ASTM G97-97

Standard Test Method for Laboratory Evaluation of Magnesium Sacrificial Anode Test Specimens for Underground Applications

SCOPE
1.1 This test method describes a laboratory procedure that measures the two fundamental performance properties of magnesium sacrificial anode test specimens operating in a saturated calcium sulfate, saturated magnesium hydroxide environment. The two fundamental properties are electrode (oxidation potential) and ampere hours (Ah) obtained per unit mass of specimen consumed. Magnesium anodes installed underground are usually surrounded by a backfill material that typically consists of 75% gypsum (CaSO42H2 O), 20% bentonite clay, and 5% sodium sulfate (Na2SO4 ). The calcium sulfate, magnesium hydroxide test electrolyte simulates the long term environment around an anode installed in the gypsum-bentonite-sodium sulfate backfill.
1.2 This test method is intended to be used for quality assurance by anode manufacturers or anode users. However, long term field performance properties may not be identical to property measurements obtained using this laboratory test.
Note 1--Refer to Terminology G15 for terms used in this test method.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific precautions, See Section 7 and Paragraph 8.1.1.

General Information

• Status: Historical
• Publication Date: 09-Oct-1997
• Technical Committee: G01 - Corrosion of Metals
• Drafting Committee: G01.10 - Corrosion in Soils

Relations

• Replaced By: ASTM G97-97(2002)e1 - Standard Test Method for Laboratory Evaluation of Magnesium Sacrificial Anode Test Specimens for Underground Applications
• Effective Date: 10-Oct-1997

Standards Content (Sample)

Designation: G 97 – 97
AMERICAN SOCIETY FOR TESTING AND MATERIALS
100 Barr Harbor Dr., West Conshohocken, PA 19428
Reprinted from the Annual Book of ASTM Standards. Copyright ASTM
Standard Test Method for
Laboratory Evaluation of Magnesium Sacrificial Anode Test
1
Specimens for Underground Applications
This standard is issued under the fixed designation G 97; the number immediately following the designation indicates the year of original
adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript
epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope ANSI/NFPA 480 Storage, Handling, and Processing of
4
Magnesium, 1987 Edition
1.1 This test method describes a laboratory procedure that
measures the two fundamental performance properties of
3. Summary of Test Method
magnesium sacrificial anode test specimens operating in a
3.1 A known direct current is passed through test cells
saturated calcium sulfate, saturated magnesium hydroxide
connected in series. Each test cell consists of a pre-weighed
environment. The two fundamental properties are electrode
test magnesium alloy anode specimen, a steel pot container
(oxidation potential) and ampere hours (Ah) obtained per unit
cathode, and a known electrolyte. Test specimen oxidation
mass of specimen consumed. Magnesium anodes installed
potential is measured several times during the 14-day test and
underground are usually surrounded by a backfill material that
1 h after the current is turned off at the end of the test. The total
typically consists of 75 % gypsum (CaSO ·2H O), 20 % ben-
4 2
Ah passed through the cells are measured. At the conclusion of
tonite clay, and 5 % sodium sulfate (Na SO ). The calcium
2 4
the test, each test specimen is cleaned and weighed. The Ah
sulfate, magnesium hydroxide test electrolyte simulates the
obtained per unit mass of specimen lost is calculated.
long term environment around an anode installed in the
gypsum-bentonite-sodium sulfate backfill.
4. Significance and Use
1.2 This test method is intended to be used for quality
4.1 This test is a guide for evaluating magnesium anodes.
assurance by anode manufacturers or anode users. However,
The degree of correlation between this test and service perfor-
long term field performance properties may not be identical to
mance has not been fully determined.
property measurements obtained using this laboratory test.
5. Apparatus
NOTE 1—Refer to Terminology G 15 for terms used in this test method.
5.1 The basic test equipment consists of the following:
1.3 This standard does not purport to address all of the
5.1.1 Direct Current Power Source,(optional), capable of
safety concerns, if any, associated with its use. It is the
delivering at least 2 mA and 12 V.
responsibility of the user of this standard to establish appro-
5.1.2 Steel Cathode Test Pot, as shown in Fig. 1.
priate safety and health practices and determine the applica-
5.1.3 Copper Coulometer, as shown in Fig. 2, or Electronic
bility of regulatory limitations prior to use. For specific
Coulometer.
precautions, See Section 7 and Paragraph 8.1.1.
5.1.4 Saturated Calomel Reference Electrode.
7
2. Referenced Documents
5.1.5 Electrometer, with an input impedance of 10 or
greater ohms.
2.1 ASTM Standards:
2
5.1.6 Balance, 100-g capacity with 0.1 mg sensitivity.
D 1193 Specification for Reagent Water
5.1.7 Drying Oven, with temperature capability of 110°C or
G 3 Practice for Conventions Applicable to Electrochemical
3
higher.
Measurements in Corrosion Testing
G 15 Terminology Relating to Corrosion and Corrosion
6. Reagents
3
Testing
6.1 Test Electrolyte, Saturated Calcium Sulfate-Magnesium
G 16 Guide for Applying Statistics to Analysis of Corrosion
3
Hydroxide Solution—Add 5.0 g of reagent grade CaSO ·2H O,
Data
4 2
0.1 g of reagent grade Mg(OH) , to 1000 mL of Type IV or
2.2 American National Standard:
2
better reagent grade water (see Specification D 1193).
6.2 Coulometer Solution—Add 235 g of reagent grade
3
1
This test method is under the jurisdiction of ASTM Committee G-1 on CuSO ·5H O, 27 mL 98 % H SO ,50cm undenatured ethyl
4 2 2 4
Corrosion of Metals, and is the direct responsibility of Subcommittee G01.10 on
alcohol to 900 mL of Type IV or better reagent grade water.
Soils.
Current edition approved Oct. 10, 1997. Published December 1997. Originally
e1
published as G 97 – 89. Last previous edition G 97 – 89 (1995) .
2 4
Annual Book of ASTM Standards, Vol 11.01. Available from National Fire Protection Association, Inc., Batterymarch Park,
3
Annual Book of ASTM Standards, Vol 03.02. Quincy, MA 02269.
1

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G97
8.1.2.4 Clearance angle—Band saw 5 20 to 30°, power
hacksaw 5 20 to 30°.
8.2 Rinse each machined test specimen with water, rinse
FIG. 1 Detail of Test Pot
with acetone, dry in an oven at 105°C for 30 min, cool, and
weigh to the nearest 0.1 mg.
NOTE 2—Caution: The specim
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