ASTM B827-2005(2014) Standard Practice for Conducting Mixed Flowing Gas &40 MFG&41 Environmental Tests《传导混流气 (MFG) 的环境试验的标准实施规程》.pdf
《ASTM B827-2005(2014) Standard Practice for Conducting Mixed Flowing Gas &40 MFG&41 Environmental Tests《传导混流气 (MFG) 的环境试验的标准实施规程》.pdf》由会员分享,可在线阅读,更多相关《ASTM B827-2005(2014) Standard Practice for Conducting Mixed Flowing Gas &40 MFG&41 Environmental Tests《传导混流气 (MFG) 的环境试验的标准实施规程》.pdf(9页珍藏版)》请在麦多课文档分享上搜索。
1、Designation: B827 05 (Reapproved 2014)Standard Practice forConducting Mixed Flowing Gas (MFG) Environmental Tests1This standard is issued under the fixed designation B827; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of
2、 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 practice provides procedures for conducting envi-ronmental tests involving exposures to controlled quantities of
3、corrosive gas mixtures.1.2 This practice provides for the required equipment andmethods for gas, temperature, and humidity control whichenable tests to be conducted in a reproducible manner. Repro-ducibility is measured through the use of control couponswhose corrosion films are evaluated by mass ga
4、in, coulometry,or by various electron and X-ray beam analysis techniques.Reproducibility can also be measured by in situ corrosion ratemonitors using electrical resistance or mass/frequency changemethods.1.3 The values stated in SI units are to be regarded asstandard. No other units of measurement a
5、re included in thisstandard.1.4 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 become familiarwith all hazards including those identified in the appropriateMaterial Safety Data Sheet (MSDS)
6、 for this product/materialas provided by the manufacturer, to establish appropriatesafety and health practices, and determine the applicability ofregulatory limitations prior to use. See 5.1.2.4.2. Referenced Documents2.1 ASTM Standards:2B542 Terminology Relating to Electrical Contacts and TheirUseB
7、765 Guide for Selection of Porosity and Gross Defect Testsfor Electrodeposits and Related Metallic CoatingsB808 Test Method for Monitoring ofAtmospheric CorrosionChambers by Quartz Crystal MicrobalancesB810 Test Method for Calibration ofAtmospheric CorrosionTest Chambers by Change in Mass of Copper
8、CouponsB825 Test Method for Coulometric Reduction of SurfaceFilms on Metallic Test SamplesB826 Test Method for Monitoring Atmospheric CorrosionTests by Electrical Resistance ProbesB845 Guide for Mixed Flowing Gas (MFG) Tests for Elec-trical ContactsD1193 Specification for Reagent WaterD2912 Test Met
9、hod for Oxidant Content of the Atmosphere(Neutral Ki) (Withdrawn 1990)3D2914 Test Methods for Sulfur Dioxide Content of theAtmosphere (West-Gaeke Method)D3449 Test Method for Sulfur Dioxide in Workplace Atmo-spheres (Barium Perchlorate Method) (Withdrawn 1989)3D3464 Test Method for Average Velocity
10、in a Duct Using aThermal AnemometerD3609 Practice for Calibration Techniques Using Perme-ation TubesD3824 Test Methods for Continuous Measurement of Ox-ides of Nitrogen in theAmbient or WorkplaceAtmosphereby the Chemiluminescent MethodD4230 Test Method of Measuring Humidity with Cooled-Surface Conde
11、nsation (Dew-Point) HygrometerE902 Practice for Checking the Operating Characteristics ofX-Ray Photoelectron Spectrometers (Withdrawn 2011)3G91 Practice for Monitoring Atmospheric SO2DepositionRate for Atmospheric Corrosivity Evaluation3. Terminology3.1 Definitions relating to electrical contacts ar
12、e in accor-dance with Terminology B542.4. Significance and Use4.1 Mixed flowing gas (MFG) tests are used to simulate oramplify exposure to environmental conditions which electricalcontacts or connectors can be expected to experience in variousapplication environments (1, 2).41This practice is under
13、the jurisdiction ofASTM Committee B02 on NonferrousMetals and Alloys and is the direct responsibility of Subcommittee B02.11 onElectrical Contact Test Methods.Current edition approved Oct. 1, 2014. Published October 2014. Originallyapproved in 1992. Last previous edition approved in 2009 as B827 05
14、(2009)2.DOI: 10.1520/B0827-05R14.2For 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.3The last approved version o
15、f this historical standard is referenced onwww.astm.org.4The boldface numbers in parentheses refer to the list of references at the end ofthis standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14.2 Test samples which have been e
16、xposed to MFG testshave ranged from bare metal surfaces, to electrical connectors,and to complete assemblies.4.3 The specific test conditions are usually chosen so as tosimulate, in the test laboratory, the effects of certain represen-tative field environments or environmental severity levels onstan
17、dard metallic surfaces, such as copper and silver couponsor porous gold platings (1, 2).4.4 Because MFG tests are simulations, both the test con-ditions and the degradation reactions (chemical reaction rate,composition of reaction products, etc.) may not always re-semble those found in the service e
18、nvironment of the productbeing tested in the MFG test. A guide to the selection ofsimulation conditions suitable for a variety of environments isfound in Guide B845.4.5 The MFG exposures are generally used in conjunctionwith procedures which evaluate contact or connector electricalperformance such a
19、s measurement of electrical contact resis-tance before and after MFG exposure.4.6 The MFG tests are useful for connector systems whosecontact surfaces are plated or clad with gold or other preciousmetal finishes. For such surfaces, environmentally producedfailures are often due to high resistance or
20、 intermittencescaused by the formation of insulating contamination in thecontact region. This contamination, in the form of films andhard particles, is generally the result of pore corrosion andcorrosion product migration or tarnish creepage from pores inthe precious metal coating and from unplated
21、base metalboundaries, if present.4.7 The MFG exposures can be used to evaluate novelelectrical contact metallization for susceptibility to degradationdue to environmental exposure to the test corrosive gases.4.8 The MFG exposures can be used to evaluate theshielding capability of connector housings
22、which may act as abarrier to the ingress of corrosive gases.4.9 The MFG exposures can be used to evaluate thesusceptibility of other connector materials such as plastichousings to degradation from the test corrosive gases.4.10 The MFG tests are not normally used as porosity tests.For a guide to poro
23、sity testing, see Guide B765.4.11 The MFG tests are generally not applicable where thefailure mechanism is other than pollutant gas corrosion such asin tin-coated separable contacts.5. Apparatus5.1 Apparatus required to conduct MFG tests are dividedinto four major categories, corrosion test chamber,
24、 gas supplysystem, chamber monitoring system, and chamber operatingsystem.5.1.1 Corrosion Test Chamber:5.1.1.1 The chamber shall consist of an enclosure made ofnonreactive, low-absorbing, nonmetallic materials containedwithin a cabinet or oven capable of maintaining the tempera-ture to a maximum tol
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