SIST EN 821-3:2005
(Main)Advanced technical ceramics - Monolithic ceramics. Thermo-physical properties - Part 3: Determination of specific heat capacity
Advanced technical ceramics - Monolithic ceramics. Thermo-physical properties - Part 3: Determination of specific heat capacity
This document specifies two methods for the determination of specific heat capacity of advanced monolithic technical ceramic materials based on drop calorimetry (Method A) and differential scanning calorimetry (DSC, Method B) over a temperature range from room temperature upwards, depending on the design of the equipment.
NOTE 1 The methods described apply in the case of test materials free from phase transformations, annealing effects or partial melting. If any such effect occurs in a material over the temperature range of the test, spurious results will be obtained unless the data are carefully analysed. In such cases it is usually necessary to conduct repeat tests at a number of temperatures close to the discontinuity, in order to estimate correctly its contribution to the apparent heat capacity.
NOTE 2 Care should be exercised in both methods over the selection of the cell or crucible material and in the selection of the test atmosphere, especially at high temperatures. Test pieces can react with the crucible or the atmosphere, leading to spurious results. In general, an awareness of such problems should be maintained at all times. Especially with regard to Method B, awareness should also be maintained of radiation effects at temperatures above 1000 °C, and of the reproducibility of the output signal.
Hochleistungskeramik - Monolithische Keramik - Thermophysikalische Eigenschaften - Teil 3: Bestimmung der spezifischen Wärmekapazität
Dieses Dokument legt zwei Verfahren zur Bestimmung der spezifischen Wärmekapazität monolithischer Hochleistungskeramik fest, die auf der Fallkalorimetrie (Verfahren A) und der dynamischen Differenz-Kalorimetrie (DDK, Verfahren B) beruhen; dabei werden Temperaturbereiche von Raumtemperatur an steigend bis zu einer gerätebedingten Endtemperatur abgedeckt.
ANMERKUNG 1 Die festgelegten Verfahren gelten für den Fall, dass die zu prüfenden Werkstoffe keine Phasenumwandlungen, keine Erholungseffekte oder partielle Aufschmelzungen durchmachen. Falls ein Werkstoff einen solchen Effekt im Temperaturbereich der Prüfung zeigt, werden falsche Ergebnisse erhalten, es sei denn, die Werte wurden sorgfältig analysiert. In solchen Fällen ist es üblicherweise notwendig, bei mehreren Temperaturen nahe der Transformationstemperatur Wiederholungsmessungen durchzuführen, um so exakt den Beitrag zu der scheinbaren Wärmekapazität abschätzen zu können.
ANMERKUNG 2 Die Art des Werkstoffes der Messzelle bzw. des Tiegels und die Art der Prüfatmosphäre sollten sachkundig festgelegt werden, insbesondere bei Hochtemperaturmessungen. Proben können sowohl mit dem Tiegel als auch der Atmosphäre reagieren, was zu falschen Ergebnissen führt. Im Allgemeinen sollte jederzeit mit solchen Problemen gerechnet werden. Besonders im Hinblick auf Verfahren B sollte bei Temperaturen über 1 000 °C die Aufmerksamkeit auf Strahlungseffekte und die Reproduzierbarkeit des Messsignals gelenkt werden.
Céramiques techniques avancées - Céramiques monolithiques. Propriétés thermophysiques - Partie 3 : Détermination de la chaleur spécifique
Sodobna tehnična keramika - Monolitna keramika - Termofizikalne lastnosti - 3. del: Ugotavljanje posebne toplotne kapacitete
General Information
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Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN 821-3:2005
01-maj-2005
1DGRPHãþD
SIST ENV 821-3:2000
6RGREQDWHKQLþQDNHUDPLND0RQROLWQDNHUDPLND7HUPRIL]LNDOQHODVWQRVWL
GHO 8JRWDYOMDQMHSRVHEQHWRSORWQHNDSDFLWHWH
Advanced technical ceramics - Monolithic ceramics. Thermo-physical properties - Part 3:
Determination of specific heat capacity
Hochleistungskeramik - Monolithische Keramik - Thermophysikalische Eigenschaften -
Teil 3: Bestimmung der spezifischen Wärmekapazität
Céramiques techniques avancées - Céramiques monolithiques. Propriétés
thermophysiques - Partie 3 : Détermination de la chaleur spécifique
Ta slovenski standard je istoveten z: EN 821-3:2005
ICS:
81.060.30 Sodobna keramika Advanced ceramics
SIST EN 821-3:2005 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN 821-3:2005
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SIST EN 821-3:2005
EUROPEAN STANDARD
EN 821-3
NORME EUROPÉENNE
EUROPÄISCHE NORM
January 2005
ICS 81.060.99 Supersedes ENV 821-3:1993
English version
Advanced technical ceramics - Monolithic ceramics. Thermo-
physical properties - Part 3: Determination of specific heat
capacity
Céramiques techniques avancées - Céramiques Hochleistungskeramik - Monolithische Keramik -
monolithiques. Propriétés thermophysiques - Partie 3 : Thermophysikalische Eigenschaften - Teil 3: Bestimmung
Détermination de la chaleur spécifique der spezifischen Wärmekapazität
This European Standard was approved by CEN on 9 December 2004.
