EIA RS-186-5E-1978 STANDARD TEST METHODS FOR PASSIVE ELECTRONIC COMPONENT PARTS METHOD 5 SALT SPRAY (CORROSION).pdf

1、EIA l186-5E 78 m 3234600 0028596 I m :“ ANSVEIA RS-186-E-78 Approved October 27,1978 EIA. STANDARD I STANDARD TEST METHODS FOR PASSIVE -I ELECTRONIC COMPONENT PARTS METHOD 5: SALT SPRAY (CORROSION) I (Revision of RS-186-0, Method 5) OCTOBER 1978 Engjneeriag Depument ELBCTRONIC I.NDUSTRIES _ ASSOCiAT

2、iON EIA 186-5E 78 W 323qbOO 0028597 3 W NOTICE EIA engineering standards are designed t.o serve the public interest through eliminating mis- understandings between manufacturers and purchasers, facilitating interchangeability and improvement of products, and assisting the purchaser in selecting and

3、obtaining with mini- mum delay the proper product for his particular need. Existence of such standards shall not in any respect preclude any member or non-member of EIA from manufacturing or sell- ing products not conforming to such standards, nor shall the existence of such standards preclude their

4、 voluntary use by those other than EIA members whether the standard is to be used either domestically or internationally. Recommended standardS.are adopted by EIA without regard to whether or not their adop- tion may involve patents on articles, materials, or processes. By such action, EIA does not

5、assume any liability to any patent owner, nor does it assume any obligation whatever to parties adopting the recommended atandards. This Standard contains the major technical contents of International Electrotechnical Com- mission Publication 68-8-11, Test Ku; Salt Mist. . . It diffejrs from the Int

6、ernational mectrotechnicd Cornmission Publication 68-2-11 in pre- These differences are well known to the U.S. Cornmittee of Experts for the International Electrotechnical Commission Technical Committee 50 and resolution of these differences will be saught in future meetings of .TC-50. , . . :. scri

7、bing more accurate control of the salt solution, test conditions, and duration I. PR ICE: $3.00 l i- . I RS-186-SE Page 1 STANDARD TEST METHODS FOR PASSIVE ELECTRONIC COMPONENT PARTS METHOD 5 SALT SPRAY (CORROSION) (From EIA Standard RS-186-D and Standards Proposal No. 1271 formuluted under the cogn

8、izance of the EIA P-9 Committee on Test Methods and Procedures.) INTRODUCTION This Test Method forms a part of the EIA Standard RS-186 which contains test guidance, definitions and standard test conditions. Type I - 20% salt solution (Similar to Federal Specification QQ-“151) Type II - 5% salt solut

9、ion (Similar to ASTM B117-%T) Preferred for devices having exposed moving parts 1. PURPOSE The salt spray test is performed for the purpose of determining the adequacy of protective coatings or finishes, and has been widely used to evaluate the resistance of metals to corrosion in marine service or

10、in exposed shore.locations. This test has proved to be useful as a tool of the engineer to provide practical qualitative check on the application of metallic and other finishes to metallic surfaces. The salt spray test is an accelerated corrosion test and is a compromise since the test conditioning

11、bears relation to the natural environment only to the extent possible within the defined test procedure. This test should not be considered as a simulated test of a natural or field service condition without full consideration of its limitations. 2. APPARATUS Apparatus used in the salt-spray test sh

12、all include the following: (a) Exposure chamber with racks for supporting specimens (b) Salt-solution reservoir (c) Means for atomizing the salt solution, including suitable nozzles and compressed-air supply (d) Chamber-heating means and control (e) Means for humidifying the air at a temperature abo

13、ve the chamber temperature 2.1 Chamber - The chamber and all accessories shall be made of material which will not affect the corrosiveness of the fog, such as glass, hard rubber, plastic, or wood other than plywood. In addition, all parts which come into contact with test specimens shall be of mater

