1、Designation:D294302(Reapproved 2012)Standard Test Method forAluminum Scratch of 1,1,1-Trichloroethane to DetermineStability1This standard is issued under the fixed designation D2943;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the
2、 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 is a screening test method to determine if sufficientinhibitors are present in 1,1,1-trichloroethane to provi
3、de atleast minimal stability in the presence of aluminum.1.2 Solvent passing this test method may not be stable forall applications.1.3 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
4、 appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.A specific hazardstatement is given in Section 6.2.Summary of Test Method2.1 A cleaned,degreased,dry metal coupon of aluminumalloy is immersed in inhibited 1,1,1-trichloroethane andscrat
5、ched while in the solvent.After sufficient time has elapsedto allow any reaction to occur,the presence or absence ofbubbling,solvent discoloration,or dark resinous material isnoted.The 1,1,1-trichloroethane is sufficiently inhibited only ifnone of these conditions is observed.3.Significance and Use3
6、.1 The degradation of insufficiently stabilized 1,1,1-trichloroethane,in the presence of aluminum,results in theformation of hydrochloric acid and polymeric residue.Thus,ifsuch degradation is allowed to continue,the aluminum will becorroded and the 1,1,1-trichloroethane rendered unusable.Thepresence
7、 of free water invalidates this test method.3.2 This test method can be used to determine if 1,1,1-trichloroethane is sufficiently stabilized to inhibit reaction withaluminum or aluminum alloys.Solvent passing this testmethod still may not be stable for all applications.Consult aproducer for use app
8、lications.3.3 Aluminum should not be used as a material of construc-tion for pumps,tanks,pipelines,valves,spray equipment,orother handling equipment used for chlorinated solvents.Prop-erly stabilized halogenated solvents are,however,commonlyused in cleaning aluminum and other sensitive metals.4.Appa
9、ratus4.1 Aluminum Sheet Metal,designated ASTM Alloy 1100(UNS No.A91100),20.016 to 0.040 in.(0.4 to 1 mm)thick.4.2 Mild Steel Metal Object,such as an ice pick sharpenedto lead pencil-sized point.5.Preparation of Aluminum Coupon5.1 Degrease an aluminum coupon,1 by 1 in.,(2.5 by 2.5cm)by rinsing in a c
10、ommercial grade of solvent such asperchloroethylene,trichloroethylene,or 1,1,1-trichloroethane.Hand-sand both sides of the aluminum coupon lightly with afine emery cloth,and rinse the coupon again.The surfaceshould be bright and free of haze.6.Hazards6.1 This test method should be performed in a fum
11、e hood.Insufficiently inhibited solvent can react with aluminum toform hydrogen and hydrogen chloride gases.Solvent vaporsare also present.Their release to the atmosphere must beminimized.7.Procedure7.1 Conduct this test method at room temperature.Measure50 mL of inhibited 1,1,1-trichloroethane into
12、 a clean solvent-rinsed glass beaker.Place a freshly prepared aluminum couponin the solvent sample in a horizontal position on the bottom ofthe beaker.Scratch(Note 1)the top surface of the submergedaluminum coupon with a sharply pointed mild steel instrument.Make three scratches approximately equall
13、y spaced and 0.005in.(0.1 mm)deep in one direction.Then make three additionalscratches at right angles to the original three(Note 2).Observethe aluminum coupon after 10 min and again after 1 h haselapsed.In the event that continued decomposition occurs after1This test method is under the jurisdictio
14、n of ASTM Committee D26 onHalogenated Organic Solvents and Fire Extinguishing Agents and is the directresponsibility of Subcommittee D26.04 on Test Methods.Current edition approved March 1,2012.Published May 2012.Originallyapproved in 1971 as D294371 T.Last previous edition approved in 2007 as D2943
15、02(2007).DOI:10.1520/D2943-02R12.2Annual Book of ASTM Standards,Vol 02.02.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 1 h,add water to stop the reaction,remove the aluminumcoupon,and discard the solvent in a solvent container topreven
16、t evaporation.NOTE1The scratch should be a lateral scrape rather than a verticalperforation.NOTE2Scratches are to appear as follows:8.Report8.1 For each test method,report observations as follows:8.1.1 Passes/no reaction.8.1.2 Fails/the appearance of gas bubbles,color formation,or metal corrosion at the edge of the scratch marks are evidenceof failure to pass the test method.8.2 The solvent should be considered sufficiently stabilizedfor many uses in the presence of aluminum or aluminum alloyson