1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationDD ISO/TS 10798:2011Nanotechnologies Charaterization of single-wall carbon nanotubes usingscanning electron microscopyand energy dispersive X-rayspectrometry analysisDD ISO/TS 10
2、798:2011 DRAFT FOR DEVELOPMENTNational forewordThis Draft for Development is the UK implementation of ISO/TS10798:2011.This publication is not to be regarded as a British Standard.It is being issued in the Draft for Development series of publicationsand is of a provisional nature. It should be appli
3、ed on thisprovisional basis, so that information and experience of its practicalapplication can be obtained.Comments arising from the use of this Draft for Developmentare requested so that UK experience can be reported to theinternational organization responsible for its conversion toan internationa
4、l standard. A review of this publication willbe initiated not later than 3 years after its publication by theinternational organization so that a decision can be taken on itsstatus. Notification of the start of the review period will be made inan announcement in the appropriate issue of Update Stand
5、ards.According to the replies received by the end of the review period,the responsible BSI Committee will decide whether to support theconversion into an international Standard, to extend the life of theTechnical Specification or to withdraw it. Comments should be sentto the Secretary of the respons
6、ible BSI Technical Committee at BritishStandards House, 389 Chiswick High Road, London W4 4AL.The UK participation in its preparation was entrusted to TechnicalCommittee NTI/1, Nanotechnologies.A list of organizations represented on this committee can beobtained on request to its secretary.This publ
7、ication does not purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. BSI 2011ISBN 978 0 580 61380 7ICS 07.030Compliance with a British Standard cannot confer immunity fromlegal obligations.This Draft for Development was published under the
8、authority ofthe Standards Policy and Strategy Committee on 31 July 2011.Amendments issued since publicationDate Text affectedDD ISO/TS 10798:2011Reference numberISO/TS 10798:2011(E)ISO 2011TECHNICAL SPECIFICATION ISO/TS10798First edition2011-07-15Nanotechnologies Characterization of single-wall carb
9、on nanotubes using scanning electron microscopy and energy dispersive X-ray spectrometry analysis Nanotechnologies Caractrisation des nanotubes de carbone simple paroi par microscopie lectronique balayage et spectroscopie dispersion dnergie DD ISO/TS 10798:2011ISO/TS 10798:2011(E) COPYRIGHT PROTECTE
10、D DOCUMENT ISO 2011 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any 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 membe
11、r 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-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2011 All rights reservedDD ISO/TS 10798:2011ISO/TS 10798:2011(E) ISO 2011 All rights res
12、erved iiiContents Page Foreword iv Introduction . v 1 Scope 1 2 Normative references 1 3 Terms and definitions . 1 3.1 Terms related to scanning electron microscope . 1 3.2 Terms related to electron probe microanalysis . 2 3.3 Terms related to sampling 3 4 General principles . 4 4.1 SEM analysis 4 4
13、.2 EDX analysis 4 4.3 Applicability to MWCNT analysis . 4 4.4 Other supportive analytical methods 5 5 Sample preparation methods . 5 5.1 Precautions and safety concerns 5 5.2 Preparing samples for SEM/EDX analysis 5 5.3 SEM sample preparation/attachment techniques 6 6 Measurement procedures . 7 6.1
14、EDX analysis 8 7 Data analysis and results interpretation . 9 7.1 SEM results 9 7.2 EDX results 9 8 Measurement uncertainty . 9 8.1 SEM analysis 9 8.2 EDX analysis 10 Annex A (normative) SEM sampling methods . 11 Annex B (informative) Supportive information on EDX characterization of CNT materials 1
15、3 Annex C (informative) Case study for the analysis of as-synthesized and purified SWCNT samples 15 Annex D (informative) Examples of SEM/EDX analysis of SWCNTs . 22 Bibliography 26 DD ISO/TS 10798:2011ISO/TS 10798:2011(E) iv ISO 2011 All rights reservedForeword ISO (the International Organization f
16、or Standardization) 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 th
17、e 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 of electrotechnical standardization. Internat
18、ional 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 Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication
19、 as an International Standard requires approval by at least 75% of the member bodies casting a vote. In other circumstances, particularly when there is an urgent market requirement for such documents, a technical committee may decide to publish other types of normative document: an ISO Publicly Avai