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, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,
Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36 B-1050 Brussels
© 2005 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 821-3:2005: E
worldwide for CEN national Members.
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SIST EN 821-3:2005
EN 821-3:2005 (E)
Contents
Page
Foreword.3
1 Scope .4
2 Normative references .4
3 Terms and definitions .4
4 Method A – Drop calorimetry.5
5 Method B – Differential scanning calorimetry (DSC) .8
6 Report .10
Bibliography .18
2
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SIST EN 821-3:2005
EN 821-3:2005 (E)
Foreword
This document (EN 821-3:2005) has been prepared by Technical Committee CEN/TC 184 “Advanced
technical ceramics”, the secretariat of which is held by BSI.
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 August 2005, and conflicting national standards shall be withdrawn at
the latest by August 2005.
EN 821 Advanced technical ceramics — Monolithic ceramics - Thermo-physical properties consists of the
following parts:
Part 1: Determination of thermal expansion
Part 2: Determination of thermal diffusivity by the laser flash (or heat pulse) method
Part 3: Determination of specific heat capacity
This document supersedes ENV 821-3:1993
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland
and United Kingdom.
3
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SIST EN 821-3:2005
EN 821-3:2005 (E)
1 Scope
This document specifies two methods for the determination of specific heat capacity of advanced monolithic
technical ceramic materials based on drop calorimetry (Method A) and differential scanning calorimetry (DSC,
Method B) over a temperature range from room temperature upwards, depending on the design of the
equipment.
NOTE 1 The methods described apply in the case of test materials free from phase transformations, annealing effects or
partial melting. If any such effect occurs in a material over the temperature range of the test, spurious results will be
obtained unless the data are carefully analysed. In such cases it is usually necessary to conduct repeat tests at a number
of temperatures close to the discontinuity, in order to estimate correctly its contribution to the apparent heat capacity.
NOTE 2 Care should be exercised in both methods over the selection of the cell or crucible material and in the
selection of the test atmosphere, especially at high temperatures. Test pieces can react with the crucible or the
atmosphere, leading to spurious results. In general, an awareness of such problems should be maintained at all times.
Especially with regard to Method B, awareness should also be maintained of radiation effects at temperatures above
1000 °C, and of the reproducibility of the output signal.
2 Normative references
The 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 (including any amendments) applies.
EN 60584-1, Thermocouples Part 1: Reference tables
EN 60584-2, Thermocouples Part 2: Tolerances
EN ISO/IEC 17025: 2000, General requirements for the competence of testing and calibration laboratories
(ISO/IEC 17025:1999)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
enthalpy, ∆H
heat content of an object in joules released or absorbed as a result of a temperature change.
3.2
specific heat capacity, c
p
amount of heat (q) in joules required to raise the temperature of a 1 g mass by 1 °C at temperature T at
constant pressure, in accordance with the equation
dq 1 dQ
= = (1)
c
p
dT m dT
where Q is the total heat required for a test piece of mass m.
4
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SIST EN 821-3:2005
EN 821-3:2005 (E)
3.3
mean specific heat capacity,
c
p
amount of heat (q) required to raise the temperature of a 1 g mass from temperature T to temperature T ,
1 2
divided by the temperature interval in degrees Celsius at constant pressure, i.e:
q( → ) Q( → ) ∆H
T T T T
1 2 1 2
= = = (2)
c p
- m( - ) m( - )
T T T T T T
2 1 2 1 2 1
3.4
calorimeter
device for measuring the amount of heat input to or output from a test piece.
3.5
drop calorimeter
calorimeter into which a test piece at initially high temperature is dropped and allowed to cool, and the total
heat content (enthalpy) of the test piece is measured as a temperature rise or other parameter in the
calorimeter.
3.6
differential scanning calorimeter
device in which the difference in energy input into a test piece and into a calibrant may be measured as a
function of temperature while subjected to a temperature controlled heating or cooling schedule. This
difference is related to the difference in heat capacity between the test piece and the calibrant.
4 Method A – Drop calorimetry
4.1 General
This method may be used for measurements up to a temperature of 2000 °C.
4.2 Principle
A test piece, sealed in a crucible where necessary, is heated to the required temperature suspended in a
vertical tube furnace positioned above a receiving calorimeter. A shutter prevents radiative heat from the
furnace from reaching the calorimeter. The calorimeter may be any suitable device for recording the total
amount of heat extracted from the test piece to cool it to the ambient temperature. The test piece, or crucible
containing the test piece, is allowed to drop through the shutter into the calorimeter. The response of the
calorimeter is monitored continuously. The output curve is analysed, incorporating the calibrated response of
the calorimeter and of the crucible if used, and the mean specific heat capacity is calculated.
