Water-Quench Thermal Shock Testing for Ceramic Disks.

Thermal shock resistance of core reinforced all-ceramic crown systems.

The coefficient of thermal expansion of core and veneer porcelains for all ceramic crowns must be compatible to prevent formation of stresses during the firing cycles. The purpose of this study was to use a thermal shock test to evaluate the crazing resistance of six all-ceramic crown systems. The systems tested were: Vita In-Ceram, Vita Hi-Ceram, Dicor veneered with Vitadur N, magnesia core ve...

Thermal shock and thermal fatigue study of ceramic materials on a newly developed ascending thermal shock test equipment

A test equipment was designed to study thermal shock and thermal fatigue of ceramic materials subjected to fast heating (ascending). The equipment was designed to generate thermal stress in a test specimen by heating one surface of it by an oxy-hydrogen flame while cooling the opposite surface. The sample cracked when thermal stress exceeded its mechanical strength. The in situ crack formation ...

THERMAL SHOCK OF REFRACTORIES

Being brittle and having low thermal conductivity, refractories suffer damage and sometimes fail in service as a result of thermal shock. While the approach of those making fine-grained technical ceramics is to make their products sufficiently strong to withstand thermal stresses the refractory technologist is more cunning. He uses, often little known, devices to provide resistance to thermal s...

Design of water shock tube for testing shell materials

Ceramic Disks as Efficient and Robust Cathodes

Electron emission from ceramic disks depends strongly on the shape of the front electrode. The common interconnected grid is not good for a stable emission. An electrode consisting of an ensemble of metal point-like islands within a metal ring leads to quite a stable emission. In the first case the sandwich of the continuous electrode (on one surface) and the grating (on the front surface) cons...