STA Sialon silicon nitride riser tube or Stalk tube for Aluminum Low Pressure Casting
STA Sialon silicon nitride riser tube Stalk is made by unique high density Silicon Nitride possessing superior durability. STA Ceramic can meet various requirements of users on design and application assured by abundant supply record.
STA sialon Ceramics is used as basic material.
(1) High strength: High bending strength of 780MPa without deterioration up to 800deg. C.
(2) High density: High dense material with porous ratio of less than 0.3% (3) High toughness: The highest fracture toughness(KIC) of 7.2MPa x m1/2 among ceramic materials (4) High performance: Almost no erosion in molten aluminum and low wettability
STA Ceramics provide various dimension (Manufacturable dimension)
Silicon nitride ceramic material with high thermal stability ,antioxidant ability,and product size excellent performance. 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.Key PropertiesApplications exploit the following properties of silicon nitridelow densityhigh temperature strengthsuperior thermal shock resistanceexcellent wear resistancegood fracture toughnessmechanical fatigue and creep resistanceExcellent non-wetting property with good oxidation resistance
SSN GPS-SSN HPSN RBSN
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
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 applicationDielectric ConstantAbrasive Wear resistance Parameter