1Scope This test method is designed to determine the corrosive properties of flux residues under extreme environ-mental conditions.A pellet of solder is melted in contact with the test flux on a sheet metal test piece.The solder is then exposed to prescribed conditions of humidity and the result-ing corrosion,if any,is assessed visually.
2Applicable Documents
IPC J-STD-004Requirements for Soldering Fluxes
IPC-TM-650Test Methods Manual
2.3.34Solids Content,Flux for Fluxes for Soft Soldering IEC61189-5Test Methods for Electrical Materials,Intercon-
nection Structures and Assemblies-Part5:Test Methods for Printed Board Assemblies
3Test Specimen At least0.035g of flux solids,0.3g sol-der paste,1g wire,or1g preform with an equivalent amount of solids.Flux solids are defined as the residue described in IPC-TM-650,Test Method2.3.34,Solids Content,Fluxes.All solvent must have been evaporated from the specimen in a chemical fume hood.
4Apparatus and Reagents
4.1Apparatus
4.1.1Solder pot.
4.1.2Humidity chamber capable of achieving40±3°C [104±
5.4°F]and93±5%relative humidity.百美图之
4.1.3Air circulating drying oven.
4.1.4Microscope having20X minimum.
4.1.5Analytical balance capable of weighing0.001g.
4.1.6Three50mm x50mm x0.5mm[1.969in x1.969in x0.00197in]99%pure copper sheets.
4.1.719mm[0.748in]steel ball(approximate).
4.1.8Laboratory press.4.1.9Tongs.
4.2Reagents All chemicals must be reagent grade and water must be deionized(2megohm-cm minimum resistivity recommended).
4,2,1Ammonium persulphate.
4.2.2Sulfuric acid,relative density1.84.
4.2.3Degreasing agent:acetone,or petroleum ether.
5Procedures
5.1Chemicals
5.1.1Ammonium persulphate(25%m/v in0.5%v/v sulfuric acid).Dissolve250g of ammonium persulphate in water and add cautiously5ml of5%sulfuric acid(relative density1.84). Mix,cool,dilute to1liter and mix.This solution should be freshly prepared.
5.1.2Sulfuric acid(5%v/v).To400ml of water cautiously add50ml of sulfuric acid(relative density1.84).Mix,cool, dilute to1liter and mix.
5.2Test Panel
5.2.1Form a3.0mm[0.018in](approximate)deep circular depression in the center of the copper test panel by forcing a 19.0mm[0.018in]steel ball into a25(approximate)mm hole to form a cup.
5.2.2Bend one corner of the test panel up to facilitate sub-sequent handling with tongs.
运筹与
管理5.3Test Panel Pretreatment
5.3.1Immediately before performing test,pretreat as follows using clean tongs for handling.
5.3.2Degrease with a suitable neutral organic solvent such as acetone,or petroleum ether.
Material in this Test Methods Manual was voluntarily established by Technical Committees of IPC.This material is advisory only
and its use or adaptation is entirely voluntary.IPC disclaims all liability of any kind as to the use,application,or adaptation of this
material.Users are also wholly responsible for protecting themselves against all claims or liabilities for patent infringement.
Equipment referenced is for the convenience of the user and does not imply endorsement by IPC.
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5.3.3Immerse in5%sulfuric acid(by volume)at65±5°C [149±9°F]for one minute to remove the tarnish film.
5.3.4Immerse in a solution of25%m/v ammonium persul-phate(in0.5%v/v sulfuric acid)at23±2°C[73.4±3.6°F] for one minute to etch the surface uniformly.
5.3.5Wash in running tap water for five seconds.Immerse in5%sulfuric acid(by volume)at23±2°C[73.4±3.6°F]for one minute.
5.3.6Wash for five seconds in running tap water,then rinse thoroughly in deionized water.
5.3.7Rinse with acetone.
5.3.8Allow to dry in clean air.毛细管数
Note:Use the test piece as soon as possible or store up to one hour in a closed container.
