NACE TM0108-2012 Testing of Catalyzed Titanium Anodes for Use in Soils or Natural Waters (Item No 21252).pdf

1、 Standard Test Method Testing of Catalyzed Titanium Anodes for Use in Soils or Natural Waters This NACE International standard represents a consensus of those individual members who have reviewed this document, its scope, and provisions. Its acceptance does not in any respect preclude anyone, whethe

2、r he or she has adopted the standard or not, from manufacturing, marketing, purchasing, or using products, processes, or procedures not in conformance with this standard. Nothing contained in this NACE standard is to be construed as granting any right, by implication or otherwise, to manufacture, se

3、ll, or use in connection with any method, apparatus, or product covered by letters patent, or as indemnifying or protecting anyone against liability for infringement of letters patent. This standard represents minimum requirements and should in no way be interpreted as a restriction on the use of be

4、tter procedures or materials. Neither is this standard intended to apply in all cases relating to the subject. Unpredictable circumstances may negate the usefulness of this standard in specific instances. NACE assumes no responsibility for the interpretation or use of this standard by other parties

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7、perations detailed or referred to within this standard. Users of this NACE standard are also responsible for establishing appropriate health, safety, and environmental protection practices, in consultation with appropriate regulatory authorities if necessary, to achieve compliance with any existing

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9、raw this standard no later than five years from the date of initial publication and subsequently from the date of each reaffirmation or revision. The user is cautioned to obtain the latest edition. Purchasers of NACE standards may receive current information on all standards and other NACE publicati

10、ons by contacting the NACE FirstService Department, 1440 South Creek Dr., Houston, TX 77084-4906 (telephone +1 281-228-6200). Revised 2012-06-22 Approved 2008-03-15 NACE International 1440 South Creek Drive Houston, Texas 77084-4906 +1 281-228-6200 ISBN 1-57590-216-8 2012, NACE International NACE St

11、andard TM0108-2012 Item No. 21252 NACE International i _ Foreword This NACE International standard has been prepared to provide users and manufacturers of impressed current cathodic protection (CP) anodes with a test method for evaluating the anodes ability to achieve an expected lifetime. It is app

12、licable to catalyzed titanium anodes intended for use in underground or underwater environments. This test method is intended to evaluate whether such anode complies with required specifications of design life expectancy at rated current output. This is not a quality assurance (QA) test, but rather

13、a test method that may be used to develop a QA test. The appendixes of this test method are provided for guidance and as a supplement to the test method. They outline the logic for developing a QA test based on this test method. This standard was originally prepared in 2008 by NACE Task Group (TG) 0

14、17, Anodes, Catalyzed Titanium: Testing for Use in Soils and in Waters, and it was revised by TG 017 in 2012. TG 017 is administered by Specific Technology Group (STG) 05 on Cathodic/Anodic Protection. This standard is issued by NACE under the auspices of STG 05. In NACE standards, the terms shall,

15、must, should, and may are used in accordance with the definitions of these terms in the NACE Publications Style Manual. The terms shall and must are used to state a requirement, and are considered mandatory. The term should is used to state something good and is recommended, but is not considered ma

16、ndatory. The term may is used to state something considered optional. _ TM0108-2012 ii NACE International _ NACE International Standard Test Method Testing of Catalyzed Titanium Anodes for Use in Soils or Natural Waters Contents 1. General . 1 2. Definitions 1 3. Test Apparatus 1 4. Test Electrolyte

17、 3 5. Test Procedure 4 6. Test Completion .4 7. Reporting Test Results 5 Appendix A: Discussion 5 Appendx B: Development of a Correlation Curve .6 Appendix C: Development of Acceptance Criterion 7 FIGURES: Figure 1: Test Cell with Anode Measurement Setup 2 Figure 2: Test Cells in Series .3 Figure B1

18、: Correlation Chart of Test Data 6 Figure C1: Design RequirementsCorrelation Chart of Test Data . 8 Figure C2: Sample Test Result Evaluation Using Correlation Chart . 9 _ TM0108-2012 NACE International 1 _ Section 1: General 1.1 Test Method for Catalyzed Titanium This test method is for anodes compr

