1、 CHECK THE MASTER LIST VERIFY THAT THIS IS THE CORRECT VERSION BEFORE USE MSFC-HDBK-3575 National Aeronautics and BASELINE Space Administration EFFECTIVE DATE: September 16, 2009 George C. Marshall Space Flight Center Marshall Space Flight Center, Alabama 35812 MULTIPROGRAM/PROJECT COMMON-USE DOCUME
2、NT Outgassing Rate Measurements for the Screening of Nonmetallic Materials DRAFT NO. 1 Approved for Public Release; Distribution Unlimited Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Multiprogram/Project Common-Use Document EM50 Title: Outgassing
3、 Rate Measurements for the Screening of Nonmetallic Materials Document No.: MSFC-HDBK-3575 Revision: Baseline Effective Date: September 16, 2009 Page 2 of 22 Pages CHECK THE MASTER LIST VERIFY THAT THIS IS THE CORRECT VERSION BEFORE USE DOCUMENT HISTORY LOG Status (Baseline/ Revision/ Canceled) Docu
4、ment Revision Effective Date Description Baseline 09/16/09 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Multiprogram/Project Common-Use Document EM50 Title: Outgassing Rate Measurements for the Screening of Nonmetallic Materials Document No.: MSFC
5、-HDBK-3575 Revision: Baseline Effective Date: September 16, 2009 Page 3 of 22 Pages CHECK THE MASTER LIST VERIFY THAT THIS IS THE CORRECT VERSION BEFORE USE FOREWORD This handbook is published by the National Aeronautics and Space Administration (NASA) to describe a processes and methodology by whic
6、h the rate of outgassing of nonmetallic materials can be measured. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Multiprogram/Project Common-Use Document EM50 Title: Outgassing Rate Measurements for the Screening of Nonmetallic Materials Document N
7、o.: MSFC-HDBK-3575 Revision: Baseline Effective Date: September 16, 2009 Page 4 of 22 Pages CHECK THE MASTER LIST VERIFY THAT THIS IS THE CORRECT VERSION BEFORE USE TABLE OF CONTENTS USECTIONU UPAGE DOCUMENT HISTORY LOG 2 FOREWORD . 3 1. SCOPE 6 1.1 Purpose . 6 1.2 Applicability 6 2. APPLICABLE DOCU
8、MENTS 8 2.1 General . 8 2.2 Government Documents . 8 2.3 Non-Government Documents . 8 3. MEASUREMENT METHODOLOGY . 8 3.1 UThe Outgassing Measurement 8 3.1.1 Measurement Limit . 8 3.1.2 The Temperature of the Source or Emitting Surface 8 3.1.3 Vacuum Chamber Pressure . 8 3.1.4 Mean Free Path . 8 3.1.
9、5 The Temperature of the Deposition Surface 9 3.1.6 Quartz Crystal Microbalance . 10 3.1.7 Cryogenic Shroud . 10 3.1.8 The Disposition Process . 11 3.2 Analysis 11 3.2.1 Conversion of Frequency to Mass 11 3.2.2 View Factor . 12 3.2.3 Sample Surface Area . 12 3.2.4 Source Term 12 3.2.5 Configurationa
10、l Analysis . 13 3.2.7 Determining ASTM E-595 %TML and %CVCM from Deposition Rate Measurements . 13 3.3 Operations 13 3.3.1 Chamber Background Measurement 13 3.3.2 Order of Measurements . 14 3.3.3 Measurement Duration 14 3.3.4 Deposition Surface Regeneration . 14 3.3.5 Thickness of a Material Deposit
11、ed on Contamination Sensitive Surfaces. 14 3.3.6 Material Acceptance Criteria 15 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Multiprogram/Project Common-Use Document EM50 Title: Outgassing Rate Measurements for the Screening of Nonmetallic Materi
12、als Document No.: MSFC-HDBK-3575 Revision: Baseline Effective Date: September 16, 2009 Page 5 of 22 Pages CHECK THE MASTER LIST VERIFY THAT THIS IS THE CORRECT VERSION BEFORE USE TABLE OF CONTENTS (Continued) USECTIONU UPAGE 3.3.7 Identification of Candidate Samples 16 3.3.8 Materials with High Outg
13、assing Rates . 16 3.3.9 Documentation . 17 4. GUIDANCE . 17 4.1 Reference Documents . 17 4.2 Key Word Listing . 17 4.3 Definitions . 17 Appendix A. Acronyms and Definitions . 19 Appendix B. Calculation of the Dwell Time of Contaminants on Surfaces 20 Appendix C. Calculation of the Clausing Factor fo
14、r an Orifice or Short Tube 21 UList of Figures UFigureU UPage 1 Measurement Process 7 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Multiprogram/Project Common-Use Document EM50 Title: Outgassing Rate Measurements for the Screening of Nonmetallic M
15、aterials Document No.: MSFC-HDBK-3575 Revision: Baseline Effective Date: September 16, 2009 Page 6 of 22 Pages CHECK THE MASTER LIST VERIFY THAT THIS IS THE CORRECT VERSION BEFORE USE 1. SCOPE 1.1 Purpose. The purpose of this handbook is to present a methodology for the systematic screening of nonme
16、tallic materials with a line of sight to an optical surface, thermal control surface, or other contamination sensitive surfaces in a vacuum environment. The outgassing measurements made using the methods described here will support configurational analysis of the release of molecular contamination f
17、rom the surface of a material and facilitate the prediction of the deposition of condensable materials on one or more adjacent surfaces. 1.2 UApplicability. UThis handbook is applicable to the test methodology used to evaluate the outgassing of nonmetallic materials used adjacent to contamination se
