Key Takeaways & Executive Findings
- •• 3D printing enables fabrication of complex ceramic cores without molds, significantly shortening production cycles. • Addition of 5% polysilazane optimizes flexural strength (31.5 MPa at 25°C, 13.1 MPa at 1500°C) and porosity (36.7%). • Polysilazane content regulates ceramic core performance; excessive amounts degrade mechanical properties. • This work provides a pathway for high-performance ceramic cores for investment casting of hollow turbine blades.
Abstract
The performance of an aero-engine is closely related to the cooling ability of the hollow turbine blades. Ceramic core is an important component in the production of hollow turbine blades with a complex structure. As the pace of updating and iteration in turbine blade design continues to accelerate, the internal cavity structures of turbine blades have become increasingly complex. Traditional hot injection process is difficult to meet the production requirements of ceramic cores with complex structures. 3D printing technology can manufacture ceramic cores without the need for moulds, significantly shortening the production cycle and providing a new technology for the production of ceramic cores with complex structures. To meet the technical requirements of the investment casting process, ceramic cores must possess adequate mechanical strength and appropriate porosity. In this work, the ceramic slurry with polysilazane (PSZ) precursor was successfully prepared, and the Al2O3-based ceramic cores with high performance were fabricated using 3D printing technology. The regulation mechanism of polysilazane on the performance of ceramic cores was investigated. The results show that with the increase of PSZ content, the flexural strength of ceramic cores firstly increases and then decreases. When the content of PSZ is 5%, the flexural strength at 25 °C and 1,500 °C are 31.5 MPa and 13.1 MPa, respectively, and the porosity is 36.7%. This work is expected to advance the research and practical application of high-performance ceramic cores fabricated via 3D printing.
1. Introduction
The hollow turbine blade designed with a complex internal structure provides a hollow cooling path [1]. This improves the temperature bearing capacity of turbine blades and can successfully fabricate the aero-engine with a high thrust-to-weight ratio. Ceramic cores are widely used to form complex inner cavity structures of aero-engine turbines [2], which is critical to the yield rate and quality of hollow blades [3]. Traditional processes for preparing ceramic cores are hot pressing, injection molding, and gelcasting, which often require expensive molds and are limited in producing complex geometries.
As the pace of updating and iteration in turbine blade design continues to accelerate, the internal cavity structures of turbine blades have become increasingly complex. Traditional hot injection process is difficult to meet the production requirements of ceramic cores with complex structures. 3D printing technology can manufacture ceramic cores without the need for moulds, significantly shortening the production cycle and providing a new technology for the production of ceramic cores with complex structures. To meet the technical requirements of the investment casting process, ceramic cores must possess adequate mechanical strength and appropriate porosity.
In this work, alumina ceramic slurry with polysilazane precursor was prepared, and Al2O3-based ceramic core was successfully prepared using 3D printing technology. The influence of polysilazane content on the properties of ceramic slurry and the resulting ceramic core was investigated, and the underlying regulation mechanism of polysilazane on the properties of ceramic core was analyzed.
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Sheng-qi Liu, Rui-long Yu, Wen-jun Dong, Qiao-lei Li, Ang Li, Wei Liu, Xi-he Liu, Xin-yan Yue, Jing-jing Liang, Jin-guo Li (2025). Effect of polysilazane on microstructure and properties of Al2O3-based ceramic core for 3D printing. China Foundry. https://doi.org/10.1007/s41230-025-5003-3
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Frequently Asked Questions
What is the role of polysilazane in 3D-printed ceramic cores?
Polysilazane acts as a precursor that improves the mechanical strength and porosity of Al2O3-based ceramic cores. Optimal addition (5%) yields flexural strengths of 31.5 MPa at 25°C and 13.1 MPa at 1500°C, with a porosity of 36.7%.
How does 3D printing benefit ceramic core production?
3D printing eliminates the need for molds, enabling rapid fabrication of complex internal cavity structures, significantly shortening production cycles compared to traditional hot injection molding.
What are the key properties required for ceramic cores in investment casting?
Ceramic cores must have adequate mechanical strength to withstand casting stresses and appropriate porosity to facilitate easy removal after casting, ensuring dimensional accuracy of hollow turbine blades.
What is the optimal polysilazane content for ceramic cores?
The optimal content is 5% polysilazane, which provides the best balance of flexural strength and porosity. Higher or lower contents result in reduced mechanical performance.
What is the significance of this research for aero-engine manufacturing?
This research advances the production of high-performance ceramic cores via 3D printing, enabling the fabrication of complex hollow turbine blades with improved cooling efficiency, thereby enhancing aero-engine performance and thrust-to-weight ratio.
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