National foreword

This Published Document is the UK implementation of IEC TS 62607‑2‑6:2024.

The UK participation in its preparation was entrusted to Technical Committee NTI/1, Nanotechnologies.

A list of organizations represented on this committee can be obtained on request to its committee manager.

Contractual and legal considerations

This publication has been prepared in good faith, however no representation, warranty, assurance or undertaking (express or implied) is or will be made, and no responsibility or liability is or will be accepted by BSI in relation to the adequacy, accuracy, completeness or reasonableness of this publication. All and any such responsibility and liability is expressly disclaimed to the full extent permitted by the law.

This publication is provided as is, and is to be used at the recipient’s own risk.

The recipient is advised to consider seeking professional guidance with respect to its use of this publication.

This publication is not intended to constitute a contract. Users are responsible for its correct application.

This publication is not to be regarded as a British Standard.

Compliance with a Published Document cannot confer immunity from legal obligations.

This Published Document was published under the authority of the Standards Policy and Strategy Committee on 31 August 2024.

FOREWORD

The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as "IEC Publication(s)"). Their preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with may participate in this preparatory work. International, governmental and non-governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely with the International Organization for Standardization (ISO) in accordance with conditions determined by agreement between the two organizations.
The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international consensus of opinion on the relevant subjects since each technical committee has representation from all interested IEC National Committees.
IEC Publications have the form of recommendations for international use and are accepted by IEC National Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any misinterpretation by any end user.
In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications transparently to the maximum extent possible in their national and regional publications. Any divergence between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter.
IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any services carried out by independent certification bodies.
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Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is indispensable for the correct application of this publication.
IEC draws attention to the possibility that the implementation of this document may involve the use of (a) patent(s). IEC takes no position concerning the evidence, validity or applicability of any claimed patent rights in respect thereof. As of the date of publication of this document, IEC had not received notice of (a) patent(s), which may be required to implement this document. However, implementers are cautioned that this may not represent the latest information, which may be obtained from the patent database available at https://patents.iec.ch. IEC shall not be held responsible for identifying any or all such patent rights.

IEC TS 62607‑2‑6 has been prepared by IEC technical committee 113: Nanotechnology for electrotechnical products and systems. It is a Technical Specification.

The text of this Technical Specification is based on the following documents:

Full information on the voting for its approval can be found in the report on voting indicated in the above table.

The language used for the development of this Technical Specification is English.

This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available at https://www.iec.ch/members_experts/refdocs. The main document types developed by IEC are described in greater detail at www.iec.ch/publications.

A list of all parts in the IEC 62607 series, published under the general title Nanomanufacturing – Key control characteristics, can be found on the IEC website.

The committee has decided that the contents of this document will remain unchanged until the stability date indicated on the IEC website under webstore.iec.ch in the data related to the specific document. At this date, the document will be

reconfirmed,
withdrawn, or
revised.

IMPORTANT — The "colour inside" logo on the cover page of this document indicates that it contains colours which are considered to be useful for the correct understanding of its contents. Users should therefore print this document using a colour printer.

INTRODUCTION

Vertically-aligned carbon nanotubes (VACNTs) possess array structures, in which nanotubes are oriented in the perpendicular direction to a substrate surface. Chemical vapour deposition (CVD) is one of the common methods for the synthesis of VACNTs, where CNTs can be grown in the presence of metal catalysts, via thermal decomposition of hydrocarbon sources such as methane, ethylene, acetylene, ethanol, and so on. VACNTs are promising as thermal interface materials in electronics assembly owing to their high thermal conductivity, desirable mechanical properties, and good stability. Thermal transport properties in VACNT films really depend on their distribution and alignment behaviours of individual nanotubes, disorders such as defects and impurities.

Thermal diffusivity is one of the key parameters that govern thermal transport properties in solid materials. Flash method is a well-established, standard technique for measuring the thermal diffusivity. Originally, flash method was applicable to homogeneous monolithic (single layer) samples. In fact, some previous works reported thermal diffusivity measurements for self- standing VACNTs that were peeled off from the substrates after the CNT growth. However, VACNT films will be tightly connected to solid substrates in possible practical applications such as thermal interface materials. This means that flash method can not be simply applied to VACNT films grown on solid substrates. Hence, there is a need for new reliable protocols based on flash method for evaluating thermal diffusivity of VACNT films on solid substrates. This document specifies standardized protocols for measuring thermal diffusivity of VACNTs grown on solid substrates with flash method, where the specimen is a bilayer of the VACNT film and the substrate.

1 Scope

This part of IEC 62607 specifies a protocol for determining the key control characteristic

thermal diffusivity

for vertically-aligned carbon nanotube (VACNT) films grown on solid substrates by

flash method.

A light pulse from a flash lamp or a laser is irradiated onto the front surface (substrate side) of the VACNT film on solid substrates. Then, the temperature change of the other side of the specimen is monitored in real time after the pulse irradiation. The thermal diffusivity of the VACNT film can be analysed from the time variation of this temperature change.

This method is applicable for evaluating the thermal transport properties of the VACNT films that can be used as thermal interface materials in electronics assembly.

2 Normative references

3 Terms, definitions and abbreviated terms

3.1 Terms and definitions

3.2 Abbreviated terms

4 Measurement of thermal diffusivity of vertically-aligned carbon nanotubes on solid substrates with flash method

4.1 General

4.2 Measurement principle

4.3 Thickness and mass density measurement for VACNT film

4.4 Coating substrate surface

4.5 Incident light pulse

4.6 Temperature measurement at the rear surface of sample

4.7 Measurement environment

5 Data analysis

5.1 Bilayer analytical model

5.2 Evaluation of thermal diffusivity of VACNT film

6 Reporting

Bibliography

PD IEC TS 62607-2-6:2024

Nanomanufacturing. Key control characteristics - Carbon nanotube-related products. Thermal diffusivity of vertically-aligned carbon nanotubes: flash method

Current

Published:

31 Aug 2024