1、Designation: E 1559 09Standard Test Method forContamination Outgassing Characteristics of SpacecraftMaterials1This standard is issued under the fixed designation E 1559; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of l
2、ast 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 a technique for generating datato characterize the kinetics of the release of outgassingproduct
3、s from materials. This technique will determine boththe total mass flux evolved by a material when exposed to avacuum environment and the deposition of this flux on surfacesheld at various specified temperatures.1.2 This test method describes the test apparatus and relatedoperating procedures for ev
4、aluating the total mass flux that isevolved from a material being subjected to temperatures thatare between 298 and 398 K. Pressures external to the sampleeffusion cell are less than 7 3 103Pa (5 3 105torr).Deposition rates are measured during material outgassing tests.A test procedure for collectin
5、g data and a test method forprocessing and presenting the collected data are included.1.3 This test method can be used to produce the datanecessary to support mathematical models used for the predic-tion of molecular contaminant generation, migration, anddeposition.1.4 All types of organic, polymeri
6、c, and inorganic materialscan be tested. These include polymer potting compounds,foams, elastomers, films, tapes, insulations, shrink tubing,adhesives, coatings, fabrics, tie cords, and lubricants.1.5 There are two test methods in this standard. Test MethodA uses standardized specimen and collector
7、temperatures. TestMethod B allows the flexibility of user-specified specimen andcollector temperatures, material and test geometry, and user-specified QCMs.1.6 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.7 This standard d
8、oes 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 St
9、andards:2E 595 Test Method for Total Mass Loss and CollectedVolatile Condensable Materials from Outgassing in aVacuum Environment2.2 Military Standard:MIL-P-27401D Propellant Pressurizing Agent, Nitrogen32.3 Other Standard:SMC-TR-9528 Non-Volatile Residue Solvent Replace-ment, Report No. TR95 (5448)
10、-143. Terminology3.1 Definitions:3.1.1 AT cut crystal, na quartz crystal orientation thatminimizes the temperature coefficient (frequency change ver-sus temperature) over a wide range of temperature.3.1.2 azeotropic mixture, na solution of two or moreliquids, the composition of which does not change
11、 upondistillation. Also known as azeotrope.3.1.3 collected volatile condensable material, CVCM,n(from Test Method E 595). The quantity of outgassedmatter from a test specimen that condenses on a collectormaintained at a specific constant temperature for a specifiedtime and measured before and after
12、the test outside thechamber.3.1.3.1 DiscussionCVCM is specific to Test MethodE 595 and is calculated from the condensate mass determinedfrom the difference in mass of the collector plate before andafter the test in a controlled laboratory environment. CVCM isexpressed as a percentage of the initial
13、specimen mass. Theview factor is not considered; so all the VCM outgassing fromthe sample may not be collected. Care should be used incomparing the CVCM from Test Method E 595 with VCMfrom this test method.1This test method is under the jurisdiction of ASTM Committee E21 on SpaceSimulation and Appli
14、cations of Space Technology and is the direct responsibility ofSubcommittee E21.05 on Contamination.Current edition approved April 1, 2009. Published May 2009. Originallyapproved in 1993. Last previous edition approved in 2003 as E 1559 03.2For referenced ASTM standards, visit the ASTM website, www.
