1、Designation: B995 15aStandard Test Method forChloride Resistance Test for Chromium Electroplated Parts(Russian Mud Test)1This standard is issued under the fixed designation B995; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the
2、year of 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 standard details a laboratory method to acceleratethe effects of exposure to hygroscopic corrosive chlori
3、decompounds on electroplated chromium components. It isapplicable to any substrate and coating system that utilizeselectroplated chromium as the final metallic coating.1.2 Field experience has shown that hygroscopic chloridesare significantly more aggressive than sodium chloride towardchromium elect
4、roplated deposits. The most common of whichis calcium chloride.1.3 The standard does not specify exposure periods to beused for a specific product nor the interpretation to be given tothe results. The suitability of this test and correlation of resultswith service experience should be determined bef
5、ore it isspecified for coating systems.1.4 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the
6、user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:B117 Practice for Operating Salt Spray (Fog) ApparatusB368 Test Method for Copper-Accelerated Acetic Acid-Salt
7、Spray (Fog) Testing (CASS Test)D1193 Specification for Reagent Water3. Significance and Use3.1 This test replicates in the laboratory the corrosiveactions of a film containing hygroscopic chlorides and solidmaterial (mud) on electroplated chromium. The tests reactivemedia, the test slurry, was devel
8、oped to simulate the film foundon electroplated chromium deposits during a winter in Russia,thus the common name for the test, Russian Mud Test.3.2 This test is used for specification acceptance, simulatedservice evaluation, manufacturing control, and research anddevelopment. It was developed specif
9、ically for use on compo-nents with electrodeposited chromium coatings exposed tohygroscopic chlorides. Test and production specimens may beused. Use of a standardized test could help in developingimproved quality of chromium electrodeposited componentsand lead to the development of improved electrop
10、lated chro-mium systems.3.3 This test simulates the amount of electrodepositeddecorative and functional chromium deposit lost when exposedto the combination of “mud/solid material” and hygroscopicchlorides, most commonly calcium chloride. The metric is theloss of only the chromium and adjacent nicke
11、l layer. Other testsused with nickel/chromium electroplated components, such asCASS (Test Method B368), simulate the resistance of the partto basis metal corrosion involving all of the componentsdeposits and substrate.4. Apparatus4.1 The apparatus required for this test consists of anenvironment cha
12、mber capable of controlling both temperatureand humidity within the specified range (see 7.4). The chambermust be large enough to hold the test specimens withouttouching one another or the walls of the chamber. Also, thereaction products formed on one specimen shall not fall onanother specimen. Mate
13、rials of construction shall not affect thecorrosiveness of the test environment, nor be themselvescorroded by the test environment. Practice B117 offers a guidefor chamber design.1This test method is under the jurisdiction ofASTM Committee B08 on Metallicand Inorganic Coatings and is the direct resp
14、onsibility of Subcommittee B08.10 onTest Methods.Current edition approved Nov. 1, 2015. Published December 2015. Originallyapproved in May 2015. Last previous edition approved in 2015 as B995-15. DOI:10.1520/B99515A.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken,
15、 PA 19428-2959. United States15. Reagents and Materials5.1 Table 1 specifies the laboratory grade consumable ma-terials used in this test.TABLE 1 ACS Reagent-Grade or Equivalent ConsumableMaterialsItem Name CAS # Description/UseWater (Practice D1193 Type IV) 7732-18-5 Test slurry ElectrolyteKaolin 1
16、332-58-7 Soil/mud base mediaCalcium Chloride Dihydrate 10035-04-8 Corrosive mediaSodium HydroxideA1310-73-2 Solution pH adjustmentSulfuric AcidA7664-93-9 Solution pH adjustmentIsopropyl Alcohol 67-63-0 Test sample cleaningAFor ease of control, solutions that are approximately 0.25 N are recommended.
17、6. Test Slurry Formulation6.1 Stock SolutionUsing the consumable materials listedin Table 1, prepare a stock solution containing dissolvedcalcium chloride produced by maintaining a ratio of 57.5 gcalcium chloride dihydrate for every 94 mL of water and 8 mLof 0.25 N NaOH. The pH of the solution shall
18、 be 9.5 6 0.5. Ifnot, investigate the possibility of contaminated or low purityconsumables.6.1.1 1 A different normality of NaOH may be used,however, the total volume of liquid (originally 8 mL of 0.25 NNaOH solution and 94 mL of water) shall be maintained at102 mL. Adjust the volume of added water
19、to compensate forthe difference in the volume of NaOH solution needed. Thetrial stock solution produced in 6.1 is used to start formulatingthe composition of the final stock solution.Astock solution pHof 9.5 6 0.5 is only required when the equivalent of 0.25 NNaOH is used in 6.1. The procedure in 6.
