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TABLE 4.2 ASTM Practices Related to Corrosion of Ceramics
Standardization (ISO) and the International Electrotechnical Commission (IEC). A list of the various acronyms used for these various organizations is given in Table 4.3. The development of international standards is indispensable for the future progress of international trade.
4.2 ASTM STANDARDS
4.2.1Autoclave Expansion of Portland Cement, C-151
Samples of portland cement are exposed to water vapor at 2 MPa and 23°C for 3 hr in an autoclave. The test evaluates the potential for delayed expansion caused by the hydration of CaO or MgO or both. The percent linear expansion change is reported.
4.2.2Length Change of Hardened Hydraulic-Cement Mortars and Concrete, C-157
Samples of hardened cement or concrete are tested in limesaturated water at 23°C for 15 or 30 min depending upon sample
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TABLE 4.3 Standards Organizations and Their Acronyms
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TABLE 4.3 Continued
size. The samples are then dried at 23°C and a relative humidity of 50%. The length change is recorded after 4, 7, 14, and 28 days and 8, 16, 32, and 64 weeks.
4.2.3Resistance of Glass Containers to Chemical Attack, C-225
Attack by dilute sulfuric acid (representative of products with pH less than 5.0) or distilled water (representative of products with pH greater than 5.0) on glass bottles and the attack by pure water upon powdered glass (for containers too small to test solubility by normal methods) all at 121°C is covered in this standard test method.
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4.2.4Chemical Resistance of Mortars, Grouts, and Monolithic Surfacings, C-267
This method tests the resistance of resin, silica, silicate, sulfur, and hydraulic materials, grouts, and monolithic surfacings to a simulated service environment. Any changes in weight, appearance of the samples or test medium, and the compressive strength are recorded.
4.2.5Acid Resistance of Porcelain Enamels, C-282
This test method was developed to test the resistance of porcelain enamel coatings on stoves, refrigerators, table tops, sinks, laundry appliances, etc. to 10% citric acid at 26°C. Several drops of acid solution are placed onto a flat area about 50 mm in diameter. After 15 min, the samples are cleaned and evaluated for changes in appearance and cleanability.
4.2.6Resistance of Porcelain Enameled Utensils to Boiling Acid, C-283
Test samples 82 mm in diameter make up the bottom of glass tube that is filled with 150 mL of a solution prepared from 6 g of citric acid in 94 g of distilled water. The test cell is placed onto a hot plate and the solution is allowed to boil for 2 1/2 hr. The results are reported as the change in weight.
4.2.7Disintegration of Refractories in an Atmosphere of Carbon Monoxide, C-288
Providing a higher than expected amount of carbon monoxide normally found in service conditions, this method can be used to obtain the relative resistance of several refractory products to disintegration caused by exposure to CO. Samples are heated in nitrogen to the test temperature of 500°C then held in an
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atmosphere of 95% CO for times sufficient to produce complete disintegration of half the test samples.
4.2.8Moisture Expansion of Fired Whiteware Products, C-370
Unglazed, rod-shaped samples are tested for their resistance to dimensional changes caused by water vapor at elevated temperatures and pressures. Five samples are placed into an autoclave for 5 hr in an atmosphere of 1 MPa of steam. The amount of linear expansion caused by moisture attack is then recorded.
4.2.9Absorption of Chemical-Resistant Mortars, Grouts, and Monolithic Surfacings, C-413
Silica and silicate samples, in addition to other materials, are tested for absorption in boiling xylene after 2 hr. The percent absorption is recorded.
4.2.10Potential Expansion of PortlandCement Mortars Exposed to Sulfate, C-452
Samples of portland cement are mixed with gypsum and then immersed in water at 23°C for 24 hr and 14 days or more. The change in linear expansion is recorded.
4.2.11Disintegration of Carbon Refractories by Alkali, C-454
Carbon cubes with a hole drilled into them to form a crucible are used as the samples to test their resistance to attack from molten potassium carbonate at approximately 1000°C for 5 hr. The results of this standard practice are reported as visual observations of the degree of cracking. Variations of this procedure have been used by many to investigate the resistance of refractories to attack by molten metals and molten glasses.
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4.2.12Hydration Resistance of Basic Brick and Shapes, C-456
One-inch cubes cut from the interior of basic brick are tested in an autoclave containing sufficient water to maintain a pressure of 552 kPa at 162°C for 5 hr. This test is repeated for successive 5-hr periods to a maximum of 30 hr or until the samples disintegrate. The results are reported as visual observations of hydration and cracking.
4.2.13Hydration of Granular Dead-Burned Refractory Dolomite, C-492
A 100-g dried powder sample of dolomite that is coarser than 425 µm is tested by placing it into a steam-humidity cabinet that is maintained at 71°C and 85% humidity for 24 hr. The sample is then dried at 110°C for 30 min, and the amount of material passing a 425-µm sieve is determined.
4.2.14Hydration of Magnesite or Periclase Grain, C-544
A carefully sized material that is between 425 µm and 3.35 mm is tested by placing a dried 100-g sample into an autoclave maintained at 162°C and 552 kPa for 5 hr. The sample is then weighed after removal from the autoclave and dried at 110°C. The hydration percentage is calculated from the weight difference between the final dried weight and the weight of any material coarser than 300 µm.
4.2.15Resistance of Overglaze Decorations to Attack by Detergents, C-556; Withdrawn 1994
Overglaze decorations on pieces of dinnerware are tested by submerging the samples into a solution of sodium carbonate and water at a temperature of 95°C. Samples are removed after 2, 4, and 6 hr and rubbed with a muslin cloth. The results are
Copyright © 2004 by Marcel Dekker, Inc.