20、lable Specification (ISO/PAS) represents an agreement between technical experts in an ISO working group and is accepted for publication if it is approved by more than 50% of the members of the parent committee casting a vote; an ISO Technical Specification (ISO/TS) represents an agreement between th
21、e members of a technical committee and is accepted for publication if it is approved by 2/3 of the members of the committee casting a vote. An ISO/PAS or ISO/TS is reviewed after three years in order to decide whether it will be confirmed for a further three years, revised to become an International
22、 Standard, or withdrawn. If the ISO/PAS or ISO/TS is confirmed, it is reviewed again after a further three years, at which time it must either be transformed into an International Standard or be withdrawn. Attention is drawn to the possibility that some of the elements of this document may be the su
23、bject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO/TS 10798 was prepared by Technical Committee ISO/TC 229, Nanotechnologies. DD ISO/TS 10798:2011ISO/TS 10798:2011(E) ISO 2011 All rights reserved vIntroduction Single-wall carbon nanotubes (SW
24、CNTs) are made from a unique form of carbon that has desirable mechanical, thermal and electronic properties. They are composed of carbon atoms arrayed in a hexagonal network in the shape of a hollow tube. SWCNT diameters are in the order of 0,5 nm to 3 nm, while SWCNT lengths can range from less th
25、an one m into the millimetre range. Possible applications for SWCNTs range from composite reinforcing materials, drug delivery systems and electronic devices, to mention a few. SWCNTs can be grown in situ as part of an electronic or electromechanical device, or produced in bulk through electric arc,
26、 laser or chemical vapour deposition methods. Details on the structure and manufacturing methods for SWCNTs can be found in relevant literature1218. The production of SWCNTs is driven by a catalyst-based growth mechanism, with metallic nanoparticles as the catalyst material. These nanoparticles can
27、be found in the raw, as produced SWCNT material. The raw material can also contain other impurities in the form of inorganic oxides, along with different nanocarbon structures such as fullerenes, nanocrystalline carbon and amorphous carbon. Solvents, acids and other chemical agents are used to purif
28、y the raw SWCNT materials. Impurities are reduced or removed during the purification process. Some of the purification methods include oxidation by acid reflux17, gas phase oxidation14, microfiltration11, and column chromatography15. However, depending on the purification method, the SWCNTs can be s
29、hortened in length, functionalized with acid groups, bundled (many SWCNTs adhered together), or damaged (defects in the wall structure that can affect the properties of the material). High resolution scanning electron microscopy is an extremely useful technique for characterizing both raw and purifi
30、ed SWCNT materials. The high resolution scanning electron microscope (HRSEM) is used here to differentiate features that are consistent with high-aspect ratio carbon nanotubes from other non-filamentous carbon impurities. SEM-based energy dispersive X-ray spectrometry (EDX) analysis is also used to
31、identify the elemental composition of catalysts and other inorganic impurities in the material. DD ISO/TS 10798:2011DD ISO/TS 10798:2011TECHNICAL SPECIFICATION ISO/TS 10798:2011(E) ISO 2011 All rights reserved 1Nanotechnologies Characterization of single-wall carbon nanotubes using scanning electron
32、 microscopy and energy dispersive X-ray spectrometry analysis 1 Scope This Technical Specification establishes methods to characterize the morphology, and to identify the elemental composition of, catalysts and other inorganic impurities in raw and purified single-wall carbon nanotube (SWCNT) powder
33、s and films, using scanning electron microscopy and energy dispersive X-ray spectrometry analysis. The methods described here for SWCNTs can also be applied to the analysis of multiwall carbon nanotubes (MWCNTs). 2 Normative references The following referenced documents are indispensable for the app
34、lication of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 22493:2008, Microbeam analysis Scanning electron microscopy Vocabulary ISO/TS 80004-3, Nanotechnologies Vocab
