An ESL cover plate is a porous, fired ceramic plate used to cover green
ceramic parts during firing. Porous alumina and zirconia plates find use in applications
such as the manufacture of SOFC and other fuel cell electrolyte substrates, MEA's,
interconnects, and other fuel cell assemblies.
The cover plate acts as a permeable flattening weight, reducing camber, warping or
bowing during the initial firing of the part, while retaining gas permeability
during organic removal. Use of a cover plate allows the replacement of a sintering
or subsequent flat firing with a single-step firing process, thus reducing energy
and other costs. The use of a porous weight or cover plate promotes
creep flattening during the initial sintering process, without the grain growth
experienced in a second firing. During this first firing a reduction in
substrate camber, edge curling and rippling can be expected.
The cover plate may also be used as a refractory setter liner to avoid impurities
from kiln or furnace furniture such as setters, saggars, batts or boats. Setter
liners extend the life of kiln furniture, for example in ferrite and thermistor
manufacturing. ESL cover plates can also find use as spacers between multiple
green ceramic parts in a sintered stack, thus increasing kiln loading.
Alumina cover plates can be used up to a maximum temperature of 1550°C, and are
re-usable, requiring only an occasional thermal re-flattening firing. Zirconia cover plates may be required when diffusion reactions or contamination by alumina is a possibility.
The data sheet (PDF file) gives details of the standard cover plate sizes currently
available, but customized dimensions are also offered. The trial quantity sample pack
available on this web site will include cover plates of several standard sizes. |
