Material Characteristics:
Silicon nitride bonded silicon carbide ceramic is a new type of composite structural ceramic produced by using high-purity silicon carbide as the aggregate and silicon nitride as the bonding phase, formed and then reaction-sintered in a nitrogen-protected high-temperature furnace. With SiC content ≤75% and Si₃N₄ content ≥25%, it combines the high-temperature strength and high thermal conductivity of silicon carbide with the high toughness, thermal shock resistance, and wear resistance of silicon nitride. The material features a dense structure, low apparent porosity, and a low thermal expansion coefficient. It resists oxidation, softening, and deformation, and also possesses good high-temperature electrical insulation properties. It is a new type of high-performance protection tube material designed for demanding conditions such as high-temperature temperature measurement and atmosphere control.

Product Information:
Silicon nitride bonded silicon carbide protection tubes are single-end closed or double-end open tubes made from highly homogeneous tubular green bodies formed by extrusion or cold isostatic pressing, followed by densification through high-temperature nitridation reaction sintering. Giving full play to the combined advantages of high strength, excellent thermal shock resistance, dense structure, and corrosion resistance of the composite material, these protection tubes exhibit outstanding characteristics of no bursting, no permeation, erosion resistance, and excellent long-term gas tightness in harsh environments such as high-temperature molten metal and corrosive atmospheres.

Performance Parameters:
Bulk density: 2.7–2.85 g/cm³, apparent porosity ≤1%, flexural strength at room temperature ≥180 MPa, Vickers hardness ≥2500 HV, fracture toughness ≥4.0 MPa·m^1/2, coefficient of thermal expansion: 4.8×10⁻⁶ /K, maximum operating temperature: 1450 °C.

Product Dimensions:
Conventional protection tubes cover outer diameters from 10 mm to 80 mm, inner diameters from 6 mm to 65 mm, lengths from 200 mm to 2000 mm, and wall thicknesses from 2 mm to 15 mm. The standard product configuration is a single-end closed blind tube, while double-end open through tubes can also be fabricated. Further processing such as precision grinding of inner and outer diameters, hemispherical or flat bottom end finishing, end chamfering, radial slotting, and multi-step machining can be carried out. Yuko Corporation can also customize non-standard outer diameters, variable-diameter tubes, tubes with flanges, and multi-core assembled protection tube components according to customer drawings and requirements.

Product Applications:
Silicon nitride bonded silicon carbide protection tubes are widely used as atmosphere protection tubes and temperature measurement protection tubes in sintering kilns for lithium battery cathode and anode materials, thermocouple protection tubes in sintering furnaces for electronic ceramics and magnetic materials, temperature measurement protection tubes for non-ferrous metal smelting, protection tubes for powder metallurgy sintering furnaces, and temperature measurement and gas purge protection sheaths in environments with high-temperature melts or corrosive atmospheres in the chemical, glass, and other industries. They are a new type of composite ceramic protection tube that replaces traditional alumina or metal protection tubes, achieving higher temperature measurement accuracy and longer service life.