It is often possible to improve the performance by changing one or more of these but as with all ceramic applications thermal shock is only part of the equation and changes must be looked at in context of all the performance requirements.
With the current state of the industrial economy around the world this is an ideal time to consider the use of alternative materials for your applications and processes. Industrial ceramic materials, for example, offer a vast array of compositions and performance characteristics and can be a cost effective alternative in many harsh environments such as high temperature, electrical resistance, wear applications and chemical contact.
The link between metals and ceramics is a long one. Archaeologists have found evidence linking the use of ceramics to contain molten metal as far back as 6000BC. Ceramic containers (Alumina and Zirconia Crucibles) continue to be used to this day.
Measurement of high temperatures, greater than 1000 C, using ceramic based thermocouples is a well established process. In order to do this successfully the resistance wires within the thermocouple need to be insulated and protected.
Lava, known scientifically as Pyrophyllite, is one of the most promising natural solid materials in the world of industrial ceramics as a substitute to Steatite. Pyrophyllite can be used by customers who are in need of precision machined parts of Steatite in very small volumes for stocks, prototyping, and machinery, where it is not economically viable to manufacture the tooling necessary to produce the steatite parts. This material would an ideal substitute, primarily due to its similar properties, to Steatite. The fact that Pyrophyllite can withhold a maximum temperature of 1300oC as a refractory part means that it would be ideal for furnace parts. Lava is also capable of withstanding up to 700oC as an electrical insulator. Similarly to Steatite, it also starts to show leakages in electrical current at temperatures above700oC through a decrease in insulation.Although many of the mechanical, electrical and thermal properties are similar for both Lava and Steatite, this does not necessarily mean that the reactionary corrosion of each material will be the same. This is primarily due to the different chemical compositions of the two materials. These are because while Steatite is 65% SiO2 with 34% MgO, Lava has got 60% SiO2 with 35% Al2O3. These different compositions may result in two different reactions to the environment where the part is to be used.