1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS ISO 14188:2012Metallic and other inorganiccoatings Test methodsfor measuring thermal cycleresistance and thermal shockresistance for thermal barriercoatingsBS ISO 14188:2012 B
2、RITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 14188:2012. The UK participation in its preparation was entrusted to TechnicalCommittee STI/40, Thermally sprayed inorganic finishes.A list of organizations represented on this committee can be obtained on request
3、to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2012. Published by BSI Standards Limited 2012ISBN 978 0 580 69103 4 ICS 25.220.20 Compliance with a British S
4、tandard cannot confer immunity from legal obligations.This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 October 2012.Amendments issued since publicationDate T e x t a f f e c t e dBS ISO 14188:2012 ISO 2012Metallic and other inorganic coatin
5、gs Test methods for measuring thermal cycle resistance and thermal shock resistance for thermal barrier coatingsRevtements mtalliques et autres revtements inorganiques Mthodes dessai pour mesurer la rsistance au cyclage thermique et la rsistance au choc thermique des revtements barrires thermiquesIN
6、TERNATIONAL STANDARDISO14188First edition2012-10-15Reference numberISO 14188:2012(E)BS ISO 14188:2012ISO 14188:2012(E)ii ISO 2012 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2012All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any
7、form or by 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 officeCase postale 56 CH-1211 Geneva 20Tel. + 41 22 749 01 11Fax + 41 22 749 09 4
8、7E-mail copyrightiso.orgWeb www.iso.orgPublished in SwitzerlandBS ISO 14188:2012ISO 14188:2012(E) ISO 2012 All rights reserved iiiContents PageForeword ivIntroduction v1 Scope 12 Normative references . 13 Terms and definitions . 14 Principle . 35 Test methods 35.1 General . 35.2 Thermal cycle resist
9、ance method . 35.3 Thermal shock resistance method .106 Test reports .136.1 General .136.2 Test report of thermal cycle resistance method .146.3 Test report of thermal shock resistance method 14Bibliography .15BS ISO 14188:2012ISO 14188:2012(E)ForewordISO (the International Organization for Standard
10、ization) is a worldwide federation of national standards bodies (ISO member bodies). The work of 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
11、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 of electrotechnical standardization.International Standa
12、rds 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 Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an Intern
13、ational 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 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 14188 was
14、prepared by Technical Committee ISO/TC 107, Metallic and other inorganic coatings.iv ISO 2012 All rights reservedBS ISO 14188:2012ISO 14188:2012(E)IntroductionThermal barrier coatings are highly advanced material systems, generally applied to surfaces of hot-section parts made of nickel or cobalt ba
15、sed superalloys, such as blades, vanes and combustors in gas turbines and aero-engines, operated at elevated temperatures.The purpose of these coatings is to insulate metallic components for an extended period at elevated temperatures by employing thermally insulating materials which can sustain an
16、appreciable temperature difference between load bearing alloys and coating surfaces. By shielding these parts, these coatings permit the use of high operating temperatures by restricting exposure of structural parts to these temperatures, thereby extending their lives.This International Standard spe
17、cifies test methods, applicable to these thermal barrier coatings, for measuring thermal cycle resistance and thermal shock resistance using appropriate heating and cooling procedures. ISO 2012 All rights reserved vBS ISO 14188:2012BS ISO 14188:2012Metallic and other inorganic coatings Test methods
18、for measuring thermal cycle resistance and thermal shock resistance for thermal barrier coatings1 ScopeThis International Standard specifies test methods applicable to thermal barrier coatings for measuring thermal cycle resistance by using steady cyclical heating and cooling procedures, and for mea
19、suring thermal shock resistance using a heating and quenching technique.These measurements are used for the evaluation of durability of thermal barrier coatings to thermal strain.This International Standard is applicable for screening thermal barrier coating systems including materials and processin
