Bsi bs en 00725 3 1994 (1999)

www bzfxw com BRITISH STANDARD BS EN 725 3 1994 Advanced technical ceramics — Methods of test for ceramic powders — Part 3 Determination of the oxygen content of non oxides by thermal extraction with[.]

BRITISH STANDARD BS EN

725-3:1994

Advanced technical

ceramics — Methods of

test for ceramic

powders —

Part 3: Determination of the oxygen

content of non-oxides by thermal

extraction with a carrier gas

The European Standard EN 725-3:1994 has the status of a

British Standard

UDC 666.3-121:620.1:546.21

This British Standard, having

been prepared under the

direction of the Refractory

Products Standards Policy

Committee, was published

under the authority of the

Standards Board and comes

into effect on

15 May 1994

© BSI 11-1999

The following BSI references

relate to the work on this

standard:

Committee reference RPM/14

Draft for comment 92/39462 DC

ISBN 0 580 22393 0

Cooperating organizations

The European Committee for Standardization (CEN), under whose supervision this European Standard was prepared, comprises the national standards organizations of the following countries:

Austria Oesterreichisches Normungsinstitut Belgium Institut belge de normalisation Denmark Dansk Standardiseringsraad Finland Suomen Standardisoimisliito, r.y

France Association française de normalisation Germany Deutsches Institut für Normung e.V

Greece Hellenic Organization for Standardization Iceland Technological Institute of Iceland

Ireland National Standards Authority of Ireland Italy Ente Nazionale Italiano di Unificazione Luxembourg Inspection du Travail et des Mines Netherlands Nederlands Normalisatie-instituut Norway Norges Standardiseringsforbund Portugal Instituto Portuguès da Qualidade Spain Asociación Española de Normalización y Certificación Sweden Standardiseringskommissionen i Sverige

Switzerland Association suisse de normalisation United Kingdom British Standards Institution

Amendments issued since publication

Amd No Date Comments

BS EN 725-3:1994

Contents

Page

National annex NA (informative) Committees responsible Inside back cover

National foreword

This British Standard has been prepared under the direction of the Refractory Products Standards Policy Committee and is the English language version of

EN 725-3:1994, Advanced technical ceramics — Methods of test for ceramic

powders — Part 3: Determination of the oxygen content of non-oxides by thermal extraction with a carrier gas, published by the European Committee for

Electrotechnical Standardization (CEN)

EN 725-3 was produced as a result of international discussions in which the UK took an active part

A British Standard does not purport to include all the necessary provisions of a contract Users of British Standards are responsible for their correct application

Compliance with a British Standard does not of itself confer immunity from legal obligations.

Summary of pages

This document comprises a front cover, an inside front cover, pages i and ii, the EN title page, pages 2 to 6, an inside back cover and a back cover

This standard has been updated (see copyright date) and may have had amendments incorporated This will be indicated in the amendment table on the inside front cover

EUROPEAN STANDARD

NORME EUROPÉENNE

EUROPÄISCHE NORM

EN 725-3 January 1994

UDC 666.3-121:620.1:546.21

Descriptors: Ceramics, powdery materials, chemical analysis, determination of content, oxygen, extraction methods, reduction

methods, carbon monoxide

English version

Advanced technical ceramics — Methods of test for

ceramic powders — Part 3: Determination of the oxygen

content of non-oxides by thermal extraction with a carrier

gas

Céramiques techniques avancées — Méthodes

d’ essai pour poudres céramiques — Partie 3:

Détermination de la teneur en oxygène de

poudres non-oxydes par extraction à chaud

sous gaz porteur

Hochleistungskeramik — Prüfverfahren für keramische Pulver — Teil 3: Bestimmung des Sauerstoffgehaltes in Nichtoxid-Pulvern mittels Trägergasheißextraktion

This European Standard was approved by CEN on 1994-01-10 CEN members

are bound to comply with the CEN/CENELEC Internal Regulations which

stipulate the conditions for giving this European Standard the status of a

national standard without any alteration

Up-to-date lists and bibliographical references concerning such national

standards may be obtained on application to the Central Secretariat or to any

CEN member

This European Standard exists in three official versions (English, French,

German) A version in any other language made by translation under the

responsibility of a CEN member into its own language and notified to the

Central Secretariat has the same status as the official versions

CEN members are the national standards bodies of Austria, Belgium,

Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy,

Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and

United Kingdom

CEN

European Committee for Standardization Comité Européen de Normalisation Europäisches Komitee für Normung

