Potter, AR and Austin, JC and Ormerod, RM and Haycock, PW and Heywood, BR and George, SD, X-ray images of defect formation in porcelain ceramics during drying, NDT and E International, 36, (2) pp. 77-83. ISSN 0963-8695 (2003) [Refereed Article]
The drying phase during the manufacture of ceramic pieces is often the point of failure owing to the formation of cracks. In this study, non-destructive microfocus X-ray imaging has been employed to study the onset of cracking in porcelain and correlate it with the moisture content. Samples of moist porcelain paste were extruded through dies of 30 and 50mm diameter. Sections of the extrudate were placed into an X-ray transparent oven and imaged while drying at constant temperature and low humidity. The time to the onset of cracking was found to be a function of temperature. The mode of failure was consistent across the temperature range 40-120°C.
The higher the drying temperature, the shorter the time to failure and the higher the moisture loss at failure. For a particular paste consistency and sample geometry there was found to be a critical moisture content below which cracking began to occur. This moisture threshold was observed to be weakly temperature dependent; it appears to be more sensitive to sample geometry and paste consistency. A safe drying curve has been constructed which provides a boundary for the process parameters which prevent cracking. The implication is that during the drying of a ceramic piece, different sections may have different safe parameter boundaries and the process must be designed to keep all sections within the safe region.
|Item Type:||Refereed Article|
|Keywords:||defect detection, radiographic images, X-ray imaging|
|Research Division:||Chemical Sciences|
|Research Group:||Physical Chemistry (incl. Structural)|
|Research Field:||Structural Chemistry and Spectroscopy|
|Objective Division:||Expanding Knowledge|
|Objective Group:||Expanding Knowledge|
|Objective Field:||Expanding Knowledge in the Chemical Sciences|
|Author:||Heywood, BR (Professor Brigid Heywood)|
|Web of Science® Times Cited:||7|
|Deposited By:||Research Division|
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