15、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.3Available from Standardization Documents Order Desk, Bldg. 4 Section D, 700Robbins Ave., Philadelphia, PA 19111-5094, At
16、tn: NPODS.4Available from The Aerospace Corporation, P.O. Box 92957, Los Angeles, CA900092957, http:/www.aero.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.1.4 differential scanning calorimetry, DSC, na tech-nique in which th
17、e difference in energy inputs into a substanceand a reference material is measured as a function of tempera-ture while the substance and reference material are subjected toa controlled-temperature program.3.1.5 effusion cell, na container, placed in a vacuum, inwhich a sample of material can be plac
18、ed and heated to somespecified temperature.3.1.5.1 DiscussionThe container has a cylindrical orificeat one end so that evolving gases exit the cell in a controlledmanner. The effusion cell dimensions and orifice size arespecified such that there is free molecular flow of the evolvinggasses and a pre
19、dictable molecular flux from the orifice.3.1.6 mass flux, nthe mass of molecular flux.3.1.7 molecular flux (moleculescm2s1), nthe numberof gas molecules crossing a specified plane in unit time per unitarea.3.1.8 nonvolatile residue, NVR, nthe quantity of residualmolecular and particulate matter rema
20、ining following thefiltration of a solvent containing contaminants and evaporationof the solvent at a specified temperature.3.1.9 outgassing, nthe evolution of gas from a material,usually in a vacuum. Outgassing also occurs in a higherpressure environment.3.1.10 quartz crystal microbalance, QCM, na
21、device formeasuring small quantities of mass using the properties of aquartz crystal oscillator.3.1.10.1 DiscussionThe resonant frequency of a quartzcrystal oscillator is inversely proportional to the thickness ofthe crystal. When the mass of a uniform deposit is smallrelative to the mass of the cry
22、stal, the change in frequency isproportional to the mass of the deposit.3.1.11 QCM thermogravimetric analysis, QTGA, na tech-nique in which a QCM is heated at a constant rate to removea collected deposit.3.1.11.1 DiscussionThis is performed to determine theevaporation characteristics of the species
23、in the deposit. Themass of the deposit on the QCM is recorded as a function oftime or temperature.3.1.12 residual gas analyzer, RGA, na mass spectrometermounted inside or attached to a vacuum chamber.3.1.12.1 DiscussionRGA can be used for identifyinggases in the vacuum chamber.3.1.13 total mass flux
24、 (gcm2s1), nthe summation of themass from all molecular species crossing a specified plane inunit time per unit area.3.1.14 total mass loss, TML, ntotal mass of materialoutgassed from a test specimen that is maintained at a specifiedconstant temperature and operating pressure for a specifiedtime and
25、 measured within the test chamber. TML is expressedas a percentage of the initial specimen mass. In addition, TMLcan be normalized with respect to the sample surface area andbe expresed as g/cm2.3.1.14.1 in-situ TML, ncalculated from the mass depos-ited on a cryogenically cooled QCM and the view fac
26、tor fromthe effusion cell orifice to the QCM.3.1.14.2 DiscussionIn-situ TML is a function of theoutgassing test time and is expressed as a percentage of theinitial specimen mass. This is not necessarily the same as theTML determined by Test Method E 595.3.1.14.3 ex-situ TML, ntotal mass of material
27、outgassedfrom a test specimen that is maintained at a specified constanttemperature and operating pressure for a specified time andmeasured outside the test chamber.3.1.14.4 DiscussionEx-situ TML is calculated from themass of the specimen as measured before and after the test ina controlled laborato
28、ry environment and is expressed as apercentage of the initial specimen mass. (From Test MethodE 595.)3.1.15 total outgassing rate, nthe net rate of mass lossfrom a material sample as a result of outgassing. Totaloutgassing rate can be normalized per unit sample surface areaand expressed as gcm2s1or
29、it can be normalized per unitinitial sample mass and expressed as gg1s1.3.1.16 volatile condensable material, VCM, nthe matterthat outgasses from a material and condenses on a collectorsurface that is at a specified temperature.3.1.16.1 DiscussionFor this test method, this is the quan-tity of outgas
30、sed matter from a test specimen that condenses onsurfaces maintained at QT2 or QT3. The VCM is calculatedfrom the mass deposited on QCM2 or QCM3 and the viewfactor from the effusion cell orifice to the QCMs. VCM is afunction of the outgassing test time and is expressed as apercentage of the initial
31、specimen mass. In addition, VCM canbe normalized with respect to the sample surface area and beexpressed as g/cm2. This is not the same as CVCM asdetermined by Test Method E 595 (see 3.1.3).3.2 Acronyms:Acronyms:3.2.1 GN2, ngaseous nitrogen.3.2.2 LN2, nliquid nitrogen.3.2.3 MAPTIS, nMaterials and Pr
32、ocess Technical Infor-mation Service.3.3 Definitions of Terms Specific to This Standard:3.3.1 QCM1the QCM that is operating at the temperatureTQ1 (cryogenic) for measuring the total outgassing rate.3.3.2 QCM2 and QCM3the QCMs that are operating attemperatures TQ2 and TQ3 for the measurement of thede