Central Secretariat: rue de Stassart 36, B-1050 Brussels

© 1994 Copyright reserved to CEN members

Ref No EN 725-3:1994 E

Foreword

This European Standard has been prepared by

Technical Committee CEN/TC 184, Advanced

technical ceramics, the secretariat of which is held

by BSI

EN 725 consists of 11 Parts:

— Part 1: Determination of impurities in

alumina;

— Part 2: Determination of impurities in barium

titanate (ENV);

— Part 3: Determination of oxygen content of

non-oxides by thermal extraction with a carrier

gas;

— Part 4: Determination of oxygen content in

aluminium nitride by XRF analysis (ENV);

— Part 5: Determination of particle size

distribution;

— Part 6: Determination of the specific surface

area;

— Part 7: Determination of absolute density;

— Part 8: Determination of tapped bulk density;

— Part 9: Determination of untamped bulk

density;

— Part 10: Determination of compaction

properties;

— Part 11: Determination of densification on

natural sintering (ENV).

This document was submitted for the Formal Vote

and approved as a European Standard

This European Standard shall be given the status of

a national standard, either by publication of an

identical text or by endorsement, at the latest by

July 1994, and conflicting national standards shall

be withdrawn at the latest by July 1994

In accordance with the CEN/CENELEC Internal

Regulations, the following countries are bound to

implement this European Standard: Austria,

Belgium, Denmark, Finland, France, Germany,

Greece, Iceland, Ireland, Italy, Luxembourg,

Netherlands, Norway, Portugal, Spain, Sweden,

Switzerland and United Kingdom

Contents

Page

Annex A (informative) Guidance in the selection of test conditions 5

EN 725-3:1994

1 Scope

This Part of EN 725 describes a method for the

determination of the oxygen content of non-oxide

powders used for advanced technical ceramics,

using an inert carrier gas thermal extraction

method The method is suitable for oxygen contents

of less than 3 %

NOTE The limits of determination are given by the

manufacturers of the apparatus.

2 Principle

A test piece is heated in a graphite crucible at a high

temperature in a flow of an inert carrier gas Oxygen

in the sample is converted to oxides of carbon, which

are extracted and transformed to consist entirely of

either carbon monoxide or carbon dioxide This

volume is then determined by a suitable method of

gas analysis

NOTE Guidance on the selection of test conditions is given

in Annex A.

3 Apparatus

3.1 Graphite crucible, which is used as a carbon

source The crucible is capable of being electrically

heated by two electrodes, or by induction

3.2 Tin capsule, (optional) to contain the ceramic

powder sample

3.3 Nickel wire basket, (optional) for use as a fluxing

agent with certain powders such as aluminium

nitride

3.4 Gas analysis apparatus, based on one of the

following techniques:

a) volumetric analysis, for measurement of

carbon monoxide gas;

b) chromatography, for carbon monoxide;

c) thermal conductivity, for carbon monoxide and

carbon dioxide;

d) coulometric analysis, for carbon dioxide;

e) infrared absorption, for carbon dioxide

3.5 Furnace, normally capable of reaching at

least 2 500 °C operating in an inert gas atmosphere

(nitrogen, helium or argon)

NOTE Apparatus which does not achieve 2 500 °C may be used

for lower test temperatures, but 2 500 °C will be needed to give

the correct result for certain types of material.

4 Sample preparation

Take a sample of the dry powder, the quantity taken being based on the detection limit of the apparatus used for gas analysis and on the expected oxygen content of the powder

NOTE For example, for infrared absorption (see 3.4 e), samples

of 100 mg to 300 mg are required.

Use a scoop to handle the powder and place the sample either directly in the crucible or in the tin capsule If the capsule is used, squeeze it to expel air and then fold over the open end several times, weighing again after squeezing

5 Procedure

5.1 Heat the empty graphite crucible inside the furnace to a temperature greater than the temperature for analysis Record the flow of gas used in the furnace

NOTE 1 This is to prevent additional degassing of the crucible during the test run, which would produce errors.

NOTE 2 A recommendation for gas flow will normally be given

by the manufacturer of the instrument.

Cool to ambient temperature

5.2 Place the tin capsule and sample in the crucible Select a temperature which is high enough to dissociate the oxides to be determined

(see Annex A) Use the nickel wire basket (see 3.3) if

the preliminary tests suggest that it is necessary

Heat the furnace to the test temperature and record the temperature and the time at temperature

Collect the gas evolved and measure the amount,

using one of the analytical techniques listed in 3.4.