20、g, and not for controlling the thermal spraying processes.2 Normative referencesThe following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (incl
21、uding any amendments) applies.ISO 14232, Thermal spraying Powders Composition and technical supply conditionsISO 14916, Thermal spraying Determination of tensile adhesive strength3 Terms and definitionsFor the purposes of this document, the following terms and definitions apply.3.1thermal barrier co
22、atingTBCtwo-layer coating consisting of a metallic bond coat and an oxide top coat, in order to reduce heat transfer from outside the top coat through the coating to the base materialNOTE When a TBC is exposed to operating at a high temperature, thermally grown oxide (TGO) develops on the top of the
23、 bond coat. The substrate is a typically heat-resistant high nickel based alloy class, UNS N 06002 type of material. The coatings, illustrated in Figure 1, are applied by using physical or chemical vapour deposition or by thermal spray processes, such as plasma spray and high velocity oxy-fuel (HVOF
24、) spray conforming to ISO 14232.INTERNATIONAL STANDARD ISO 14188:2012(E) ISO 2012 All rights reserved 1BS ISO 14188:2012ISO 14188:2012(E)56813 4279Key1 combustion gas temperature2 top coat3 TGO4 bond coat5 thermal barrier effect6 temperature7 TBC8 cooling air temperature9 substrateFigure 1 Diagramma
25、tic view of the section and effects of TBC3.2thermally grown oxideTGOoxide grown between top and bond coat when the coating system is heated3.3ratio of spalling areasproportion of the total spalling area relative to the effective area of the TBC3.4critical number of cycles to spallingnumber of therm
26、al cycles immediately prior to achieving 30 % in ratio of spalling areaNOTE In the assessment of spalling area, areas of delamination or cracking are excluded.3.5thermal shock temperature differencedifference in temperatures between heating and cooling water treatments of the test pieces in thermal
27、shock tests3.6thermal shock resistancethermal shock temperature difference that causes a reduction of tensile adhesive strength immediately prior to a decrease of 30 % relative to the tensile adhesive strength in the absence of thermal shock2 ISO 2012 All rights reservedBS ISO 14188:2012ISO 14188:20
28、12(E)4 PrincipleThe test methods include the thermal cycle resistance test by using steady cyclical heating and cooling procedures and consist of measuring ratio of spalling areas, and the thermal shock resistance test by measuring tensile adhesive strength following application of thermal shock. Th
29、ermal shock is applied by heating the test pieces in a furnace to the appropriate temperature and quenching in water. The coatings are applied by physical, chemical vapour deposition or by thermal spray processes such as plasma spray and high velocity oxy-fuel (HVOF) spray by using feedstock powders
30、 (ISO 14232).5 Test methods5.1 Generala) All measurements related to physical quantities, dimensions and quantities and unit systems shall be carried out in accordance with appropriate International Standards (see Bibliography).b) When ordering testing in accordance with this International Standard,
31、 agreement between the contracting parties are needed in writing in contract or purchase order, concerning the following:1) handling and sectioning procedures, method of application of coatings, whether the coating surface is to be used as coated;2) for the thermal cycle test, selection of test piec
32、es, position and size of piercing on test pieces, number of and any interruption of thermal cycles, and upper limit of high temperature, heating time, holding time at high temperature, cooling time and holding time at low temperature of a thermal cycle.5.2 Thermal cycle resistance method5.2.1 Genera
33、lThe test method covers a thermal cycle resistance test by using steady cyclical heating and cooling procedures and consists of measuring ratio of spalling areas. This method is useful in the selection of materials, coating processes and process conditions in the TBC system used in gas turbines oper
34、ating at elevated temperatures.5.2.2 ApparatusThe apparatus consists of a heating and cooling device and temperature control system, and is shown in Figure 2. ISO 2012 All rights reserved 3BS ISO 14188:2012ISO 14188:2012(E)23178564a) Vertical typeKey1 heating and cooling device2 high-temperature bat
35、h3 low-temperature bath4 test piece5 thermocouple6 temperature controller7 temperature control system8 test-piece-moving deviceFigure 2 Typical device for thermal cycle resistance method (continued)4 ISO 2012 All rights reservedBS ISO 14188:2012ISO 14188:2012(E)65431279108b) Horizontal typeKey1 test