33、position of outgassing matter.4. Summary of Test Method4.1 The test apparatus described in this test method isdesigned to measure outgassing rate data that can be used todevelop kinetic expressions for use in models that predict theevolution of molecular contaminants and the migration anddeposition
34、of these contaminants on spacecraft surfaces. Ma-terials that contain volatile species that will be outgassed underthe temperature and vacuum conditions of this test method canbe characterized. The quartz crystal microbalances used in thistest method provide a sensitive technique for measuring verys
35、mall quantities of deposited mass. In addition to providingdata for kinetic expressions, the reduced data can be used tocompare the outgassing behavior of different materials formaterial selection purposes.4.2 There are two test methods in this standard. Test MethodAis the standard procedure using p
36、rescribed configurations andE1559092temperatures. Test Method B allows for the use of spacecraftsystem specific temperatures, configurations, and QCM collec-tor surface finishes.4.3 The measurements are made by placing the materialsample in an effusion cell so that the outgassing flux leavingthe cel
37、l orifice will impinge on three QCMs which are arrangedto view the orifice.Afourth QCM is optional. The effusion cellis held at a constant temperature in the high vacuum chamberand has a small orifice directed at the QCMs. The QCMs arecontrolled to selected temperatures. The total outgassing rate is
38、determined from the collection rate on a cryocooled QCM. Atthe end of the isothermal test, the QCMs are heated in acontrolled manner to determine the evaporation characteristicsof the deposits.4.4 The effusion cell is loaded from the vacuum interlockchamber to the main test chamber and is positioned
39、 at a fixeddistance and angle with respect to the QCM surfaces. Theeffusion cell is temperature controlled to provide constant anduniform heating of the sample. The vacuum interlock chamberis a device that enables the expedient introduction of the testsample into the high vacuum of the main test cha
40、mber. Use ofthe interlock chamber to load and unload samples prevents lossof vacuum in the main chamber and diminishes the need topump it down before each test.4.5 The QCM collection method for measuring the totaloutgassing rate from a sample is an indirect technique. Ratherthan directly measuring s
41、ample mass loss, the basic measure-ment is the fraction of the flux that condenses on the cryogeni-cally cooled QCM collector at a point in the outgassing flowfield. That point in the flow field is defined as the geometriclocation of the QCM relative to the effusion cell orifice, whichis at a fixed
42、location. To determine the rate of sample mass lossfrom the rate of QCM collection, the view factor from theQCM to the effusion cell orifice and the angular distribution offlux leaving the orifice must be determined. This relationshipcan be calculated from the apparatus geometry and the effusioncell
43、 orifice dimensions.4.6 AQCM thermogravimetric analysis (QTGA) test is alsoincluded in the procedure. This technique heats the QCMs at aconstant rate to measure evaporation characteristics of thedeposits collected on the QCMs. The QTGA also provides aneffective means to clean the QCM surfaces before
44、 subsequenttests.4.7 It is critical to the posttest analysis that the materialsample be completely described and specified, so that theoutgassing characteristics can be applied to the material whenused on a spacecraft. It is also necessary so that any materialsample can be properly compared with tha
45、t of other samples.The outgassing rate of the material will, in general, bedetermined by its composition, processing history, and envi-ronmental conditioning before the test.All test sample process-ing should be representative of normal material processing andusage. All materials are environmentally
46、 conditioned to speci-fied conditions. However, samples may be subjected to envi-ronmental conditions that are expected during actual use. Testsample processing and conditioning history shall be included inthe test report.4.8 Because outgassing of all materials is, to some extent,diffusion rate cont
47、rolled, the outgassing rate of a test sampledepends on the distance from the sample interior to a freesurface. Hence, the geometry of a test sample must becontrolled in a specified manner to permit meaningful inter-pretation of the data. When possible, the sample geometryshould be in the specified c
48、onfiguration to simplify modeling.However, the material sample can be made with the samegeometry as it would have in an actual application.5. Test Apparatus5.1 DescriptionThe test apparatus consists of four mainsubsystems: a vacuum chamber, a temperature control system,internal configuration, and a
49、data acquisition system. Fig. 1 isa schematic of the systems, and Fig. 2 shows the vacuumchamber and internal configuration.5.2 Vacuum ChamberThe principal components of thevacuum chamber are the main test chamber, the vacuuminterlock chamber, and cryogenic shrouds (for example, LN2).A high-vacuum gate valve is used to isolate the main testchamber from the interlock chamber. This allows the effusioncell to be withdrawn or inserted into the main chamber withoutthe loss of high vacuum in the main chamber. High-vacuumelectrical and
