Positive Temperature Coefficient （hereinafter referred to as：PTC）is a kind of semiconductor thermal ceramics. Its characteristic is sensitive to temperature. It shows negative resistance when it is lower than the Curie temperature; when it reaches the Curie temperature, its resistance value begins to increase sharply. When used as a heating material, it has the following superior characteristics: automatic constant temperature, no oxygen consumption, corrosion resistance, etc. PTC ceramics are mainly doped barium titanate semiconductor ceramics, which have relatively small ionization energy and can be thermally excited to generate conductive carriers at room temperature, thereby forming semiconductors.
High temperature co-fired alumina ceramic heating sheet, namely metal ceramics heater（hereinafter referred to as：MCH) uses high-temperature co-fired multilayer ceramic technology to print the heating resistor paste on the cast ceramic green body according to the design requirements of the heating circuit, and then multi-layers are combined and fired into a whole, so as to have corrosion resistance, high temperature resistance and longevity It has the advantages of long, high efficiency and energy saving, uniform temperature, good heat conduction, and fast thermal compensation. It does not contain harmful substances such as lead, mercury, and hexavalent chromium, and fully meets the EU environmental protection requirements.
The component heats the air directly: MCH has better air heating effect than PTC.
Electric heater heating air: The air heating effect of MCH electric heater is better than that of PTC electric heater. At low heat level, the maximum temperature of MCH can reach 115℃, while PTC is only 93℃. In the high-heat mode, the balanced power of MCH is only about 80% of PTC.
Electric heaters heating constant heat field pipes: Under the same conditions, when a fixed voltage is applied, the air heating effect of MCH electric heaters is better than that of PTC electric heaters.
Closed space heating test: In terms of power consumption, MCH saves energy by 24.59% compared to PTC.
Heating silicone oil comparison test: Use silicone oil as the heating and conduction medium to compare the heating performance and power consumption of PTC and MCH heating components. , Under the same conditions as other conditions, the heating effect of MCH heating element heating silicone oil is significantly better than that of PTC heating element under the premise of consuming the same power.
The above comparison shows that under the same test conditions, under the premise that the heating effect is better than the PTC heating component, the MCH heating component saves more than 20% energy than the PTC component.
The MCH heating sheet is a high-temperature co-fired multilayer metal-ceramic composite material. The heating metal paste layer is printed on the alumina ceramic green body as the insulating medium, and then another alumina ceramic green body is laminated on it. Co-fired into one. From the perspective of heating principle, the heating principle of MCH is metal tungsten conduction, and the high electrothermal conversion efficiency of metal tungsten is recognized. The nature of metal conduction is free electron conduction, and the outer layer of metal atoms has fewer electrons. After being combined into structural elements, atomic There are still more electron vacancies in the outer layer, which can accommodate foreign electrons to enter and move, so it is easy to conduct electricity.
PTC is essentially a semiconductor material. The principle of energization and heating is that a certain number of free electrons are formed by semiconductor doping. PTC is made of barium titanate as the matrix and doped with other polycrystalline ceramic materials, which has a low The resistance and semi-conductivity characteristics.
