Ads by Google
Jinyu SI3N4 Silicon nitride thermocouple protection sheaths ( protective tube) is formed by CIP biscuit, then machined to accurate dimension, and put it into Reaction-Sintered furnace for sintering. The special ceramic products by this modern advanced craft have the characteristics of high and equal density, good dimensional accuracy , etc. Silicon nitride is especially suitable for thermocouple protection tube measuring temperature of molten aluminum for its anti-fusion.
Silicon nitride ceramics possess excellent properties of high thermal stability, antioxidant capacity and good dimensional precision of products. As silicon nitride is covalent compounds with high bond energy and can form protective film of oxide in the air, so its good chemical stability can make silicon nirtide not be oxidized below 1200°C, and generate protective film to prevent further oxidation between 1200~1600°C. Silicon nitride can not be infiltrated and corroded by aluminium, lead, tin, silver, brass, nickel and other molten metals, but can be corroded by molten metal like magnesium, nicochrome and stainless steel.
Reaction bonded silicon nitride is made by direct nitridation of a compacted silicon powder, and because of the difficulty of ensuring complete reaction; it is hard to achieve a high component density. Usual densities are in the range 2.3 – 2.5g/cm3 compared with 3.29g/cm3 for gas pressured sintered silicon nitride. The higher density gives the HPSN, SSN & GPS-SSN materials better physical properties and means they are used in more demanding applications at very high temperature, especially for non-ferrous molten metal handling and thermocouple sheaths. The nitridation produces only a small volume change, which means that RBSN components do not need to be machined after fabrication and complex near net shapes can be produced in a single process stage.
Property | SSN GPS-SSN HPSN RBSN |
Density (g.cm-3) | 3.28 3.30 3.23 2.5 |
Young’s Modulus (GPa) | 285 320 315 189 |
Bend Strength (MPa) | 675 750 850 440 |
Fracture Toughness K1c (MPa.m0.5) | 6 7 8 2.5 |
Hardness (GPa) | 16 16 16 7.2 |
Thermal Expansion Coefficient (x 10-6/°C) | 3.2 3.2 3.2 3.2 |
Thermal Conductivity (W/m.K) | 25 30 30 14 |
Maximum Temperature (°C) for application Dielectric Constant Abrasive Wear resistance Parameter | 1650 1650 1650 1500 9 9 9 7.5 1110 1130 1120 360 |
Welcome to choose our Jinyu products, any further information, please E-mail to us. We will give you more details.
20 years Manufacturer SI3N4 Silicon Nitride Thermocouple Protection sheaths