14、ials that will not cause electro- lytic corrosion. The chamber and accessories shall be so constructed and arranged that there is no direct impinging of the spray or dripping of the condensate on the specimens, so that the spray circu- lates freely about all specimens to the same degree, and so that

15、 no liquid which has come into contact with the test specimens returns to the salt-solution reservoir. The chamber shalI be properly vented. . RS-186-53 Page 2 2.2 Atomizers - The atomizer or atomizers used shall be of such design and construction as. to produce a finely divided, wet, dense fog. and

16、 dirt. The air pressure shall be suitable to produce a finely-divided, dense fag with the atomizer or atomizers used. To insure against clogging the atomizers by salt deposition in the Type 1. test, the air should have a relative humidity of at le& 85% at the point of release from the nozzle. It is

17、also necessary to humidify and warm the compressed air to meet the operating conditions specified in 5.2 for Type T and Type II tests. A satisfactory method is to pass the air in very fine bubbles through a tower containing heated water. The temperature of the water must be found hy experiment. The

18、permissible temperature increases with increasing volume of air and with decreasing heat insulation of the chamber and temperature of ita surroundings. It should not exceed a value above which an excess of moisture is introduced into the chamber or a valve which makes it impossible to meet the requi

19、rement for operating temperature. NOIE: Suggested temperatures for initial trail are as follows: 2.3 Air Supply - The compressed air entering the atomizers shall be free from all impurities such as oil Air Pressure Water Temperature ., . Type I Test (85%. RH TyGe I I Test (95% RH) . PSlG mm Mg “F. .

20、 - “C - QF “C . . . - . - 8 413.7 104 40 108.5 42.45 10 517.1 107 41.6 112 44.4 12 820.8 110 43.3 114.5 46.8 14 724.0 112.5 44.7 117 47.16 16 827.4 115 46,15 118 48.3 18 980.9 117 47.1 5 121 49.4 20 1034.3 I19 48.3 123 59,55 i, SALT SOLUTION 3.1 General - Where sodium chloride is to be employed on a

21、 dry basis, it shall contain n.Qt more than 0.1% sodium iodine and not more than 0.3% of total impurities. The solution shrrll be prepared by dissolving the specified salts in distilled water. The solution shall be kept free from solids by filtra- tion or decantation, The solution shall be maintaine

22、d at a pH of between 6.5 and 7.2. when measured at a temperature between 33.3 and 3fi.l“C (92“ and 97F). Only reagent hydrochloric acid or reagent grade sodium hydroxide shall be used to adjust the pH. The pH measurements shall be-made electromagnetically using a glass electrode with a saturated pot

23、assium-chloride bridge, or by a colorimeter method such as brom-tymol blue provided the results are equivalent to those obtained within the electrametric method, 3.2 Type I Test - The solution shall be prepared by dissolving 20 $2 parts by weight of salt (sodium chloride) in 80 parts by weight of di

24、stilled water. The solution shd be adjusted to and maintained at a specific gravity of from 1.125 to 1.157, when measured at temperatures between 33 and 36C (92 and 97F). chloride) in 95 parts of distilled water, The solution shall be adjusted to and maintained at a specific gravity of from 1.027 to

25、 1,041, when measured at temperatures between 33 and 36C (92 and 97F). 3.3 Type II Test - The solution shall be prepared by dissolving 5 21 parts by weight of salt (sodium EIA lAb-5E 78 m 323VbOO 0028bOO T m RS-186-SE Page 3 a 4. 5. 5.1 5.2 PREPARATION OF SPECIMENS Specimens shall be given a minimum

26、 of handling, particularly on the significant surfaces, and shall be prepared for test immediately before exposure. Unless otherwise specified, uncoated metallic or metallic-coated specimens shall be thoroughly ceaned of oil, dirt, and grease as necessary until the surface is free from water break.