NOTE Using several determinations of over different temperature ranges, the true c at temperature T can be
p p
estimated by curve-fitting routines (see 4.6).
Adherence to the procedure described below should provide results with an accuracy of better than 5% up to
1600 °C.
5
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SIST EN 821-3:2005
EN 821-3:2005 (E)
4.3 Apparatus
4.3.1 A vertical tube furnace of suitable design and maximum temperature capability is controlled by a
Pt/Pt 13 % Rh or Pt/Pt 10 % Rh thermocouple (for temperatures to 1650 °C) or other suitable type (for higher
temperatures) connected to a temperature controller capable of maintaining a given temperature to a
constancy of ± 1 °C. The temperature profile of the furnace shall be such as to contain a section of at least
twice the length of the crucible or test piece which is at constant temperature to within ± 0,5 °C (see 4.4).
A capability for operating with an inert atmosphere is required for the testing of non-oxide materials at
elevated temperatures.
4.3.2 The calorimeter may comprise any suitable device for receiving the hot test piece and for recording
the total heat transmitted to it from the test piece. An example based on a massive copper block is shown in
Figure 1. Other examples include an ice calorimeter in which the heat transmitted is recorded as the melting of
ice through the volume decrease incurred, observed using a capillary level indicator.
NOTE A simple water immersion calorimeter is not recommended for initial test piece temperatures above 100 °C.
Whichever type is employed, it shall be capable of calibration using reference materials or a known amount of
electrical power. In the example of a massive copper block, the tapered central hole is designed to mate with
the crucible or test piece to provide intimate thermal contact. The block contains a resistance heater and a
platinum resistance thermometer. It is supported on three adjustable locating pins incorporating thermally
insulating sections.
4.3.3 The calorimeter is placed inside a vessel in a temperature-controlled environment, such as an oil bath
as shown in Figure 2. The temperature of the environment shall be constant to within ± 0,1 °C over periods of
15 min.
4.3.4 The test piece shall be either a solid test sample of size and shape appropriate to the calorimeter, or
shall comprise fragments or a powder. It may be either:
a) enclosed in a platinum crucible with a tight-fitting or sealed lid, with geometry suitable for making intimate
thermal contact with the calorimeter, and with the capability of being sealed and suspended by a platinum
wire (all samples); or
b) in a form capable of having a platinum suspension wire attached at its upper end (solid samples only).
NOTE The use of a crucible enables the test to be employed on powdered samples, which is especially
advantageous for calibration purposes using a reference powder.
4.3.5 There shall be an arrangement whereby either the crucible or the test piece (depending upon the
design and operation of the apparatus) suspended in the furnace may be dropped through a radiation screen,
such as a shutter mechanism timed to open for the passage of the test piece and to close after its passage.
NOTE This minimizes the heat flux directly radiated from the hot furnace to the calorimeter.
4.3.6 A balance is required to weigh the test piece to the nearest 0,001 g.
4.4 Temperature measurement and calibration
4.4.1 For furnace temperatures below 1650 °C, the initial temperature of the test piece in the furnace shall
be measured by a Pt/Pt 13 % Rh (Type R) or Pt/Pt 10 % Rh (Type S) thermocouple with a tolerance
conforming to EN 60584-2, allowing use of the reference tables in EN 60584-1, or alternatively calibrated in a
manner traceable to the International Temperature Scale.
For furnace temperatures above 1650 °C, an alternative thermocouple type shall be required.
6
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SIST EN 821-3:2005
EN 821-3:2005 (E)
A thermocouple shall be sited with its junction on the inside of the furnace tube in order to record furnace wall
temperature. A similar thermocouple shall be placed inside a platinum capsule or a dummy test piece. The
furnace wall temperature shall be allowed to equilibriate for at least 15 min. The capsule or dummy test piece
shall then be raised or lowered through the thermal centre of the furnace in steps of not more than 10 mm in
order to plot the temperature distribution. This procedure is used to establish the optimum position of the
capsule or test piece in the furnace and to calibrate the difference between capsule or test piece and the
furnace wall. This calibration is performed at a series of temperatures at intervals not exceeding 100 °C up to
the maximum furnace temperature, and is used as an indirect measure of initial test piece temperature.
4.4.2 The procedure for a massive copper block calorimeter or similar device in which a temperature rise is
recorded is as follows. The calorimeter temperature is measured using a platinum resistance thermometer
(PRT) connected into an a.c. bridge circuit, on the opposite arm of which is a matching standard resistor kept
at a known stabilized temperature ± 0,1 °C, which may conveniently be the temperature of the controlled
environment. In order to calibrate the calorimeter, a known electrical power is dissipated in the heating resistor
for a known time period, ∆t, determined either using a stopwatch or other calibrated timing device. The output
of the a.c. bridge is monitored continuously and the data are recorded at intervals of not less than 30 s. The
electrical input power is measured b
...
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