es) at different temperatures (T) © ISO 2017 – All rights reserved ISO 03 43 : 01 7(E) Analysis of precision and uncertainty T he pre ci s ion o f the mo du lu s me a s urement o f the co ati ng i nvolve s ma ny fac tors , e g the un i form ity o f the th ickne s s , e ffe c ts o f the th ickne s s ratio , and i nter face de fe c ts I n order to ge t the re a s onabi l ity o f the calculation, it is supposed that the interface bonding between the coating and substrate is continuous and u n i form H owever, i n many c a s e s , the i nter face b ond i ng i s no t p er fe c tly conti nuou s , wh ich re s u lts i n a l ittle lower data o f the me as u re d mo du lu s T h i s u ncer tai nty problem tests is more sensitive than the three-point bending tests T he pre c i s ion o f me a s u rement o f fu nda menta l mo de natu l fre quenc y, test pieces should meet the requirements as described in ISO 17561 for the i mpu l s e e xcitation d i men s ion s , and ma s s o f the Test report The test report shall contain at least the following information: a) the na me and add re s s o f the te s ti ng e s tabl i sh ment; b) the date o f the te s t, c u s tomer name a nd add re s s , a nd s ignator y; c) a re ference to th i s c u ment, i e I S O 03 43 ; d) the te s t pie ce sh ap e, s i z e, a nd the th ickne s s ratio; e) a de s crip tion o f the s ub s trate materia l (materia l typ e a nd any pre - and p o s t-tre atment o f the s ub s trate) and o f the co ati ng and co ati ng pro ce s s; f) the te s t temp eratu re, typ e o f he ati ng element, temp erature me as u ri ng device; g) the h) the approxi mate rate o f he ati ng and hold ti me at the te s t temp eratu re prior to the te s t; i) the nu mb er o f te s ts c arrie d out a nd the nu mb er o f va l id re s u lts ob tai ne d; j) the va l id re s u lts , me an va lue, and s ta ndard deviation s o f the elas tic mo du lu s; k) the temp eratu re and hu m id ity o f the lab orator y fu rnace envi ron ment: a i r, vac uum, or i ner t atmo s phere; © ISO 2017 – All rights reserved ISO 03 43 : 01 7(E) Bibliography [1] [2] ISO 18558, Fine ceramics (advanced ceramics, advanced technical ceramics) — Test method for determining elastic modulus and bending strength o f ceramic tube and rings B ao hou u f relative method Mater Sci Eng A 2007, (1-2) pp 268–274 B ao , Wang W., hou Investigation of the relationship between elastic modulus and hardness based on depth-sensing indentation measurements Acta Mater 2004, , pp 5397–5404 B ao hou f SiC and Ti3 AlC ceramics Mater Lett 2003, , pp 4018–4022 Y.W , Z Y C , B X X E va luati ng el as tic mo du lu s a nd s treng th o h ard co ati ngs b y 45 [3] Y.W Z Y C 52 [4] Y.W , & Z Y C E va luati ng h igh-temp eratu re mo du lu s and ela s tic re cover y o Ti 57 © ISO 2017 – All rights reserved ISO 03 43 :2 017(E) ICS 81.060.30 Price based on pages © ISO 2017 – All rights reserved