ASTM C949 Test for Porosity in Vitreous Whitewares by Dye Penetration

Scope:

ASTM C949 is used for determining whether a ceramic has been properly fired (matured). Some degree of penetration is acceptable for the use or commercial quality of the item being tested. However, penetration of any extent may negate the usefulness of the ceramic. 

Test Procedure:

In ASTM C949, unglazed fragments of vitreous whiteware products are randomly selected. They are immersed in a fuchsin dye solution at one or more pressures for a specific time. They are dried, broken, and inspected for the extent of dye penetration in the fragments. 

Video 01: Dye penetration inspection

Specimen size:

Freshly broken fragments, approximately 1⁄4 inches, are the smallest dimension, and up to 3⁄4 inches, are the largest dimension of the whiteware ceramic. At least 75 % of the surface should be free of glaze or other surface treatment. 

Data:

The penetration of the dye indicates the porosity of the specimens.  

Conclusion:

ASTM C949 is used for determining whether a ceramic has been properly fired (matured).