Scope:

The ASTM C777 test method is used to measure the sulfide resistance of ceramic decorations on glass in order to ensure their vital durability. This test qualitatively determines the degree of attack upon a ceramic decoration, by a nominal 4% acetic acid solution containing 1 mL of saturated sodium sulfide solution per 100 ml of the acetic acid solution, through a visual assessment. ASTM C777 gives an indication of performance when the decorations are subjected to sulfide attacks.

Test Procedure:

In ASTM C777, the specimen is immersed in a 4 % acetic acid solution containing 1 mL of saturated sodium sulfide solution per 100 mL of acetic acid solution in a suitably closed container at room temperature. A duplicate piece of ware (not exposed to the solution) is kept with the decoration under study as an extra aid in measuring the degree of chemical activity on the specimen under test. After 15 minutes, the specimen is taken out from the solution and left to dry in the air. After 15 minutes, an eye examination determines the severity of the attack.

Specimen Size : 

A glass (of known resistance) with ceramic decorations is used as an ASTM C777 test specimen. 

Data:

The specimen being tested, as well as the decorating substance utilized in ASTM C777, must be recognized. The degree of attack is graded according to the following visual test grades:

● No signs of an attack.
● When viewed at a 45° angle, there is an appearance of stain on the surface, although it is not visible if the angle is less than 30°.
● A distinct stain that does not distort reflected light.
● The surface is dull or matte, with the possibility of chalking.

Conclusion:

The ASTM C777 test method is used to measure the sulfide resistance of ceramic decorations on glass in order to ensure their vital durability.