Thick film heaters are typically made from a ceramic or stainless steel substrate with a thick film of conductive material such as a metal oxide or carbon-based ink printed onto its surface. The properties of both the ceramic substrate and the conductive material can affect the performance and efficiency of the heater in various ways.
- Thermal conductivity of the ceramic substrate: The thermal conductivity of the ceramic substrate affects the rate at which heat is transferred from the conductive layer to the environment. A substrate with high thermal conductivity would transfer heat more efficiently, resulting in faster heating times and higher efficiency.
- Coefficient of thermal expansion (CTE) of the ceramic substrate: The CTE of the substrate determines how much it expands or contracts with changes in temperature. If the CTE of the substrate is mismatched with that of the conductive layer, it can cause delamination and cracking, leading to reduced efficiency and shorter lifespan.
- Conductivity of the conductive material: The conductivity of the conductive layer affects the rate at which heat is generated and transferred to the environment. A material with high conductivity would generate more heat for a given amount of input power, resulting in higher efficiency.
- Adhesion strength between the conductive layer and substrate: The adhesion strength between the conductive layer and substrate affects the durability and lifespan of the heater. A weak adhesion can lead to delamination and reduced efficiency over time.
- Temperature coefficient of resistance (TCR) of the conductive material: The TCR of the conductive layer determines how its resistance changes with temperature. A material with a high TCR would have a larger change in resistance with temperature, which could be used to provide temperature control or temperature sensing.
Overall, the properties of the ceramic substrate and conductive material used in thick film heaters can affect their performance and efficiency in various ways, and careful selection of materials is important for optimal design.
