ASTM C539-84(2021)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: C539 − 84 (Reapproved 2021)
Standard Test Method for
Linear Thermal Expansion of Porcelain Enamel and Glaze
Frits and Ceramic Whiteware Materials by Interferometric
Method
This standard is issued under the fixed designation C539; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 4. Apparatus
4.1 Sample Preparation Equipment:
1.1 This test method covers the interferometric determina-
4.1.1 Glazed Porcelain Crucible, No. 0.
tion of linear thermal expansion of premelted frits (porcelain
4.1.2 Fireclay Crucible, 102 mm (4 in.) in diameter.
enamel and glaze) and fired ceramic whiteware materials at
4.1.3 Rotating Abrasive Grinding Wheel (a silicon carbide
temperatures lower than 1000 °C (1830 °F).
type is satisfactory).
1.2 This standard does not purport to address all of the
4.2 Micrometer Calipers, having a sensitivity such that the
safety concerns, if any, associated with its use. It is the
index can be read to 0.002 mm (0.0001 in.).
responsibility of the user of this standard to establish appro-
4.3 Measuring Apparatus, consisting of fused silica inter-
priate safety, health, and environmental practices and deter-
ferometer plates, viewing apparatus, an electric furnace and
mine the applicability of regulatory limitations prior to use.
control, potentiometer, pyrometer, and a suitable monochro-
1.3 This international standard was developed in accor-
matic light source of known wavelength.
dance with internationally recognized principles on standard-
4.3.1 Furnace—The furnace shall be a vertical electric tube
ization established in the Decision on Principles for the
furnace controlled by rheostat or other means so the heating
Development of International Standards, Guides and Recom-
rate of the furnace can be readily duplicated from room
mendations issued by the World Trade Organization Technical
temperature to 1000°C (1830°F). The heating rate shall not
Barriers to Trade (TBT) Committee.
exceed 3°C (5.5°F)/min.
4.3.2 Temperature Measuring Instrument— A calibrated
2. Referenced Documents
platinum versus platinum-rhodium thermocouple (or a
Chromel versus Alumel thermocouple if it is frequently cali-
2.1 ASTM Standards:
brated) in conjunction with a potentiometer shall be used. The
E289 Test Method for Linear Thermal Expansion of Rigid
potentiometer shall be capable of being read to 2°C (4°F) and
Solids with Interferometry
shall have automatic compensation for the temperature of the
reference junction, or the reference junction shall be held at
3. Significance and Use
0°C (32°F) by means of an ice bath.
3.1 This test method defines the thermal expansion of
5. Test Specimens
porcelain enamel and glaze frits by the interferometric method.
This determination is critical in avoiding crazing (cracking) of
5.1 For frit samples, three test specimens shall be prepared
these glass coatings due to mismatching of the thermal
as follows:
expansion between the coating and substrate materials.
5.1.1 Fill a No. 0 glazed porcelain crucible with frit, place
the filled crucible inside a 102-mm (4-in.) diameter fireclay
crucible partly filled with silica, and work the small crucible
This test method is under the jurisdiction ofASTM Committee B08 on Metallic
and Inorganic Coatings and is the direct responsibility of Subcommittee B08.12 on
Materials for Porcelain Enamel and Ceramic-Metal Systems. An example of suitable test equipment and an inferometric method may be
Current edition approved April 1, 2021. Published May 2021. Originally found in the paper by Merritt, G. E., “The Interference Method of Measuring
approvedin1964.Lastpreviouseditionapprovedin2016asC539 – 84(2016).DOI: Thermal Expansion,” Journal of Research, National Institute of Standards and
10.1520/C0539-84R21. Technology, Vol 10, No. 1, January 1933, p. 59 (RP 515).
For referenced ASTM standards, visit the ASTM website, www.astm.org, or A description of a permissible automatic fringe recording device may be found
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM in the paper by Saunders, J. B., “An Apparatus for Photographing Interference
Standards volume information, refer to the standard’s Document Summary page on Phenomenon,” Journal of Research, National Institute for Standards and
the ASTM website. Technology, Vol 35, No. 3, September 1945, p. 157 (RP 1668).
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C539 − 84 (2021)
down into the silica until approximately 75 % of the small 7. Procedure
crucible is below the level of the silica.
7.1 Assemble (outside the furnace) the three test pieces
5.1.2 Place the crucible assembly into a furnace at a
prepared as described in Section 5 between the two interfer-
temperaturehighenoughtojustmeltthemass.Holdfor15min
ometer plates as follows:
after the frit has reached the furnace temperature.
7.1.1 Place the plate with the one frosted side down within
the refractory specimen crucible.
5.1.3 Remove the crucible, rapidly transfer it to another
7.1.2 Place the three test pieces on this plate in an equilat-
furnace that is at the frit firing temperature, and cool in the
eral triangle.
furnace at a rate not to exceed 60 °C (110 °F)⁄h.
7.1.3 Lower the clear plate onto the test pieces keeping the
5.1.4 Break the small crucible open and break up the
mark or notch identifying the wedge side in the up position.
vitreous mass. Select six fragments from the interior of the
7.1.4 Set this assembly at a height comparable to that used
mass (to avoid side portions diluted by the ceramic crucible)
inside the furnace.
having minimum conical dimensions of 3 mm ( ⁄8 in.) at the
base and 6 mm ( ⁄4 in.) high. 7.2 Rotate the telescope and center it over the test specimen
assembly. Direct the monochromatic light source down the
5.2 For fired samples, break and select six samples having
tube. If four to eight fringes are present, the setup is correct. If
minimum conical dimensions of 3 mm ( ⁄8 in.) at the base and
fewer or more fringes are present, adjust the cone heights. In
6mm( ⁄4 in.) in height. For all samples, grind the base of the
some cases, mere tapping of the specimen assembly will
flatconesandcementtheflatconebasetotheflatendofaglass
produce the correct number of fringes. Carefully measure and
rod with heated sealing wax. Grind the piece to a finished cone
record the height of each cone. Upon achieving the proper
by rotating the rod while the piece is held against a rotating
number of fringes, place the refractory ring cover on the
abrasive wheel (a silicon carbide type is satisfactory).
crucible and recheck for fringes.
5.2.1 When a reasonably symmetrical cone with a rounded
7.3 Without rotating the crucible, gently lower it into the
tip is obtained, remove it from the rod by heating the wax or by
furnace and onto the bottom support so the thermocouple rests
pressure with the fingertips. Remove all sealing wax with a
at the bottom of the crucible. Cover the top of the furnace with
knife blade or abrasive paper.
a quartz plate.
5.2.2 The test cone height may be of the order of 4.8 mm
7.4 Rotate the telescope and check the fringe pattern. If
( ⁄16 in.). These bases must be smooth and flat. Use No. 0
excessive glare or poor contrast are present, adjust by moving
metallurgical paper to approach the desired figure and then use
the quartz cover, moving the light source, or releveling the
successively finer papers until the final reduction is made with
telescope.
a No. 3/0 paper.
NOTE 1—Removal of the telescope eyepiece should reveal a bright dot,
which is the true image. This must be in the field or no fringes will be
6. Calibration of Furnace
seen. If this bright dot of the true image is not seen when the eyepiece is
6.1 Using the following procedure, calibrate the furnace removed, a great deal of trial and error adjustment of the telescope tripod
must be made.Anumber of false images may also be present. These must
controls to obtain a heating rate of 3°
...