ASTM B827-05(2014)
传导混流气 (MFG) 的环境试验的标准实施规程

Standard Practice for Conducting Mixed Flowing Gas &40;MFG&41; Environmental Tests

被代替

标准号

ASTM B827-05(2014)

发布

2005年

发布单位

美国材料与试验协会

替代标准

ASTM B827-05(2020)

当前最新

ASTM B827-05(2020)

 

 

引用标准

ASTM B542 ASTM B765 ASTM B808 ASTM B810 ASTM B825 ASTM B826 ASTM B845 ASTM D1193 ASTM D2914 ASTM D3449 ASTM D3464 ASTM D3609 ASTM D3824 ASTM D4230 ASTM E902 ASTM G91

适用范围

4.1 Mixed flowing gas (MFG) tests are used to simulate or amplify exposure to environmental conditions which electrical contacts or connectors can be expected to experience in various application environments (1, 2).4

4.2 Test samples which have been exposed to MFG tests have ranged from bare metal surfaces, to electrical connectors, and to complete assemblies.

4.3 The specific test conditions are usually chosen so as to simulate, in the test laboratory, the effects of certain representative field environments or environmental severity levels on standard metallic surfaces, such as copper and silver coupons or porous gold platings (1, 2).

4.4 Because MFG tests are simulations, both the test conditions and the degradation reactions (chemical reaction rate, composition of reaction products, etc.) may not always resemble those found in the service environment of the product being tested in the MFG test. A guide to the selection of simulation conditions suitable for a variety of environments is found in Guide B845.

4.5 The MFG exposures are generally used in conjunction with procedures which evaluate contact or connector electrical performance such as measurement of electrical contact resistance before and after MFG exposure.

4.6 The MFG tests are useful for connector systems whose contact surfaces are plated or clad with gold or other precious metal finishes. For such surfaces, environmentally produced failures are often due to high resistance or intermittences caused by the formation of insulating contamination in the contact region. This contamination, in the form of films and hard particles, is generally the result of pore corrosion and corrosion product migration or tarnish creepage from pores in the precious metal coating and from unplated base metal boundaries, if present.

4.7 The MFG exposures can be used to evaluate novel electrical contact metallization for susceptibility to degradation due to environmental exposure to the test corrosive gases.

4.8 The MFG exposures can be used to evaluate the shielding capability of connector housings which may act as a barrier to the ingress of corrosive gases.

4.9 The MFG exposures can be used to evaluate the susceptibility of other connector materials such as plastic housings to degradation from the test corrosive gases.

4.10 The MFG tests are not normally used as porosity tests. For a guide to porosity testing, see Guide B765.

4.11 The MFG tests are generally not applicable......

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