19、ised of a titanium substrate to which a mixed metal oxide (MMO) catalytic coating has been applied. This test method accelerates the time-to-failure by operating the anode at higher current than the applications design requirements. 1.2 The user should not imply that this test method is mandatory fo

20、r any application of these anode materials. 1.3 Alternatively, the user may elect to use the manufacturers rating instead of developing the test methodology independently. 1.4 Limitations 1.4.1 Accelerated testing should provide conservative results by stressing the anode more severely than normal a

21、pplications. See Appendix A (Nonmandatory) for further discussion. 1.4.2 All manufacturers products may not perform identically. Comparing test samples to a correlation curve established for a different manufacturers product may lead to erroneous results. 1.4.3 The result for a sample run in the acc

22、elerated life test may be used to validate its performance at the design current density only if the correlation curve has been established for that material. See Appendix B (Nonmandatory) for development of the correlation curve using this test method. 1.4.3 This test method is not an acceptance cr

23、iterion. It may be used to develop a test criterion as shown in Appendix C (Nonmandatory). 1.4.4 This test method outlines the test conditions that must be maintained for effective comparisons. 1.4.5 Varying the test conditions may have a significant effect on the sample lifetime, leading to erroneo

24、us results. 1.4.6 The test method as described in this standard should not be interpreted as being the only correct test method that may be used. _ Section 2: Definitions Mixed Metal Oxide (MMO): A mixture of a platinum group metal (Pt, Ir, Ru) oxide and a valve metal (Ti, Ta, Nb, Zr) oxide. The mos

25、t common mixture used for cathodic protection is iridium oxide and tantalum oxide. Exact compositions may vary. _ Section 3: Test Apparatus 3.1 The test equipment is comprised of an anode (test sample), a cathode, a thermometer, a glass vessel, electrolyte agitation device (e.g., magnetic stirrer),

26、rubber stopper for tall glass beaker, a funnel for deionized water addition during the test, vent tubing, and power supply. See Figure 1. TM0108-2012 2 NACE International Figure 1: Test cell with anode measurement setup. 3.2 The glass vessel shall be sized to minimize the fluctuation in level result

27、ing from the electrolysis of water during the test and evaporative losses. A 1 L beaker may be used. 3.3 A means of securing the relative positions of the anode sample, the cathode, and the thermometer should be used. This apparatus can be a rubber stopper with holes for the various pieces of equipm

28、ent and vents or a series of stands and clamps. The gap between the anode and cathode shall be fixed. The anode top and bottom edges shall be at least 10 mm (0.4 in) from the liquid level and the bottom of the beaker, respectively. 3.4 The anode-to-cathode gap should be approximately 20 mm (0.8 in).

29、 3.5 The cathode shall be zirconium, titanium, niobium, or platinum. The size of the cathode shall be sufficient to extend from the bottom of the beaker to well above the top of the beaker. External to the cell, the cathode current conductor shall be securely connected to an insulated copper wire no

30、 smaller than 1 mm2 (#16 AWG(1). This wire shall be connected to the negative pole of the power supply. 3.6 A thermometer shall be inserted in the cell. If more than one cell is used, each cell shall have a thermometer installed. The exact type of thermometer used shall be in accordance with the gen

31、eral safety practices of the laboratory and shall not have any materials exposed to the electrolyte that could corrode and contaminate the solution. Alternately, a thermocouple may be used. (1) American Wire Gauge. Thermometer Vent Cathode Magnetic Stirrer Test Anode Weld TYPICAL TM0108-2012 NACE In

32、ternational 3 The temperature range of the thermometer shall be 20 to 100 C (68 to 212 F). Stainless steel or other metallic thermocouples shall not be exposed to the electrolyte to avoid corrosion and contamination. 3.7 The power supply shall be a constant current control, typical for laboratory us

33、e. The required amperage shall be determined from the sample size and the current density for the particular accelerated test point. For example, 5 A is appropriate for a 500 mm2 sample being run at 10 kA/m2. The required voltage depends on the number of test stations in series that may be used. Typ