36、 piece support2 test piece3 shield plate (up/down possible)4 thermocouple5 temperature controller6 temperature control system7 test-piece-moving device 8 high-temperature bath9 low-temperature bath10 heating and cooling deviceFigure 2 Typical device for thermal cycle resistance method5.2.2.1 Heating
37、 and cooling devicea) The heating and cooling device consists of high- and low-temperature baths respectively. The atmosphere in both baths is air.b) The test piece is placed alternately in the two baths which are fixed; or alternatively, the test piece is fixed and the baths are alternated.c) The t
38、est pieces may be directly exposed to ambient air instead of using the low-temperature bath.d) The temperature control system consists of the temperature controller and thermocouples (see Figure 2). The temperature is regulated to ensure that the temperature of the test pieces is within the range gi
39、ven in Table 1. ISO 2012 All rights reserved 5BS ISO 14188:2012ISO 14188:2012(E)Table 1 Permissible temperature deviation from the target test temperature of test piecesTest temperatureCPermissible deviation CRoom temperature to 600 3 600 to 800 4 800 to 1 000 5 1 000 75.2.3 Test pieces5.2.3.1 Test
40、piecesThe test pieces shall be of the flat plate type (Figure 3) or the disk type (Figure 4). To facilitate handling, the test pieces may be pierced.Chamfering or rounding of the substrate edges shall appropriately be applied in order to avoid stress concentration at these locations.5.2.3.2 Measurem
41、ent of dimensionsMeasure the dimensions of the parts to the nearest 0,1 mm using appropriate instruments see 5.1.a).5.2.3.3 Measurement of mass of test piecesWeigh the test pieces to the nearest 1 mg using appropriate instruments see 5.1.a).labbtcKeyl lengthb widtht total thicknessa20 mm to 100 mmb2
42、0 mm to 50 mmc1,5 mm to 12,7 mmThe shaded area is covered with the TBC.Figure 3 Shape and dimensions of flat-plate-type test piece6 ISO 2012 All rights reservedBS ISO 14188:2012ISO 14188:2012(E)DatbKeyD outside diametert total thicknessa20 mm to 40 mmb1,5 mm to 5,0 mmThe shaded area is covered with
43、the TBC.Figure 4 Shape and dimensions of disk-type test piece5.2.4 Test procedures5.2.4.1 Heating and cooling methodsTest pieces are held in the low-temperature bath before transferring them to the high-temperature bath and are held there for a specified duration. Once the test pieces have achieved
44、stability, they are then relocated to the low-temperature bath and held there for a specified duration. A thermal cycle, shown in Figure 5, therefore, consists of a period of stability in the low-temperature bath and subsequently a period of stability in the high-temperature bath at the specified te
45、mperature.The temperatures at the high and low temperature are calibrated by attaching thermocouples to dummy test pieces for adjustment to the specified temperature prior to the actual test runs.The number of thermal cycles is referred to in 5.1 b) 2). ISO 2012 All rights reserved 7BS ISO 14188:201
46、2ISO 14188:2012(E)11105678931YX20090024Key1 start2 lower limit3 temperature at high temperature4 upper limit5 temperature at low temperature6 heating time7 holding time at high temperature8 cooling time9 holding time at low temperature10 1 cycle11 N cycles (N: 1, 2, 3, )X timeY temperature, T (C)Fig
47、ure 5 A typical thermal cycle5.2.4.2 Heating and cooling conditionsa) Table 1 shows the permissible temperature deviation from the target test temperature. For the high test temperature, the lower limit shall be 900 C; and for the low test temperature, the upper limit shall be 200 C. For the upper l
48、imit of the high-temperature range, see 5.1.b) 2).b) An example of a temperature pattern for a thermal cycle, shown in Figure 5, consists of 10 min for a temperature rise from 200 C to 900 C, 30 min for maintaining the test piece at the high temperature, 15 min for the temperature to drop from 900 C
49、 to 200 C, and 5 min for maintaining the test piece at the low temperature. Time conditions in a thermal cycle may be varied see 5.1 b) 2).c) Multiple test pieces may be treated simultaneously to enhance the efficiency of the test procedures.5.2.4.3 Examination for spalling during thermal cycle resistance testa) The test may be interrupted after completion of an agreed number of cycles and the test piece is allowed to cool down to 200 C and examined for any spalling. Once the number of