35、ulary Part 3: Carbon nano-objects 3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 22493:2008 and ISO/TS 80004-3 and the following apply. 3.1 Terms related to scanning electron microscope 3.1.1 SEM scanning electron microscope instrument that produces
36、 magnified images of a specimen by scanning its surface with a well-focused electron beam NOTE 1 See Reference 16 for details of the instrumentation, the SEM process and the different types of SEMs. NOTE 2 A conventional SEM utilizes an electron source filament either made from W or LaB6materials th
37、at are heated to produce a source of electrons by thermionic emission. The electron beam probe sizes (dp) are between 3 nm and 4 nm, which is not sufficient to resolve individual SWCNTs. The range of useful analysis is generally under 100 000 magnification and can be considerably less in non-conduct
38、ing materials. Conventional SEMs typically operate at high accelerating voltages (5 kV to 30 kV) and often require the samples to be coated. These SEMs can be used for EDX analysis. DD ISO/TS 10798:2011ISO/TS 10798:2011(E) 2 ISO 2011 All rights reservedNOTE 3 A field emission scanning electron micro
39、scope (FESEM) has an extremely fine cathode tip that generates a smaller diameter probe size compared to a conventional SEM, even at very low accelerating voltages (0,5 kV to 5 kV). In FESEMs, electron beam probe sizes can be 1 nm or less, expanding the useful magnification range an order of magnitu
40、de higher. Non-conducting materials can be imaged without applying a conductive coating through the use of low accelerating voltages. An FESEM is sometimes referred to as a high resolution SEM (HRSEM). This can also be used for EDX analysis and offers better spatial resolution when low accelerating
41、voltages are used. NOTE 4 Variable pressure SEM (VPSEM) is another type of SEM where the pressure around the specimen can be controlled from a few Pa to hundreds of Pa, to eliminate surface charging and to minimize surface damage to the specimen. Although currently outside the scope of this specific
42、ation, this method is included here to provide the basis for possible future VPSEM characterization of SWCNTs that might be present in biological tissue or in a fluid environment. In this case, EDX analysis is possible but electron beam scattering in the residual gas means that results from point an
43、alysis are contaminated by spurious contributions from all over the specimen stub. 3.2 Terms related to electron probe microanalysis 3.2.1 accelerating voltage potential difference applied between the filament and the anode to accelerate the electrons emitted from the source ISO 23833:2006, definiti
44、on 4.1 3.2.2 analysis depth maximum depth from which a defined fraction (e.g. 95% of the total) of the X-rays are emitted from the interaction volume after absorption ISO 23833:2006, definition 4.7.1.2 3.2.3 analysis volume volume from which a defined fraction (e.g. 95% of the total) of the X-rays a
45、re emitted after generation and absorption ISO 23833:2006, definition 4.7.1.3 3.2.4 BE backscattered electron electron ejected through the entrance surface of a sample by a backscattering process NOTE 1 By convention, an electron ejected with an energy greater than 50 eV may be considered as a backs
46、cattered electron. NOTE 2 Adapted from ISO 23833:2006. 3.2.5 BEI backscattered electron image scanning electron beam image in which a signal is derived from a dedicated backscattered electron detector (e.g. passive scintillator, solid-state diode, channel plate or negatively-biased Everhart-Thornley
47、 detector) ISO 23833:2006, definition 3.4.2 3.2.6 coating artefact undesirable modification of the sample structure and/or X-ray spectrum arising from the characteristics of the coating material and which may interfere with the interpretation of the true sample details NOTE Adapted from ISO 23833:20
48、06. DD ISO/TS 10798:2011ISO/TS 10798:2011(E) ISO 2011 All rights reserved 33.2.7 EDS energy dispersive X-ray spectrometer device for determining X-ray intensity as a function of the energy of the radiation ISO 23833:2006, definition 3.6.4 3.2.8 EDX energy dispersive X-ray spectrometry form of X-ray
49、spectrometry in which the energy of the individual photons is measured and is used to build up a digital histogram representing the distribution of X-rays with energy ISO 23833:2006, definition 3.6.5 3.2.9 EPMA electron probe microanalysis technique of spatially-resolved elemental analysis based upon electron-excited X-ray spectrometry with a focused electron probe and an electron interaction volume with micrometer to sub-micrometer dimensions ISO 23833:2006, definition 2.1 3.2.10 point analysis anal
