Silicon nitride (Si3N4) ceramics offer some of the best-in-class tribological properties, with outstanding nominal fracture toughness (Syalon 101 = 7.7 MPa m1/2) and exceptional strength characteristics (compressive, flexural, etc.). This combination makes silicon nitride ideal for precise wear applications where components are subjected to significant ongoing stress throughout service: dies, weld rolls, and cutting tools for example.
The mechanical properties of silicon nitride ceramics are typically matched by high thermal capabilities (Syalon 101 thermal shock resistance ΔT = 900°C) and good corrosion resistance, providing fully-rounded performance in demanding industrial environments. In fact, the ceramic has been engineered to exceed long-serving industry-standard materials like alumina (Al2O3) and tungsten carbide (WC) in severe wear applications where corrosion and temperature are consistent concerns. Ceramic nozzles typify these sorts of conditions.
This post will explore the benefits of silicon nitride nozzles in blasting, extrusion, and gas/fluid flow applications.
Sandblasting with Silicon Nitride
Sandblasting – also referred to as grit or shot blasting – is the process of deliberately wearing away a surface using a jet of highly pressurized particulate material. As the name suggests, sand has been used in the past, but the hazards of free silica and poor recyclability have largely consigned silica-based abrasive media to history. Today, sandblasting is more commonly carried out using a choice of finely engineered abrasive particles; often brown-fused alumina.
Silicon nitride shot blasting nozzles are beneficial over conventional tungsten carbide nozzles due to their material properties thanks to a covalently bonded crystalline or semi-crystalline atomic structure. With a completely impermeably structure (0% porosity), silicon nitride nozzles can withstand abrasion from even the smallest hard-wearing particles for up to 1,000 hours of continuous operation.
Silicon Nitride Extrusion Nozzles
Nozzles are often used to draw material through an extrusion system towards the extrusion die downstream, where the flow is converted into a near-net shape. The challenges faced by nozzles in extrusion processes vary depending on the method (hot, cold, warm, friction, etc.) and the properties of the blank material.
Silicon nitride nozzles are particularly useful in hot extrusion systems where metals and alloys are pushed through the system at temperatures exceeding their recrystallization point. With maximum use temperatures of up to 1200°C (2192°F), silicon nitride nozzles are uniquely capable of facilitating high throughput extrusion for various metals and alloys with minimal degradation over time.
Flow Control with Silicon Nitride
Ceramic nozzles are often used in the petrochemical sector to control the flow of various challenging substances (acids, slurries, etc.) with regards to direction, mass, pressure, speed, or shape. The potential uses of these components are incredibly wide-ranging. They may be connected to subsea hydro cyclones to control the rate of flow for extracted slurries, or for metering of precursors and raw materials in chemical blending processes.
Silicon nitride ceramics offer one of the widest range of resistances to common chemicals and chemically-corrosive elements. They are proven to withstand chemical attack from acids and alkalis (hydrochloric acid, sulphuric acid, sodium hydroxide, etc.), alongside corrosive fumes (chlorine), providing superior chemical stability for increased length of service.
International Syalons: Expert Silicon Nitride Suppliers
International Syalons specializes in the generation of high-performance technical ceramics for demanding industrial applications. With a proprietary range of silicon nitride-based ceramics tailored for distinct mechanical, chemical, and electrical properties, we are confident that we can provide you with a material solution that meets your needs.