Ceramics (Sialon powder)

SiAlON ceramic powder is a solid solution material composed of silicon, aluminum, oxygen, and nitrogen elements. It has high hardness, high-temperature oxidation resistance, and low thermal expansion coefficient, and is widely used in industrial wear-resistant parts, light conversion materials, and bioceramics. Here is a summary of its key information:
1. Basic characteristics and classification
Chemical composition: The general formula is Si ₆₋ₓ Al ₓ O ₓ N ₈₋ₓ (0 ≤ x ≤ 4.2), which forms an electrically neutral solid solution by replacing silicon and nitrogen atoms in silicon nitride with aluminum and oxygen atoms.
Crystal structure: divided into α – Theron (with poor performance) and β – Theron (with excellent performance), the latter is based on β – Si ∝ N ₄, hexagonal crystal system, and the lattice constant varies with the amount of solid solution.
Performance advantages: Vickers hardness reaches 16GPa, bending strength at 1300 ℃ is 700MPa, and high-temperature strength is maintained at 1400 ℃.
2. Powder preparation method
Direct synthesis method: Using Si ∝ N ₄, Al ₂ O ∝, AlN and other raw materials, high-temperature synthesis is carried out according to the phase diagram ratio, but the raw material cost and energy consumption are high.
Self propagating high-temperature synthesis (SHS) method: mixing Si powder, Si ∝ N ₄, etc., igniting the reaction in a nitrogen atmosphere to rapidly generate powder, which has been used for honeycomb ceramic exhaust treatment.
Improved process: The patented method using coal gangue as raw material can reduce costs, shorten reaction cycles, and achieve a Sailon content of 90wt%.
3. Application Fields
Industrial components: metal smelting diversion rings, nozzles (with a lifespan of over 814 hours), thermocouple protective sleeves, etc.
Light conversion material: Rare earth doped for white LED, optimized synthesis temperature to 1400-1500 ℃ through gas-phase reduction nitridation method.
Bioceramics: Artificial joints, etc., with both biocompatibility and mechanical strength.