Acoustic Emission from a Porcelain Body during Cooling

• Published in: Journal of the American Ceramic Society Vol. 82; no. 2; pp. 445 - 448
• Main Authors: Ohya, Yutaka, Takahashi, Yasutaka, Murata, Minori, Nakagawa, Zenbe-e, Hamano, Kenya
• Format: Journal Article
• Language: English
• Published: Westerville, Ohio American Ceramics Society 01.02.1999; Blackwell; Wiley Subscription Services, Inc
• Subjects: Applied sciences; Building materials. Ceramics. Glasses; Ceramic industries; Chemical industry and chemicals; Exact sciences and technology; Heavyclay products, whiteware; Miscellaneous; Porcelain; Cooling; Acoustic emission; Cracking; Manufacturing; Experimental study; Microstructure; Quartz; Ceramic materials
• ISSN: 0002-7820; 1551-2916
• DOI: 10.1111/j.1551-2916.1999.tb20083.x

Quartz grains in porcelain bodies cause cracking. Under the present conditions, acoustic emission (AE) has shown that the cracking occurred in a temperature range of 900°–800°C during cooling from firing at a temperature of 1200°C. This cracking can be explained by a large thermal expansion mismatch that was due to the negative thermal expansion of quartz at temperatures >1000°C and no stress relaxation of the glass phase. At a temperature of 573°C, which is the transition temperature of quartz, AE was not detected by the measuring system that was used, although there were many peripheral cracks around the large quartz grains. The energy release rate of the peripheral cracks at a temperature of 573°C was too low to be detected by the equipment that was used.