ASTM D1829-90(1999)

NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: D 1829 – 90 (Reapproved 1999)
Standard Test Method for
Electrical Resistance of Ceramic Materials at Elevated
Temperatures
This standard is issued under the fixed designation D 1829; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope indicate contamination of a part or material, as well as provide
design data for high-temperature insulating devices.
1.1 This test method covers two procedures for the deter-
mination of insulation resistance and volume resistivity of
5. Apparatus
ceramic insulating materials at elevated temperatures between
5.1 Resistance-Measurement Device— The resistance be-
100 and 500°C.
tween electrodes shall be measured with a suitable device
1.1.1 Procedure A is suitable for obtaining a curve of the
having the required sensitivity and accuracy (see Test Methods
resistance versus temperature characteristics of a single speci-
D 257).
men over a wide temperature range.
5.2 Heating Chamber—For heating the specimen, a suitable
1.1.2 Procedure B is more suitable for rapid testing of large
electric furnace shall be used. The construction of the furnace
numbers of specimens at a fixed temperature.
shall be such that the specimen is subjected to a uniform heat
1.2 These properties shall be determined in accordance with
application with a minimum of temperature fluctuation. An
Test Methods D 257, except that the special procedures de-
adequate muffle should be provided to shield the specimen
scribed in this method shall be used.
from direct radiation by the heating elements. This may be
1.3 The values stated in inch-pound units are to be regarded
made of a ceramic such as aluminum oxide or equivalent. A
as standard.
grounded metallic shield shall also be provided within the
1.4 This standard does not purport to address all of the
furnace, preferably of silver, stainless steel, or equivalent, to
safety concerns, if any, associated with its use. It is the
isolate electrically the specimen test circuit from the heating
responsibility of the user of this standard to establish appro-
elements.
priate safety and health practices and determine the applica-
5.3 Specimen Holder:
bility of regulatory limitations prior to use. Specific hazard
5.3.1 The specimen shall be mounted under sufficient pres-
statements are found in Section 7.
sure to make good contact between two electrode backing
2. Referenced Documents plates within the heating chamber. These backing plates and
their respective leads should be made of silver or an equivalent
2.1 ASTM Standards:
metal of high thermal conductivity and thermal stability.
D 257 Test Methods for D-C Resistance or Conductance of
2 Sufficient thickness, such as ⁄4 in. (20 mm), shall be used to
Insulating Materials
prevent warping and to provide heat equalization between the
D 1711 Terminology Relating to Electrical Insulation
specimen and the electrode backing plates. The contact faces
3. Terminology
should be smaller than the test specimen electrodes, and one
electrode backing plate shall be movable to allow insertion and
3.1 Definitions—The definitions used in this test method are
removal of the specimen.
in accordance with Terminology D 1711.
5.3.2 Bring the high voltage lead through a hole in the oven
4. Significance and Use
wall using a bushing or an insulated wire. The electrical
insulation of the wire or bushing must have a high insulation
4.1 The significance and use of insulation resistance and
resistance at the test temperature. Up to about 250°C, polytet-
volume resistivity measurements in general are discussed in
rafluoroethylene or high alumina content ceramics are found
Test Methods D 257. The influence of temperature is discussed
suitable. At higher temperatures, it may be necessary to use a
in Appendix X1 of Test Methods D 257.
rigid lead passed through a hole in the oven wall and mounted
4.2 Insulation resistance and volume resistivity data can
on insulated supports outside the oven so that the lead does not
contact the oven wall or any support within the oven. Even at
This test method is under the jurisdiction of ASTM Committee C-21 on
very high temperatures air provides adequate insulation resis-
Ceramic Whitewares and Related Products and is the direct responsibility of
tance.
Subcommittee C21.03 on Test Methods for Whiteware Properties.
Current edition approved July 27, 1990. Published September 1990. Originally
5.3.3 Bring the low voltage electrode out of the oven using
e1
published as D 1829 – 61 T. Last previous edition D 1829 – 90 (1994) .
the techniques described in 5.3.2. Guard the low voltage lead
Annual Book of ASTM Standards, Vol 10.01.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
D 1829
(see Test Methods D 257 and 8.4 of this test method). Shielded and dissipation factor measurements, the electrodes should be
leads insulated with polytetrafluoroethylene are available. If made to extend to the edge of the specimen. Refer to Test
the rigid leads are used, it is necessary to provide a suitable Methods D 257 for discussion of surface and edge conductance
guard in the insulation supports for the low voltage lead outside effects and precautions.
the oven.
8. Procedure
5.4 Temperature-Control Device:
8.1 Procedure A, Stepwise Heat:
5.4.1 The temperature of the specimen shall be measured
8.1.1 Mount the specimen tightly between the electrodes,
using a thermocouple mounted as close to the specimen as
within the heating chamber.
possible without causing any adverse electrical effects. A
8.1.2 Raise the temperature at a rate not exceeding 10°C/
suggested method is to mount it directly into the ground
min from each temperature to the next test temperature.
electrode near the center in a hole extending almost to the
8.1.3 Take readings at 25°C intervals, with large intervals
upper surface of the plate. If neither backing plate is grounded,
permitted if they provide sufficient accuracy for the specific
the thermocouple must be withdrawn during measurement.
requirement. Before each reading, allow the chamber and
5.4.2 A temperature-control system should be provided that
specimen to reach thermal equilibrium at the desired tempera-
can maintain chamber temperature to 65°C over the required
ture by soaking a sufficient length of time.
temperature range. A recommended method is to use two
8.2 Procedure B, Hot Insertion:
thermocouples, one in the chamber for control and a second for
8.2.1 Before measurement, bring the heating chamber to
actual specimen temperature readings using a precision poten-
thermal equilibrium at the desired test temperature.
tiometer.
8.2.2 Place the specimen in the chamber between the
6. Hazards
electrodes.
8.2.3 Allow sufficient time for the specimen and chamber to
6.1 Warning— Lethal voltages may be present during this
reach thermal equilibrium.
test. It is essential that the test apparatus, and all associated
8.2.4 Following the reading, remove the specimen and
equipment that may be electrically connected to it, be properly
insert the next specimen. The time to reach equilibrium can be
designed and installed for safe operation. Solidly ground all
reduced if t
...