Thermal shock resistance Subject

Thermal Expansion and Thermal Shock Resistance In many situations it is difficult to directly substitute silica brick for red shale or fireclay. Changes in design might be needed to avoid subjecting the silica brick to destructive tensile or shear stresses during operation because of expansion differences. The thermal expansion of the specialty type silica product (Type 2) is much less than that of acid brick. The vitreous silica material which contains some crystalline Si02 (Type 1) has a thermal expansion that closely matches that of acid brick at temperatures less than 800°F. Above that temperature, the expansion is much less. 

The thermal shock fracture behavior of ceramics has been investigated using traditional testing methods such as the water quench in which the critical temperature difference, where samples are subjected to severe damage, is used as the thermal shock resistance. Recently, new experimental methods are proposed and applied to the investigation of macroscopic crack propagation process during thermal shock fracture, based on fracture mechanics. ... 

Glass offers good resistance to strong acid at high temperatures. However, it is subject to thermal shock and a gradual loss in integrity as materials such as iron and siUca are leached out into the acid. Nonmetallic materials such as PTFE, PVDC, PVDF, and furan can be used for nitric acid to a limited degree, but are mainly restricted to weak acid service at ambient to moderate temperatures. 

Zirconia Refractories. The most common zirconia-containing refractories are made from zircon sand and are used mosdy for container glass-tank subpaver brick. Refractory blocks made from a composition of zircon and alumina, used to contain glass melts, are generally electromelted and then cast. These exhibit excellent corrosion resistance but are subject to thermal shock. Refractories made from pure Zr02 are extremely expensive and are... 

There is no evidence of delamination, corrosion, or other visual changes for TFML structures subjected to MIL-STD-883C tests for temperature cycling (-65°C to 150 C, 100 cycles), thermal shock (-55°C to 125°C, 15 cycles), moisture resistance (Method 1004.5), and accelerated aging at 85 C/85 percent r.h. for 1000 hours (unpublished results) ... 

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