Piezoelectric ceramic manufacturing process

Piezoelectric ceramic manufacturing process

The process flow chart is as follows: Ingredients-mixing grinding-pre-sintering-secondary grinding-granulation-molding-plastic ejection-sintering into porcelain-shape processing-electrode-high voltage polarization --Aging test.

1. Ingredients: Carry out the pre-treatment of the materials to remove impurities damp, then weigh various raw materials according to the formula ratio, paying attention to a small amount of additives to be placed in the middle of the bulk.

2. Mixing grinding: The purpose is to mix grind various raw materials to prepare conditions for complete solid-phase reaction for pre-burning. Generally, dry grinding wet grinding is adopted. Dry milling can be adopted for small batches, agitating ball milling jet milling can be adopted for large batches, which has higher efficiency.

3. Pre-sintering: The purpose is to perform solid-phase reaction of each raw material at high temperature to synthesize piezoelectric ceramics. This process is very important. It will directly affect the sintering conditions the performance of the final product.

Fourth, the second fine grinding: the purpose is to finely vibrate mix the pre-fired piezoelectric ceramic powder, so as to lay a solid foundation for the uniform performance of porcelain.

5. Granulation: The purpose is to make the powder form high-density particles with good fluidity. The method can be carried out manually but the efficiency is low. An effective method is to use spray granulation. Adhesive is added in this process.

6. Forming: The purpose is to compact the pelletized material into a blank of the required prefabricated size.

7. Plastic ejection: the purpose is to remove the binder added during granulation the blank.

8. Sintering into porcelain: the blank is sealed sintered into porcelain at high temperature. This link is very important.

9. Shape processing: Grind process the burned products to the required finished size.

X. Electrode: Set a conductive electrode on the required ceramic surface. General methods include silver layer burning infiltration, chemical deposition vacuum coating.

11. High-voltage polarization: Orientation of the electrical domains inside the ceramic, so that the ceramic has piezoelectric properties.

12. Aging test: After the ceramic performance is stable, check the various indicators to see if the expected performance requirements are met.

The manufacturing feature of piezoelectric ceramics is to polarize ferroelectric ceramics under a DC electric field to make them have piezoelectric effect. Generally, the polarization electric field is 3～5kV/mm, the temperature is 100～150°C, the time is 5～20min. These three are the main factors affecting the polarization effect. Piezoelectric ceramics with better performance, such as lead zirconate titanate ceramics, have electromechanical coupling coefficients as high as 0.313 to 0.694.