5.3 Repeat the procedure given in clause 4 and subclause 5.2 at least four times.

6 Blank determination

Carry out a blank determination for the apparatus whenever the gas supply or crucible batch is

changed Use the procedure given in clause 5 and

record the amount of gas evolved Use this blank value to calculate the results for the sample analysis

7 Calibration

Calibration shall be carried out preferably by using

a reference material of certified oxygen content to calibrate the furnace and gas analysis equipment,

using the procedure given in clause 5.

An alternative method is to use a sample of pure carbon monoxide or carbon dioxide gas to calibrate the gas analysis equipment, with a minimum of three results being recorded

8 Test report

The test report shall include the following

information:

a) the name of the test establishment;

b) the date of the test, a unique identification of

the report, the name and address of the customer,

a signatory of the report;

c) a reference to this European Standard,

i.e determined in accordance with EN 725-3;

d) a description of the test material

(manufacturer, type, batch or code number);

e) the type of analytical equipment used (see 3.4);

f) the method of calibration (see clause 7);

g) the purity of the carrier gas and gas used for calibration;

h) the mass of the samples and reference to

optional use of the tin capsule (see 3.2);

i) the test temperature;

j) the individual values of oxygen content, mean value and standard deviation:

k) comments about the test or test results

EN 725-3:1994

Annex A (informative)

Guidance in the selection of test

conditions

Because of the large variety of ceramic powders in

use and number of analytical techniques available,

it is not possible to specify test conditions (amount

of sample, temperature, gas flow rate, analytical

technique) that will be applicable to every

determination It is therefore recommended that the

optimum conditions for testing a material be

determined by preliminary tests This may be done

by carrying out successive tests on the same test

sample, increasing the reducing action until the

measured oxygen content reaches a maximum,

constant value Fluxing agents (see 3.3) may also be

used

When the test conditions have been established, a certified reference material of the same chemical type as the test sample should be tested to check these proposed conditions

BS EN 725-3:1994

© BSI 11-1999

National annex NA (informative)

Committees responsible

The United Kingdom participation in the preparation of this European Standard was entrusted by the Refractory Products Standards Policy Committee (RPM/-) to Technical Committee RPM/14 upon which the following bodies were represented:

British Ceramic Research Ltd

British Industrial Ceramic Manufacturers’ Association

British Steel Industry

Bureau of Analysed Samples Limited

China Clay Association

Ministry of Defence

Refractories Association of Great Britain

Society of Glass Technology

389 Chiswick High Road

London

W4 4AL

BSI is the independent national body responsible for preparing British Standards It presents the UK view on standards in Europe and at the international level It is incorporated by Royal Charter

Revisions

British Standards are updated by amendment or revision Users of British Standards should make sure that they possess the latest amendments or editions

It is the constant aim of BSI to improve the quality of our products and services

We would be grateful if anyone finding an inaccuracy or ambiguity while using this British Standard would inform the Secretary of the technical committee responsible, the identity of which can be found on the inside front cover

Tel: 020 8996 9000 Fax: 020 8996 7400

BSI offers members an individual updating service called PLUS which ensures that subscribers automatically receive the latest editions of standards

Buying standards

Orders for all BSI, international and foreign standards publications should be addressed to Customer Services Tel: 020 8996 9001 Fax: 020 8996 7001

In response to orders for international standards, it is BSI policy to supply the BSI implementation of those that have been published as British Standards, unless otherwise requested

Information on standards

BSI provides a wide range of information on national, European and international standards through its Library and its Technical Help to Exporters Service Various BSI electronic information services are also available which give details on all its products and services Contact the Information Centre

Tel: 020 8996 7111 Fax: 020 8996 7048

Subscribing members of BSI are kept up to date with standards developments and receive substantial discounts on the purchase price of standards For details

of these and other benefits contact Membership Administration

Tel: 020 8996 7002 Fax: 020 8996 7001

Copyright

Copyright subsists in all BSI publications BSI also holds the copyright, in the

UK, of the publications of the international standardization bodies Except as permitted under the Copyright, Designs and Patents Act 1988 no extract may be reproduced, stored in a retrieval system or transmitted in any form or by any means – electronic, photocopying, recording or otherwise – without prior written permission from BSI

This does not preclude the free use, in the course of implementing the standard,

of necessary details such as symbols, and size, type or grade designations If these details are to be used for any other purpose than implementation then the prior written permission of BSI must be obtained

If permission is granted, the terms may include royalty payments or a licensing agreement Details and advice can be obtained from the Copyright Manager Tel: 020 8996 7070