34、ically, 8 volts per cell times the number of cells in series is sufficient. 3.8 Voltmeter. Most power supplies have a digital voltmeter. If using a dedicated power supply, then no additional voltmeter is necessary. If using a series of cells arrangement, then each cell shall have a digital voltmeter

35、. 3.9 The simplest operation is to use a single cell with a dedicated power supply. 3.10 Figure 2 illustrates a typical electrical series setup for duplicate evaluations. A separate coulometer or current measuring device (accurate to 1%) can be included if not incorporated within the power supply. A

36、lternatively, the product of the current times the test duration may be used. Figure 2: Test cells connected in series. 3.11 Temperature control equipment may be necessary to maintain the electrolyte within the required range depending on laboratory conditions. Essentially, a fluid may be used to in

37、put or extract heat from the electrolyte indirectly. Examples of such equipment are jacketed beakers and water bath for beakers. _ Section 4: Test Electrolyte 4.1 The composition of the electrolyte used for the test shall be suitable to force the reaction to be the electrolysis of water to produce o

38、xygen at the anode and hydrogen at the cathode. 4.1.1 The ionic concentrations shall be suitable to provide sufficient conductivity in the solution to avoid excessive voltage requirements for the power supply. 4.1.2 Some suitable electrolytes are: Cathode Test cells in series Anode Coulometer or Cur

39、rent Recorder Constant Current Power Supply TM0108-2012 4 NACE International 1 M sulfuric acid (H2SO4) 1 M sodium sulfate (Na2SO4) 180 g/L sodium sulfate with 0.1 N sulfuric acid to maintain pH at 1. 4.1.3 Suitable electrolytes should not contain chlorides. The presence of chlorides results in chlor

40、ine gas being generated in lieu of oxygen at the anode. 4.1.3.1 Chlorine gas poses handling and safety concerns during testing. 4.1.3.2 Catalyzed titanium anodes are much more severely tested for lifetime by oxygen generation than chlorine generation. 4.1.4 Fresh electrolyte shall be used for each t

41、est. 4.1.5 The concentration shall be maintained at 5% of the specified target throughout the test. 4.1.6 The temperature of the electrolyte shall be maintained at 30 5 C (86 9 F). _ Section 5: Test Procedure 5.1 The test shall be conducted in a well-ventilated laboratory fume hood. The gas released

42、 from the cell is a potentially explosive mixture of hydrogen and oxygen and must be well ventilated. 5.2 The test cell shall be filled with electrolyte and agitated with a magnetic stirrer or similar means of ensuring good mixing. 5.3 Water lost during the test shall be replaced by distilled or dei

43、onized water to maintain the electrolyte level 5%. At no time shall the level be less than that required to maintain the test equipment setup described in Section 3. 5.4 The power supply shall be energized, the current increased to the test setting, and the cell allowed to stabilize for three hours.

44、 Current flow shall be confirmed by the production of gas bubbles at both the anode and the cathode. 5.4.1 If the current changes more than 1% from the set point, then the test shall be stopped and the cause investigated. The test may be continued after appropriate corrective action. 5.4.2 If the ce

45、ll voltage exceeds the target voltage (see Section 6, Test Completion), then the test shall be paused to allow the removal of the cell from the test station. After removal of the failed cell from the circuit, the test may be started again so that the remaining samples can be tested to completion. 5.

46、4.3 Appropriate adjustments shall be made to the recorded time to ensure the time to failure is accurate for each sample. 5.4.3.1 The temperature of the electrolyte shall be controlled to 30 5 C (86 9 F). A bath or jacketed beaker may be necessary to maintain the temperature depending on ambient con

47、ditions and the operating voltage of the cell. 5.4.3.2 The cell current and voltage shall be monitored and recorded during the test hourly. 5.4.3.3 The test duration should include the three hours for assuring stabilization of cell operation before recording of voltage. _ Section 6: Test Completion 6.1 Anode failure is marked by a rapid escalation in cell voltage. The specific cell voltage is dependent on the selected current