Automotive Industry

Four advanced ceramics—Alumina (Al₂O₃), Zirconia (ZrO₂), Silicon Carbide (SiC), and Silicon Nitride (Si₃N₄)—are penetrating from traditional components into core electric drive and battery systems thanks to their unique properties, becoming key enabling materials driving this transformation.

In the automotive sector, the core value of these ceramic materials lies in addressing the challenges posed by high temperatures, high wear, high corrosion, and electrification:

• High-temperature resistance and thermal management: They can operate at temperatures far exceeding the extremes of metal, and silicon carbide exhibits excellent thermal conductivity.
• High wear resistance and low friction: They significantly extend the life of components under frictional conditions.
• Excellent electrical properties: From insulators to semiconductors, they meet the high-voltage insulation and high-frequency switching requirements of automotive electrification.
• Chemical inertness: They are corrosion-resistant and can withstand a variety of harsh liquid and gas environments.
• Lightweight: Their lower density than metal helps reduce the mass of moving parts and improve efficiency.

1. Alumina (Al₂O₃) - "A Reliable Insulator and Wear-Resistant Guardian"
This cost-effective and widely used industrial ceramic primarily leverages its insulation, wear resistance, and corrosion resistance in automobiles.
Advantages: High insulation, good wear and corrosion resistance, and relatively low cost.
Specific Applications:

• Sensor Substrates and Packaging: Ceramic substrates for oxygen sensors, knock sensors, and pressure sensors, protecting the sensitive components within.
• Spark Plug Insulators: Core components requiring extremely high insulation and thermal shock resistance under high voltage.
• Wear-Resistant Components: Mechanical seals in water pumps and transmissions, preventing leakage and extending service life. 
• Window Materials: Serves as a protective window for rearview cameras and radar sensors (such as millimeter-wave radars), minimizing the impact on signal penetration.

2. Zirconia (ZrO₂) - "Tough Sensing and Actuation Expert"
Leverages its high toughness, low thermal conductivity, and unique electrical properties.
Advantages: Extremely high fracture toughness, low thermal conductivity (thermal insulation), ionic conductivity, and high wear resistance.

Specific Applications:

• Oxygen Sensors: Core functional material. Utilizing the oxygen ion conductivity of yttria-stabilized zirconia (YSZ) at high temperatures, sensors are manufactured to detect oxygen concentration in exhaust gases, serving as the "eyes" of the engine's electronic control system.
• Piezoelectric Ceramics: Lead zirconate titanate (PZT)-based piezoelectric ceramics are widely used in fuel injectors (piezoelectric common rail systems, enabling more accurate and rapid fuel injection) and ultrasonic sensors (reversing radar and autonomous driving perception systems).
• Wear-resistant Structural Parts: Such as high-performance ceramic bearings, used in specialized operating conditions.

3. Silicon Carbide (SiC) - "The Chip and Thermal Management Core of the Electric Revolution"
The king of wide-bandgap semiconductors, it is the core "chip-level" material for electric vehicle electric drive systems and also has applications in the friction field.
Advantages: Wide-bandgap semiconductor properties (high-voltage/high-temperature/high-frequency resistance), extremely high thermal conductivity (excellent heat dissipation), high hardness, and low power consumption.

Specific Applications:

• Electric drive system main inverter: This is its most core and highest-value application. SiC MOSFETs replace traditional silicon-based IGBTs, improving inverter efficiency by several percentage points. This means significantly increasing driving range with the same battery capacity, or supporting higher charging power (800V platform), shortening charging time.
• On-Board Chargers (OBCs) and DC-DC Converters: Similarly, leveraging its high-frequency and high-efficiency characteristics, OBCs and DC-DC converters can be made smaller, lighter, and more efficient.
• Braking Systems: Carbon-ceramic brake discs (C/SiC composite materials) used in high-performance sports cars offer excellent thermal decay resistance, impact resistance, and lightweight advantages. Engine Turbochargers: Create lightweight turbine rotors, reduce rotational inertia, and minimize turbo lag.

4. Silicon Nitride (Si₃N₄) - "The Unsung Hero of High-Speed Power and Long-Endurance"
This ceramic offers the best overall mechanical properties, particularly suited for high-speed, high-stress, and long-life applications.

Advantages: High fracture toughness, low density, excellent thermal shock resistance, high hardness, self-lubrication, and long rolling contact fatigue life.

Specific Applications:

• New Energy Vehicle Bearings: This is a signature application. Full-ceramic or hybrid ceramic bearings (Si₃N₄ rolling elements) are used in electric drive spindles. Compared to traditional steel bearings, they are lighter (reducing centrifugal force), more resistant to high speeds, more insulated (preventing shaft current corrosion), and resistant to oil starvation conditions, significantly improving the speed, efficiency, and reliability of electric drives.
• Turbocharger Rotors: Their low density and high strength make them ideal for turbine rotors, significantly reducing turbo lag and improving engine responsiveness. 
• Spark plug insulators: Used in some high-performance engines, their thermal shock resistance is better than alumina.