1、Designation:D 1829 90(Reapproved 1999)Standard Test Method forElectrical Resistance of Ceramic Materials at ElevatedTemperatures1This standard is issued under the fixed designation D 1829;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revisi
2、on,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon(e)indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers two procedures for the deter-mination of insulation resistance and volume resistivi
3、ty ofceramic insulating materials at elevated temperatures between100 and 500C.1.1.1 Procedure A is suitable for obtaining a curve of theresistance versus temperature characteristics of a single speci-men over a wide temperature range.1.1.2 Procedure B is more suitable for rapid testing of largenumb
4、ers of specimens at a fixed temperature.1.2 These properties shall be determined in accordance withTest Methods D 257,except that the special procedures de-scribed in this method shall be used.1.3 The values stated in inch-pound units are to be regardedas standard.1.4 This standard does not purport
5、to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.Specific hazardstatements are found in Section 7.2.Re
6、ferenced Documents2.1 ASTM Standards:D 257 Test Methods for D-C Resistance or Conductance ofInsulating Materials2D 1711 Terminology Relating to Electrical Insulation23.Terminology3.1 DefinitionsThe definitions used in this test method arein accordance with Terminology D 1711.4.Significance and Use4.
7、1 The significance and use of insulation resistance andvolume resistivity measurements in general are discussed inTest Methods D 257.The influence of temperature is discussedin Appendix X1 of Test Methods D 257.4.2 Insulation resistance and volume resistivity data canindicate contamination of a part
8、 or material,as well as providedesign data for high-temperature insulating devices.5.Apparatus5.1 Resistance-Measurement Device The resistance be-tween electrodes shall be measured with a suitable devicehaving the required sensitivity and accuracy(see Test MethodsD 257).5.2 Heating ChamberFor heatin
9、g the specimen,a suitableelectric furnace shall be used.The construction of the furnaceshall be such that the specimen is subjected to a uniform heatapplication with a minimum of temperature fluctuation.Anadequate muffle should be provided to shield the specimenfrom direct radiation by the heating e
10、lements.This may bemade of a ceramic such as aluminum oxide or equivalent.Agrounded metallic shield shall also be provided within thefurnace,preferably of silver,stainless steel,or equivalent,toisolate electrically the specimen test circuit from the heatingelements.5.3 Specimen Holder:5.3.1 The spec
11、imen shall be mounted under sufficient pres-sure to make good contact between two electrode backingplates within the heating chamber.These backing plates andtheir respective leads should be made of silver or an equivalentmetal of high thermal conductivity and thermal stability.Sufficient thickness,s
12、uch as34in.(20 mm),shall be used toprevent warping and to provide heat equalization between thespecimen and the electrode backing plates.The contact facesshould be smaller than the test specimen electrodes,and oneelectrode backing plate shall be movable to allow insertion andremoval of the specimen.
13、5.3.2 Bring the high voltage lead through a hole in the ovenwall using a bushing or an insulated wire.The electricalinsulation of the wire or bushing must have a high insulationresistance at the test temperature.Up to about 250C,polytet-rafluoroethylene or high alumina content ceramics are foundsuit
14、able.At higher temperatures,it may be necessary to use arigid lead passed through a hole in the oven wall and mountedon insulated supports outside the oven so that the lead does notcontact the oven wall or any support within the oven.Even atvery high temperatures air provides adequate insulation res
15、is-tance.5.3.3 Bring the low voltage electrode out of the oven usingthe techniques described in 5.3.2.Guard the low voltage lead1This test method is under the jurisdiction of ASTM Committee C-21 onCeramic Whitewares and Related Products and is the direct responsibility ofSubcommittee C21.03 on Test
16、Methods for Whiteware Properties.Current edition approved July 27,1990.Published September 1990.Originallypublished as D 1829 61 T.Last previous edition D 1829 90(1994)e1.2Annual Book of ASTM Standards,Vol 10.01.1Copyright ASTM,100 Barr Harbor Drive,West Conshohocken,PA 19428-2959,United States.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.(see Test Methods D 257 and 8.4 of this tes