On the morning of November 11th, we had the honor of inviting Professor Lu Zhenya to give a lecture entitled Electronic Ceramic Materials and Devices.

In the first part, Professor Lu introduced the basic information in electronic ceramic materials and components. Professor Lu first started from the electronic equipment and mobile phone in daily life. He subsequently introduced the current level of China's electronic components and compared the gap to that of the international developments. With the theory of energy band in solids, Professor Lu explained that the conductivity of solid materials depends on the size of the band. Metal materials without a energy band gap or with a small band are categorized as conductors; materials with a band width of more than 4 electron Volts are categorized as insulators; and materials with a narrow energy band are categorized as semiconductors, where electrons are excited into the conduction band and contribute to current conduction when the temperature rises. Finally, three types of ceramic materials were introduced, namely capacitor medium ceramic materials, iron voltage electrical ceramic materials and electronic sensitive ceramic materials.

In the following part, students learned more on the theories, research and applications of electronic ceramic materials as well as components nowadays.

Professor Lu talked about the relationship between electrical capacity as well as dielectric constant, and explained how the dielectric constant characterizes the degree of polarization of medium materials under electric fields. The greater the degree of polarization and the amount of charge, the greater the capacity. According to the relationship between electrical capacity and dielectric constant, Professor Lu proposed three methods of miniaturization of high capacity capacitors. Professor Lu also taught students ways to reduce costs by using base metal electrodes to make it more suitable for actual production.

For piezoelectric ceramic materials, Professor Lu first described what piezoelectric effect is. Piezoelectric effect is when some dielectrics are forced to deform in a certain direction, the two opposite surfaces become polarized and charged. Professor Lu explained that this characteristic is temperature-related, and that only specific temperatures exhibit ferroelectricity and piezoelectricity.

Then came the introduction of voltage-sensitive ceramic materials. This material presents an unusually large nonlinear relationship at high voltages - the voltage image, which can be utilised for overvoltage protection and absorption of overvoltage energy. 

Finally, Professor Lu showed several scientific research achievements, including anti-reductive medium materials for oxide capacitors, oxide pressure-sensitive ceramic materials, pressure-sensitive/ thermal components and so on. Professor Lu also encouraged students to participate in the scientific research of electronic materials and contribute to the development of the country. The lecture ended happily in a group photo. Students were very grateful to Professor Lu for his sharing.