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ASTM C724-91(R2020) pdf free download

ASTM C724-91(R2020) pdf free download.Standard Test Method for Acid Resistance of Ceramic Decorations on Architectural- Type Glass
1. Scope
1.1 This test method covers qualitative determination of the acid resistance ofthe ceramic decoration on architectural glass. 1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 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 appro- priate safety, health, and environmental practices and deter- mine the applicability ofregulatory limitations prior to use. 1.4 This international standard was developed in accor- dance with internationally recognized principles on standard- ization established in the Decision on Principles for the Development of International Standards, Guides and Recom- mendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
3. Summary of Test Method
3.1 This test method qualitatively determines, by visual inspection, the degree of attack upon a ceramic decoration by a 10 % citric acid solution and a nominal 3.7 % hydrochloric acid solution.
4. Significance and Use
4.1 This test method evaluates the quality and serviceability of a ceramic decoration on architectural type glass. The degree of attack is determined using an acidic solution both quantita- tively and qualitatively. 4.2 This test method provides a convenient control test during the manufacture of the ware. 4.3 This test method is suitable for specification acceptance.
5. Reagent
5.1 Purity of Reagents—Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the Commit- tee on Analytical Reagents of the American Chemical Society, where such specifications are available. 2 Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination. 5.2 Citric Acid Solution (1 + 9)—Add ten parts by mass of reagent grade citric acid to 90 parts by mass of distilled water. Prepare fresh for each determination. 5.3 Hydrochloric Acid Solution (1 + 9)—Add ten parts by mass of reagent grade concentrated hydrochloric acid (HCl) (36 to 38 %) to 90 parts by mass of distilled water.
6. Procedure
6.1 Place four drops of each acid solution on a separate location on the surface of the ceramic decoration of the architectural glass to be tested. Cover each spot with a watchglass to retard evaporation and prevent contamination. Acid should remain on the surface of the test specimen for 15 min at 20 62 °C. 6.2 After 15 min of exposure, wash the acid solutions (1 + 9) from the test specimen with tap water and allow it to air dry.
7. Report
7.1 Report the following information: 7.1.1 The degree of attack by visual observation by grading as follows:Grade 1—No attack apparent. Grade 2—Appearance of iridescence or visible stain on the exposed surface when viewed at a 45° angle but not apparent at angles less than 30°. Grade 3—A definite stain which does not blur reflected images and is visible at angles less than 30°. Grade 4—Definite stain with a gross color change or strongly iridescent surface visible at angles less than 30° and which may blur reflected images. Grade 5—Surface dull or matte with chalking possible. Grade 6—Significant removal of enamel with pinholing evident. Grade 7—Complete removal of enamel in exposed area.
8. Precision and Bias
8.1 Precision—In round-robin testing and evaluation, the between-laboratory precision for citric-acid resistance determi- nation was found to be 61 grade (95 % student’s t). The within-laboratory precision for citric-acid resistance determi- nation is estimated at no greater than 61 grade. 8.2 Bias—No justifiable statement can be made about the bias of this test method, because the subjective nature of grading may vary considerably among operators.

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