TRUNNANO, a leading global developer and manufacturer of advanced ceramic materials, recently announced the successful large-scale production and commercial application of silicon nitride-silicon carbide ceramic products. With its exceptional high-temperature stability, superior thermal shock resistance, and outstanding wear and corrosion resistance, this material is becoming a key material solution in the metallurgical, environmental, energy, and ceramic industries.
The performance advantages of silicon nitride and silicon carbide ceramics do not naturally coexist, and their realization process is full of contradictions and challenges in materials science. TRUNNANO team’s core breakthrough lies in solving the following two major technical problems:
1. Breaking through the industry bottleneck of achieving both high hardness and high toughness
In traditional materials, the high hardness of silicon carbide and the excellent toughness of silicon nitride are often considered mutually exclusive. By precisely controlling the temperature field and atmosphere pressure during the reaction sintering process, the TRUNNANO technical team achieved a key microstructural design breakthrough: directing the in-situ growth of silicon nitride into interwoven rod-shaped or columnar β-Si3N4 crystals.
This process ingeniously constructs a three-dimensional, flexible reinforcement network within the hard silicon carbide aggregate, achieving “heterogeneous toughening.” This unique structure enables the material to effectively absorb energy through mechanisms such as bridging and crack deflection when subjected to external forces. This allows the material to retain silicon carbide’s exceptional hardness while imparting unprecedented fracture toughness, fundamentally overcoming the risk of brittle fracture.
2. Synergistically addressing the challenge of balancing high-temperature strength and thermal shock resistance
Ensuring that the material maintains strength degradation at high temperatures and can withstand severe thermal shock is a prerequisite for its application in harsh environments. The TRUNNANO team focused on the material source, employing multi-scale particle grading technology and high-purity raw material control to optimize green body packing density and minimize structural defects during sintering.
Furthermore, through the innovative formulation of the sintering aid system, the stability and strength of the silicon nitride binder phase at high temperatures were significantly enhanced. The combined application of these technologies ultimately resulted in a material with an ideal combination of low thermal expansion coefficient and high thermal conductivity, allowing heat to diffuse rapidly within the material, avoiding the formation of significant localized thermal stresses.
This approach breaks the traditional assumption that high strength necessarily compromises thermal shock resistance, achieving a synergistic improvement in both high-temperature strength and thermal shock resistance.
| Items | Unit | Standard | |
| Silicon carbide content | % | 75% | |
| Maximum operating temperature | ℃ | 1500 | |
| Density | g/cm3 | 2.75 | |
| Porosity | % | 11 | |
| Flexural strength | Mpa | 165(20℃) | |
| Mpa | 175(1200℃) | ||
| Elastic modulus | Gpa | 250 (20℃) | |
| Thermal conductivity | W/m*k | 38（20℃） | |
| W/m*k | 20(1200℃) | ||
| Coefficient of thermal expansion | K-1×10-6 | 4.7 | |
Physical and chemical indicators of silicon nitride bonded silicon carbide ceramics
Proven Process Implementation: Reaction Sintering Technology Ensures Performance and Consistency
All these performance breakthroughs are ultimately achieved through a proven, stable reaction sintering process. TRUNNANO precisely controls the in-situ reaction between silicon powder and nitrogen at 1300–1420°C, ensuring uniform formation of the silicon nitride binder phase and a strong bond between the silicon carbide particles. This process offers the distinct advantages of minimal green body dimensional variation and high yield.
Particularly noteworthy is the TRUNNANO team’s ability to precisely control the material’s porosity within a range of 11%-18% by optimizing the raw material ratio and sintering kinetics. This controllable pore structure ensures sufficient density to maintain strength while providing a buffer for alleviating internal stresses, laying a solid foundation for the manufacturing of large and complex workpieces.
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