ASTM_C_863_-_00_2016.pdf

Designation:C86300(Reapproved 2016)Standard Test Method forEvaluating Oxidation Resistance of Silicon CarbideRefractories at Elevated Temperatures1This standard is issued under the fixed designation C863;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers the evaluation of the oxidationresistance of silicon carbide refractories at elevated tempera-tures in an atmosphere of steam.The steam is used toaccelerate the test.Oxidation resistance is the ability of thesilicon carbide(SiC)in the refractory to resist conversion tosilicon dioxide(SiO2)and its attendant crystalline growth.1.2 This standard does not purport 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.2.Referenced Documents2.1 ASTM Standards:2C20 Test Methods for Apparent Porosity,Water Absorption,Apparent Specific Gravity,and Bulk Density of BurnedRefractory Brick and Shapes by Boiling WaterC830 TestMethodsforApparentPorosity,LiquidAbsorption,Apparent Specific Gravity,and Bulk Densityof Refractory Shapes by Vacuum PressureC914 Test Method for Bulk Density and Volume of SolidRefractories by Wax Immersion3.Significance and Use3.1 The oxidation of silicon carbide refractories at elevatedtemperatures is an important consideration in the application ofthese refractories.The product of oxidation is amorphous silicaor cristobalite,depending upon the temperature at whichoxidation takes place.This oxide formation is associated withexpansion and degradation of strength.The quantity of watervapor in the atmosphere greatly affects the rate of oxidation.3.2 The test,which creates and measures the expansion,issuitable for guidance in product development and relativecomparison in application work where oxidation potential is ofconcern.The variability of the test is such that it is notrecommended for use as a referee test.4.Apparatus4.1 Heated ChamberThe chamber shall be muffled(Note1)to confine the atmosphere.The size of the chamber and theheat source are optional.The temperature capability within thechamber shall be at least 1200C(2190F)with an allowabledeviation of 615C(27F)measured across the hearth.NOTE1Silicon carbide refractory material is recommended for use asthe muffle but other suitable refractory materials may be used.4.2 InstrumentControl and record the temperature of thechamber by a suitable instrument capable of maintaining therequirements in 4.1.Recommended thermocouple location iswithin 1 in.(25 mm)of the top of the specimens and over thecenter of the same assemblage.5.Test Specimen5.1 Specimen SizeObtain a quarter-brick size from a229-mm(9-in.)straight by cutting the brick along planesparallel to both the 229 by 64-mm(9 by 212-in.)and the 114 by64-mm(412by 212-in.)faces.Alternative specimens may betile,165 by 114 by 22 mm(612by 412by78in.),or otherconvenient shapes.5.2 Three specimens are required for each set of conditions.6.Conditions6.1 AtmosphereSteam is passed into the chamber(4.1)atthe rate of 32 kg/m3(2 lb/ft3)of chamber volume per hour.Provisions should be made to uniformly distribute steam withinthe chamber.6.2 The standard test temperatures are as follows with newsamples used at each temperature.Each temperature consti-tutes a test.800C(1470F)900C(1650F)1000C(1830F)1100C(2010F)1200C(2190F)1This test method is under the jurisdiction of ASTM Committee C08 onRefractories and is the direct responsibility of Subcommittee C08.04 on ChemicalBehaviors.Current edition approved June 1,2016.Published June 2016.Originallyapproved in 1977.Last previous edition approved in 2010 as C863 00(2010).DOI:10.1520/C0863-00R16.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 The test temperature is selected on the basis of the specificneeds that relate to the environment in which the product is toserve.The use of at least the three test temperatures 900C,1000C,and 1100C is recommended when characterization ofthe product is desired.6.3 DurationHold at the specified temperature for 500 h.7.Procedure7.1 Measure the weight and volume of each specimen to60.1 g and 60.1 cm3,respectively,in accordance with TestMethods C20,C830,or C914,especially recommended forfriable samples.7.2 Place the specimens in the chamber and seal thechamber.Bring the chamber to the specified test temperatureand then introduce steam at t