18、nsitive surfaces. This methodology is based on the American Society for Testing and Materials (ASTM), Standard Test Method for Contamination Outgassing Characteristics of Spacecraft Materials, Method E-1559, and describes methodology by which the outgassing source terms (rates) for nonmetallic mater
19、ials should be measured. This measurement differs from the measurement described in the ASTM Standard Test Method for Total Mass Loss and Collected Volatile Condensable Materials from Outgassing in a Vacuum Environment (Method E-595) which is a less complex outgassing measurement; possibly an altern
20、ative to the E-1559 measurement. The outgassing rate data obtained from the E-1559 measurement will support configurational analysis of the emittance and deposition of contaminants while the data obtained from the E-595 measurement will not. (See Figure 1.) 1.3 The selection of either measurement is
21、 a Program/Project decision and should take into account both the duration that a contamination-sensitive surface will be exposed to the outgassing material and the amount of volatile condensable materials (Vims) that can be deposited on a contamination-sensitive surface before the performance of th
22、e surface is degraded and/or no longer functional. In addition to deciding which measurement is the correct measurement to meet Program/Project needs, the Program/Project should identify a person or office to act as the Technical Authority. The Technical Authority will be charged with defining the c
23、riteria for the outgassing rate measurement as guidance to the technical community supporting the Program/Project. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Multiprogram/Project Common-Use Document EM50 Title: Outgassing Rate Measurements for t
24、he Screening of Nonmetallic Materials Document No.: MSFC-HDBK-3575 Revision: Baseline Effective Date: September 16, 2009 Page 7 of 22 Pages CHECK THE MASTER LIST VERIFY THAT THIS IS THE CORRECT VERSION BEFORE USE Figure 1. UMeasurement Process 1.4 This handbook may be cited in contract, Program/Proj
25、ect, and other Agency documents as a technical reference for guidance. Except where noted as mandatory, individual provisions of this reference may be tailored (i.e., modified or deleted) by contract or Program/Project direction to meet specific Program/Project needs and constraints. Tailoring shall
26、 be formally documented and approved as part of Program/Project Materials and Processes oversight. Application Temperature Predicted Deposition Surface Temperature Test Method Selection ASTM E-595 Chamber Background Measurement ASTM E-1559 Material Baked Out/ Additional Processing Measurement Deposi
27、tion Criteria Configurational Modeling Acceptable Material for Application General Materials Screening Support of Configurational Analysis Select Another Material Pass Fail Measurement Process - Outgassing Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-
28、,-,-Multiprogram/Project Common-Use Document EM50 Title: Outgassing Rate Measurements for the Screening of Nonmetallic Materials Document No.: MSFC-HDBK-3575 Revision: Baseline Effective Date: September 16, 2009 Page 8 of 22 Pages CHECK THE MASTER LIST VERIFY THAT THIS IS THE CORRECT VERSION BEFORE
29、USE 2. APPLICABLE DOCUMENTS 2.1 UGeneral. UThe documents listed in this section contain information that supplements the measurement methodology presented in this handbook. The latest issuances of cited documents should be used unless otherwise approved by the assigned Technical Authority. 2.2 UGove
30、rnment Documents. None 2.3 UNon-Government Documents. ASTM Method E-595 Standard Test Method for Total Mass Loss and Collected Volatile Condensable Materials from Outgassing in a Vacuum Environment ASTM Method E-1559 Standard Test Method for Contamination Outgassing Characteristics of Spacecraft Mat
31、erials 3. MEASUREMENT METHODOLOGY The outgassing process is simply the emittance or sublimation of molecular species from a surface, in a vacuum environment, and the subsequent condensation of some portion of the emitted species on a second surface. The outgassing measurement provides a method to qu
32、antify the transfer of material between the surfaces. 3.1 UThe Outgassing Measurement.U The purpose of this measurement is to determine an outgassing source term for nonmetallic materials, a potential source of condensable molecular contaminants, which could condense (deposit) on contamination-sensi
33、tive surfaces. The measurement should be made under controlled laboratory conditions in order to provide quality data on which Program/Project material selection decisions can be based. 3.1.1 UMeasurement LimitU. The deposition of molecular contaminants, at deposition rates approaching 5 x 10 P-15P
