Refractory Technology
Zirconia refractories are not used in

High frequency induction furnaces in the form of inductors
Lining high temperature ceramic kilns
Furnaces subjected to fluctuating temperature
Making sheaths for thermocouple

ANSWER DOWNLOAD EXAMIANS APP

Refractory Technology
Natural silica

Is not stable at high temperature
Mainly contains quartz
All of these
Transforms to other allotropic forms i.e tridymite and cristoballite involving very high volume changes

ANSWER DOWNLOAD EXAMIANS APP