ABSTRACT
Pyrometric cones (Figure 1.1) have been in common use over the past century in the manufacture of ceramic ware. They are a series of fired mixtures of ceramic materials pointing 8° from vertical, which "droop" after exposure to elevated temperatures for a period of time. The manufacturer [4] provides a series of sixty-four cone numbers ranging from 022 ( deformation at 576°C at a heating rate of 1°C/min) to 42 (over 1800°C). 3 By placing a series of cones near the firing ware in a kiln, the operator can determine when firing of the ware is complete, even when the furnace temperature is only loosely controlled. The refractories industry has made cone shapes out
of their materials and correlated the points of collapse under thermal processing to pyrometric cones, in order to designate their products with "pyrometric cone equivalents". Pyrometric cones are a prime example of the use of well characterized materials for the investigation and optimization of other materials. While seeming more elegant, thermoanalytical instruments are based on the same principle.