5.4Solder for Liquid or Paste Flux Test
5.4.1Weigh a1.00±0.05gram specimen of solid solder.
5.4.2Degrease the solder specimen with a suitable neutral organic solvent such as acetone,or petroleum ether.
5.4.3Solder may be in the form of pellets or tight spirals of solid solder wire.
5.5Test
5.5.1Heat solder pot so that solder bath stabilizes at235±5°C[455±9°F].
5.5.2Liquid or Paste Flux
5.5.2.1Place0.035g of flux solids into the depression in the test panel.Add the solid solder pellets or spirals.
5.5.2.2Using tongs,lower the test panel onto the surface of the molten solder.
5.5.2.3Allow the test panel to remain in contact with the bath until the solder specimen in the depression of the test panel melts.Maintain this position for5±1seconds before removing the test panel from the bath.Cool the test panel to room temperature.5.5.3Cored Wire or Cored Preform
5.5.3.1Place1gram of flux cored wire or perform into the depression in the test panel.
5.5.3.2Using tongs,lower the test panel onto the surface of the molten solder.
5.5.3.3Allow the test panel to remain in contact with the bath until the solder specimen in the depression of the test panel melts.Maintain this position for5±1seconds before removing the test panel from the bath.Cool the test panel to room temperature.
5.5.4Solder Paste
5.5.4.1Place0.3g of solder paste into the depression in the test panel.
海森堡
5.5.4.2Allow the test panels to remain in contact with the bath until the solder specimen in the depression of the test panel melts.Maintain this position for60±5seconds before removing the test panel from the bath.Cool the test panel to room temperature.
5.5.4.3Alternately,process the panels through a reflow sol-dering process using the temperature profile recommended by the vendor.
5.6Humidity Exposure
5.6.1Carefully examine the test specimen at20X magnifica-tion for subsequent comparison after humidity exposure. Record observations,especially any discoloration(see8.2).
5.6.2Preheat test panel to40±1°C[104±1.8°F]for30±2minutes.
5.6.3Humidity Soak
5.6.3.1Place the test specimen vertically in a preset humid-ity chamber at40±1°C[104±1.8°F]and93±2%relative humidity.
5.6.3.2Alternately,the specimen may be placed in a tem-perature humidity chamber and heated to40°C[1.8°F]and
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held for30minutes.The humidity should then be increased to 93%RH.3721
上网助手 低碳世界5.6.3.3Expose specimen to the above environment for240 hours(10days).M and H fluxes may be tested in the cleaned, as well as uncleaned,condition.Specimens shall be cleaned per the manufacturers instructions.
5.7Evaluation
5.7.1After the exposure period,remove test specimens from humidity chamber,examine at20X magnification and compare with observations noted in
6.5(see8.2).
5.7.2For purposes of this test method,the following defini-tion of corrosion shall prevail:‘‘A chemical r
eaction between the copper,the solder,and the constituents of the flux resi-dues,which occurs after soldering and during exposure to the above environmental conditions.‘‘Corrosion for this test is classified as follows:
5.7.2.1Minor Corrosion Any initial change of color,which may develop when the test panel is heated during soldering,is disregarded.Discrete white or colored spots in the flux resi-dues or a color change to green-blue without pitting of the copper or formation of excrescences is regarded as minor corrosion.
5.7.2.2Major Corrosion Any initial change of color which may develop when the test panel is heated during soldering is disregarded.Subsequent development of green-blue discol-oration with observation of pitting of the copper panel or excrescences at the interfaces of the flux residue and copper boundary,is regarded as major corrosion.
6Notes
6.1Questionable results may be confirmed by analyzing the suspected corrosion via Energy Dispersive X-ray Spectros-copy(EDS)for the presence of copper.
6.2Color photos before and after the test are valuable tools in identifying and documenting corrosion.
6.3Safety Observe all appropriate precautions on MSDS for chemicals involved in this test method.
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