27、The cleaning methods shall not include the use of corrosive solvents which deposit either corrosive or protective films, nor the use of abrasives other than a paste of pure magnesium oxide. Specimens having an organic coating shall not be solvent cleaned. Those portions of specimens which come into

28、contact with the support and, unless otherwise specified in the case of coated specimens or samples, cut edges and surfaces not required to be coated, shall be protected with a suitable coating of wax or similar substance impervious to moisture. PROCEDURE Location of Specimens - Unless otherwise spe

29、cified, flat specimens and, where practicable, other specimens shall be supported in such a position that the significant surface is between 15“ and 30“ from the vertical and parallel to the principal direction of horizontal flow of the fog through the chamber. Other specimens shall be positioned as

30、 specified in detail specification or by the purchaser. Whenever practicable, the specimens shall be supported from the bottom or from the side. When specimens are suspended from the top, suspension shall be by means of glass or plastic hooks or waxed string. The use of metal hooks is not permitted.

31、 Specimens shall be positioned so that they do not contact each other, so that they do not shield each other from the freely settling fog, and so that corrosion products and condensate from one specimen do not fall upon another. Operating Conditions 5.2.1 Temperature - The test shall be conducted wi

32、th a temperature in the exposure zone maintained at 35c-l.7 +LIo (950F+2z) Satisfactory methods for controlling the temperature accurately are by housing the apparatus in a properly controlled constant-temperature room, by thoroughly insulating the apparatus and preheating the air to the proper temp

33、erature prior to atomization, and by jacketing the apparatus and controlling the temperature of the water or of the air used. The use of immersion heaters for the purpose of maintaining the temperature within the chamber is prohibited. -3 )* 5.2.2 Atomization - The conditions maintained in all parts

34、 of the exposure zone shall be such that a suitable receptacle placed at any point in the exposure zone will collect from 0.5 to 3 ml. of solution per hour for each 80 sq. cm. of horizontal collecting area (10-cm. diameter) based on an average run of at least 16 hours. The solution thus collected sh

35、all have a total dissolved solids content as follows: For Type I Test - 18 to 22% sodium chloride (specific gravity from 1.126 to 1.157 when measured at a temperature between 33 to 36C (92 and 97F) For Type II Test - 4 to 6% sodium chloride (specific gravity from 1.027 to 1.041 when measured at a te

36、mperature between 33 and 36C (92 and 97F) At least two clean fog-collecting receptables shall be used, one placed near any nozzle and one placed as far as possible from all nozzles. Receptacles shall be fastened so that they are not shielded by specimens and so that no drops of solution from specime

37、ns or other sources will be collected. With nozzles made of material nonreactive to the salt solution, suitable atomization has been obtained in boxes having a volume of less than 12 cubic feet (3.4 cubic meters) with the following conditions: (a) Nozzle pressure of from 12 to 18 pounds per square i

38、nch (83 to 124 kPa) (b) Orifices of from 0.02 to 0.03 inch in diameter (5.08 to 7.62mm) EIA L8b-5E 78 I 3234b00 0028bOL L I RS-186-5E Page 4 (c) Atomization of approximately 1 gallon (3.785 liter) of solution for a 12 CU. ft. chamber When using large-size boxes having a volume considerably in excess

39、 of 12 cubic feet, the above condi- tions may have to be modified in order to meet the requirements for operating conditions. 5.3 Length of Test - Type I and II - The length. of the test period shall be stated in the component standard or specification and shall be selected from the following: in 24

40、 hours. 16,24,48,96,240,480,720 hours A tolerance of +-3% of the tota1 time shall be allowed. Unless otherwise specified in the individual standard, the test shall be run continuously for the time indicated or until definite indication of failure is observed, with no interruption except for adjustme

41、nt of the apparatus and inspection of the specimen. 6. 7. 7.1 7.2 7.3 INSPECTION AND TEST At the compbtion of the exposure period, inspection and test shall be m.ade as specified in the individual standard. To aid in examination, salt deposits shall Ere removed by a gentle wash or dip in running water not warmer than 37.8“C (100F) in a light brushing. SUMMARY The following details shall be specified in the indivdual standard: Type of test. Test - length in hours (53). Inspection and Test after exposure (6).