Silicon Nitride Guide Roller

Exceptional Mechanical Properties

One of the standout attributes of the Silicon Nitride Guide Roller is its exceptional mechanical properties. Boasting a very low density of 3.2~3.25 g/cm³, this material is both lightweight and immensely strong. This makes the Silicon Nitride Guide Roller ideal for applications where weight is a critical factor without compromising on durability. The high hardness rating of HRA 92~94 ensures that the rollers are incredibly resistant to wear and abrasion, making them suitable for environments subjected to continuous friction and pressure.

The fracture toughness, rated between 6 to 8 MPa·m1/2, demonstrates the material’s capacity to endure significant mechanical stress without cracking. Moreover, the bending strength of ≥ 900 MPa ensures that these rollers can maintain their structural integrity even under substantial loads, further highlighting their robustness.

Superior Thermal Characteristics

Thermal management is a critical aspect of many industrial applications, and Silicon Nitride Guide Rollers excel in this domain. Capable of operating at temperatures as high as 1300~1600°C, the Silicon Nitride Guide Roller is well-suited for high-temperature environments. Their excellent thermal shock resistance, characterized by high thermal stress parameters, ensures that the Silicon Nitride Guide Roller can withstand rapid temperature fluctuations without incurring damage.

Additionally, the low thermal conductivity of 23-25 W/(m·K) makes these rollers proficient in insulating heat, thereby protecting other system components from thermal stress. This feature is particularly advantageous in industries such as metal processing and semiconductor manufacturing, where precise thermal control is paramount.

Chemical Resistance and Durability

Silicon Nitride Guide Rollers exhibit remarkable chemical stability. They are resistant to reaction with most inorganic acids, with hydrofluoric acid being a notable exception. This chemical inertness extends their lifespan even in harsh chemical environments, making the Silicon Nitride Guide Roller suitable for use in sectors such as chemical processing, pharmaceuticals, and food production.

Types of Silicon Nitride Ceramics

Semicorex offers two primary types of Silicon Nitride ceramics for their guide rollers: Gas Pressure Sintered Silicon Nitride (GPSN) and Hot Pressed Silicon Nitride (HPSN). Each type is designed to provide specific benefits based on the application requirements.

Gas Pressure Sintered Silicon Nitride (GPSN): The GPSN method involves mixing silicon nitride powder with sintering aids to promote liquid phase sintering, along with binders to enhance the mechanical strength of the green ceramic body. The powder is then pressed into the desired shape, and green-machining can take place. The compacts are placed into a furnace with a pressurized nitrogen atmosphere to aid in densification and prevent the evaporation or decomposition of silicon, nitrogen, and additives. This process results in a highly dense and uniformly structured material, offering superior performance in demanding applications.

Hot Pressed Silicon Nitride (HPSN): HPSN is produced by uniaxially pressing silicon nitride powder (with sintering additives) while simultaneously applying heat. This process requires a specialized press and die, resulting in silicon nitride with excellent mechanical properties. However, only simple shapes can be produced through this method. Since it is impossible to green-machine a component that is hot-pressed, diamond grinding is the only way to create complex geometries. Due to the high costs and challenges associated with diamond grinding and hot-pressing, the use of HPSN is typically limited to the production of simple components in small quantities.

SEM-SE images of Si3N4 ceramic at a 5000 × and b 30,000 × magnifications, c pore size distribution and d XRD pattern of Si3N4 sample