34、grams/cmP2P-s, can be easily be measured using a quartz crystal microbalance. However, the measurement parameters must be tightly controlled for the measurement to be accurate and for the measured outgassing rates to be useful as input for comput er simulations (configurational modeling) of the depo
35、sition process. The maximum deposition rate typically falls between 10 P-7P grams/cmP2P-s and 10 P-9P grams/cmP2P-s, varying with the quartz crystal microbalance being used for the measurement and its mass capacity. Provided by IHSNot for ResaleNo reproduction or networking permitted without license
36、 from IHS-,-,-Multiprogram/Project Common-Use Document EM50 Title: Outgassing Rate Measurements for the Screening of Nonmetallic Materials Document No.: MSFC-HDBK-3575 Revision: Baseline Effective Date: September 16, 2009 Page 9 of 22 Pages CHECK THE MASTER LIST VERIFY THAT THIS IS THE CORRECT VERSI
37、ON BEFORE USE 3.1.2 UThe Temperature of the Source or Emitting SurfaceU. The source temperature is typically one of the measurement parameters stipulated by the Technical Authority requesting the outgassing measurement. The temperature of material that is the source of the emitted material, one or m
38、ore molecular species, controls the rate at which the material is emitted. As the temperature of the material is increased the rate at which volatile materials, present in the core of the material, diffuse to the surface/vacuum interface of the material where those molecular species can be emitted i
39、nto the surrounding environment. 3.1.2.1 The source temperature is typically defined by the Technical Authority in one of two ways. Either the Technical Authority: a. Establishes a defined temperature for the screening of all nonmetallic materials by a Program/Project (simply the source or sample te
40、mperature would be fixed for all materials/measurements). Or b. Implements the practice of matching the source temperature to the application temperature at which the material (source) will be used. 3.1.2.2 A single, defined source temperature simplifies measurement control parameters but runs the r
41、isk of making a measurement unrelated to the use/application temperature for the material being tested. Tailoring the source temperature will require an understanding of the use/application temperature, possibly requiring a thermal analysis of the material with its environment, incurring additional
42、Program/Project cost. However, tailoring the measurement will avoid testing the material at a temperature that is much hotter/colder than the application temperature resulting in a rate measurement that is significantly higher/lower than would have been measured had the application temperature been
43、used for the measurement. The resulting error in any predictions based on a measurement, made at a significantly hotter/colder source temperature, could be large and result in the cost of testing additional materials or the use of a high outgassing material and degradation of a contamination sensiti
44、ve surface. 3.1.3 UVacuum Chamber PressureU The rate of sublimation of material from the surface of the source material is, in addition to the temperature of the material, dependant on the vapor pressure above the surface/environment interface. The lower the surrounding vapor pressure the less energ
45、y is required for a molecule to diffuse away from the surface of the material into the surrounding environment. 3.1.4 UMean Free Path.U If the environment that a molecule is emitted into is a vacuum, the less likely it is for the molecule to collide with another molecule, altering its direction of t
46、ravel. In an environment where viscous flow is the dominant feature, the mean free path of the molecule will Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Multiprogram/Project Common-Use Document EM50 Title: Outgassing Rate Measurements for the Scr
47、eening of Nonmetallic Materials Document No.: MSFC-HDBK-3575 Revision: Baseline Effective Date: September 16, 2009 Page 10 of 22 Pages CHECK THE MASTER LIST VERIFY THAT THIS IS THE CORRECT VERSION BEFORE USE be relatively short and the straight line migration of molecules between two surface very di
48、fficult. In a true vacuum environment ( 5 x 10P-5P torr) where molecular flow predominates, the molecular mean free path will be reasonably long and the straight line travel of molecules between surfaces will be the dominate form of mass transfer. Often this straight line path between surfaces is called the “line of sight”. 3.1.5 UThe Temperature of the Deposition SurfaceU. The surface on which the emitted, molecular species condenses is often identified as the receiver or deposition surface. For the deposition surface to be an effective collector, the temperature of the surface must be