20、2 might establish therequirement of a different concentration of NaOH for the finalstock solution and thus a different pH.6.2 Test SlurryMix the stock solution with kaolin at a ratioof 3 g kaolin per 5 mL stock solution (6.1).6.2.1 Measure the pH of the test slurry by diluting a portionof the test s
21、lurry (for example, 10 mL) with an equal volume ofTable 1 water. The pH of the diluted test slurry shall be 7.0 60.5.NOTE 1The pH of the diluted test slurry is measured by using acalibrated digital pH meter. A self-flushing probe is recommended due tothe high concentration of solids in the sample.NO
22、TE 2Diluted test slurry cannot be used on test samples.6.2.2 If the pH of the diluted test slurry is not 7.0 6 0.5, itshall be titrated with standardized solutions of either NaOH orsulfuric acid until the required pH is obtained. Use the titrationvalue to calculate the final amount of NaOH required
23、andprepare another batch of stock solution (6.1) and test slurry(6.2) using the same batches of consumable materials. Repeat6.1 and 6.2 until the diluted test slurry pH is 7.0 6 0.5 withoutfurther adjustment.6.2.3 The formulation developed to obtain the required pHof 7.0 6 0.5 shall be used as long
24、as the same batches ofconsumable materials are used.NOTE 3 Field experience has established that Kaolin can differ bybatch and supplier. This is the main reason that it is necessary to firstestablish the required volume of NaOH needed to make the stock solution(6.1) used, in turn, to prepare the tes
25、t slurry (6.2) with the set ofconsumable materials being used. Before establishing the required volumeof NaOH, it is recommended that all consumable materials listed in Table1 be available for the production of many batches of test slurry.NOTE 4The pH of the test slurry is a critical requirement for
26、 theRussian Mud Test, not the pH of the stock solution.6.3 The shelf life of the stock solution (6.1) is 1 month. Theshelf life of the test slurry (6.2)is12h.NOTE 5For convenience, make up enough stock solution to last 1month and then use it to prepare the test slurry just prior to conducting theRus
27、sian Mud test.7. Procedure7.1 Clean the test specimen using a clean, non-abrasivecloth soaked with a 50/50 volume mixture of isopropyl alcoholand Type IV water. Ensure that the test piece is fully driedbefore proceeding.7.2 Identify the surfaces on the specimens being tested thatare to be evaluated
28、during the test.At each designated location,apply approximately 0.6 mL of the slurry in a circular spotusing a pipette, eye dropper or similar application method. Thesolution shall be applied at the center of the circle and allowedto spread out naturally. Do not manually spread the slurry afterapply
29、ing it to the surface. Each application spot should beseparated from other spots by at least 1 cm in all directions. Ifenough room is available at any location, apply up to threeduplicate spots to observe possible variability in test results.7.3 Test pieces shall be placed into the test chamber so t
30、hatthe test slurry is as horizontal as possible, so that the slurrydoes not run off of the test specimen onto another test specimenand each test piece is completely exposed to the testenvironment, and the samples do not interfere with each other.7.4 The test chamber shall be controlled at a temperat
31、ure of60 6 3C and 23 6 5% relative humidity.8. Evaluation of Results8.1 The test duration, minimum number of test spots,inspection frequency, and test results (Appendix X1) must bespecified and agreed upon by the requestor and laboratory priorto the beginning of the test.8.2 At each inspection inter
32、val, remove test specimensfrom, or turn off, the test chamber. Remove the agreed upontest spots from each sample by wiping the areas with warm tapwater and a clean, non-abrasive cloth. Evaluate each area fromwhich the slurry was removed under 10 magnification.Assigna rating to each spot according to
33、 the scale in Appendix X1.The acceptance criteria for evaluation shall be specified by therequestor. Continue the test in the controlled chamber until thenext inspection interval or until the end of the test.8.3 The total amount of time per day the environmentalchamber is open for the inspections sh
34、all not exceed 60minutes. There shall be only one inspection per day. Ifoperational conditions dictate that these requirements cannotbe met, it shall be noted in the laboratory report.NOTE 6Maintain a record of the test spots after each inspection bymarking the test specimens, photographs, or other
35、suitable method.9. Records and Report9.1 The following information shall be included in the testreport unless previously agreed upon between the requestorand the laboratory:B995 15a29.1.1 Identification of the test specimens and source, includ-ing plating cycle and source.9.1.1.1 Plating cycle, incl
36、uding thickness and type of chro-mium layer.9.1.1.2 Identification of the layer prior to the chromiumdeposit and, if applicable, after the chromium layer.9.1.2 The chamber temperature and relative humidity.9.1.3 The frequency of evaluation, including the time inter-vals.9.1.4 Photographs of test spo
37、ts after each evaluation.9.1.5 The test results using Appendix X1.10. Precision and Bias10.1 Information is being generated to develop the precisionand bias of this test method.10.2 The reliability, reproducibility, and accuracy of the testdepend on proper and consistent control of a number of facto
38、rs,including:10.2.1 Preparation of the test solutions,10.2.2 Cleaning of the test samples,10.2.3 Chamber temperature and relative humidity,10.2.4 Positioning of the specimens in the test chamber, and10.2.5 Frequency of evaluation including the time interval.11. Keywords11.1 chloride; chromium; corro
39、sion; decorative; electroplat-ing; finishes; functional; Russian MudAPPENDIX(Nonmandatory Information)X1. CHROMIUM LOSS RATING SCALEB995 15a3FIG. X1.1 Chromium Loss Rating Scale at 10 MagnificationB995 15a4ASTM International takes no position respecting the validity of any patent rights asserted in
40、connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the res
41、ponsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive caref
42、ul consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International
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