What is piezoelectric ceramic? And The process flow of piezoelectric ceramic.

Piezoelectric ceramic is a functional pzt ceramic material that can convert mechanical energy and electrical energy to each other. The so-called piezoelectric effect means that when some medium is subjected to mechanical pressure, even if this pressure is as small as sound wave vibration, it will produce compression or elongation and other shape changes, causing the medium surface to be charged. This is a positive piezoelectric effect piezo ceramic cylinder. Conversely, when an exciting electric field is applied, the medium will be mechanically deformed, called the inverse piezoelectric effect. This wonderful effect has been applied in many fields closely related to people's lives to achieve energy conversion, sensing, driving, frequency control and other functions.

General process flow of piezoelectric ceramic transducer:

(1) Ingredients: carrying out pre-treatment of the materials, remove impurities and remove moisture, and then weigh various raw materials according to the proportion of the formula. Note that a small amount of additives should be placed in the middle of the large materials.
(2) Mixing and grinding: The purpose is to mix and grind all kinds of raw materials, and prepare the conditions for complete solid phase reaction for calcination. Generally, dry or wet grinding is adopted. Dry grinding can be used for small batches, and agitation ball milling or air flow crushing can be used for large batches, with higher efficiency.
(3) Pre-firing: The purpose is to perform solid-phase reaction of each raw material at high temperature to synthesize piezoelectric ceramics. This process is very important and will directly affect the sintering conditions and the performance of the final product.
(4) Secondary fine grinding: The purpose is to re-finely mix the pre-fired piezoelectric ceramic powder and finely grind it, so as to lay a solid foundation for uniform porcelain formation and consistent performance.
(5) Granulation: The purpose is to make the powder form high-density and fluid particles. The method can be carried out manually but with low efficiency. The current efficient method is spray granulation. In this process, a binder is added.
(6) Forming: The purpose is to compact the granulated material into the required prefabricated blank.
(7) Plastic discharge: The purpose is to remove the binder added during granulation from the blank.
(8) Sintering into porcelain: The blank is sealed and sintered into porcelain at high temperature. This link is quite important.
(9) Shape processing: Grind the burnt products to the required finished size.
(10) The target electrode: set a conductive electrode on the required ceramic surface. The general methods are silver layer infiltration, chemical deposition and vacuum coating.
(II) High voltage polarization: Orient the internal electric domains of the ceramic, so that the ceramic has piezoelectric properties.
(12) Aging test: Check the indicators after the piezo ceramic performance is stable to see if it meets the expected performance requirements.

In 1880, the French Curie brothers discovered the "piezoelectric effect." In 1942, piezoelectric ceramic material barium titanate was made in the United States, the Soviet Union, and Japan. In 1947, the barium titanate pickup, the first piezoelectric ceramic device, was born. In the early 1950s, another piezoelectric ceramic material with much better performance than barium titanate, lead zirconate titanate, was successfully developed. Since then, the development of piezoelectric ceramics has entered a new stage. From the 1960s to the 1970s, piezoelectric ceramics continued to improve and became perfect. For example, lead zirconate titanate binary piezoelectric ceramics improved with multiple elements, and ternary and quaternary piezoelectric ceramics based on lead zirconate titanate also came into being. These materials have excellent performance, simple manufacture, low cost and wide application.

Piezoceramic's sensitivity to external forces makes it even sense the perturbation of flying wings by dozens of meters away from the air, and convert extremely weak mechanical vibrations into electrical signals. Using this characteristic of piezoelectric ceramics, it can be applied to sonar systems, meteorological detection, telemetry environmental protection, household appliances, etc.
Nowadays, piezoelectric ceramics have been applied by scientists in national defense construction, scientific research, industrial production, and many fields closely related to people's lives. They have become versatile in the information age.

In the aerospace field, piezoelectric gyros made of piezoelectric ceramics are the "rudder" of spacecraft and artificial satellites flying in space. Relying on the "rudder", spacecraft and artificial satellites can guarantee their established orientation and course. Traditional mechanical gyros have short lifespan, poor accuracy, and low sensitivity, which can not meet the requirements of spacecraft and satellite systems. However, the compact piezoelectric gyros have high sensitivity and good reliability.