A lead free, thick film heating element. Known thick film heating elements
contain environmentally hazardous material such as lead. This is
particularly problematic when manufacturing thick film heating elements,
as lead is often used in thick film formulations to allow the glass-based
thick film to be processed at low firing temperatures. Using composite
sol gel technology, the present invention provides a method to produce a
lightweight mica-based thick film heating element based on thick film
materials that are free from lead or cadmium. This mica-based element is
lightweight, has the performance advantages of a thick film heating
element, and may be processed at a low temperature using thick film
materials. Particularly, the present invention provides a lightweight
heating element comprised of a mica-based substrate material, a resistive
thick film that can be produced by composite sol gel technology,
optionally a conductive thick film which is used to make electrical
connection to the resistive element, and optionally a topcoat which is
used to provide protection against moisture and oxidation. This element
is lightweight, provides efficient, rapid heat up and cool down, can be
designed to provide even temperature distribution, and delivers power at
lower operating temperatures resulting in increased element safety.