Messi Biology Co., Ltd. states that magnesium carbonate, as one of the additives for electronic ceramics, plays a significant role in optimizing the dielectric properties of ceramic materials. Dielectric properties primarily include key parameters such as dielectric constant, dielectric loss, and temperature stability, which directly affect the application performance of ceramic materials in electronic devices like capacitors, microwave devices, and high-frequency components.
1. Effect of Magnesium Carbonate on Dielectric Constant
The dielectric constant determines a material’s ability to store electrical charge, and a higher dielectric constant generally improves the performance of electronic components. The influence of magnesium carbonate on the dielectric constant is mainly reflected in the following aspects:
- Promoting Grain Growth: During ceramic sintering, magnesium carbonate decomposes into magnesium oxide at high temperatures. Magnesium oxide can promote the growth of ceramic grains, and larger grains typically help increase the dielectric constant. For example, in barium titanate-based ceramics, an appropriate amount of magnesium carbonate helps increase grain size, raising the dielectric constant and making the ceramic material more suitable for high-dielectric capacitors.
- Adjusting Crystal Phase Structure: Mg²⁺ ions can partially substitute metal ions in certain ceramic materials, leading to changes in the crystal phase structure, thereby affecting the dielectric constant. For instance, in lead zirconate titanate (PZT) piezoelectric ceramics, Mg²⁺ doping affects lattice distortion, optimizing the material’s dielectric properties.
- Suppressing Dielectric Dispersion: Dielectric dispersion refers to the phenomenon where a material’s dielectric constant varies with frequency. The addition of magnesium carbonate can reduce grain boundary defects, decrease dielectric dispersion at high frequencies, and improve the stability of the dielectric constant.
2. Effect of Magnesium Carbonate on Dielectric Loss
Dielectric loss represents the energy dissipation of a material under an electric field. The lower the loss, the better the material’s performance at high frequencies. Magnesium carbonate can reduce dielectric loss through the following ways:
- Reducing Grain Boundary Defects and Impurities: Magnesium oxide formed after the decomposition of magnesium carbonate can effectively reduce grain boundary defects and excess impurities, lowering dielectric loss and improving the material’s insulation performance. For example, in high-frequency ceramic materials such as lithium niobate and lithium tantalate, an appropriate amount of magnesium carbonate can reduce dielectric loss, leading to better performance in wireless communication equipment.
- Improving Sintering Density: High-density ceramic materials generally have lower dielectric loss, and magnesium carbonate can promote ceramic sintering, increasing the material’s density. For instance, in alumina-based ceramics, magnesium carbonate helps reduce porosity, improving the material’s electrical stability and low-loss characteristics.
- Reducing Electrical Conductivity, Enhancing Insulation: Magnesium carbonate can reduce the concentration of free charge carriers in ceramic materials, lowering electrical conductivity and thereby reducing dielectric loss. This is crucial for high-frequency electronic devices, such as RF components and microwave devices.
3. Effect of Magnesium Carbonate on Temperature Stability
The dielectric properties of electronic ceramics change with temperature, thus it’s necessary to ensure their stability under various temperature conditions. Magnesium carbonate can enhance the material’s temperature stability through the following methods:
- Reducing the Coefficient of Thermal Expansion: The addition of magnesium oxide can effectively reduce the thermal expansion coefficient of ceramics, making the material less prone to deformation or cracking in high-temperature environments. For example, in magnesium aluminate-based ceramics, the role of magnesium carbonate reduces its thermal expansion coefficient, thereby improving temperature stability.
- Adjusting Curie Temperature: In barium titanate-based ceramics, Mg²⁺ doping can adjust the material’s Curie temperature, allowing its dielectric constant to remain stable over a wider temperature range.
- Preventing Dielectric Fluctuations Caused by Phase Transitions: In certain ferroelectric ceramics (such as Pb(Zr,Ti)O₃), magnesium carbonate can reduce phase transition behavior at high temperatures, preventing dielectric fluctuations caused by phase transitions and enhancing the reliability of the ceramic.