Single crystal casting of gas turbine blades using superior ceramic core

Kim, Eun‐Hee; Park, Hye Yeong; Lee, Cho-long; Park, Jong Bum; Yang, SeungCheol; Jung, Yeon‐Gil

doi:10.1016/j.jmrt.2020.01.029

Cited by 24 publications

(12 citation statements)

References 15 publications

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“…Ceramic core is withdrawn by applying chemical-etching method after casting completion. 14,15 Due to the complex geometry and in some cases low dimensional accuracy occasionally, the ceramic core is not removed completely. 13,16 Remain ceramic decreases the flow rate of cooling fluid or even block the cooling passage and prevent from sufficient blade cooling.…”

Section: Introductionmentioning

confidence: 99%

Nondestructive inspection of gas turbine blades by active thermography using different fluids

Mohammadian

Akbari

Farahani

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part B:

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Presence of defects in the gas turbine blades’ affects the blade performance and reduces the blade life. One of the common defects in the internal cooling passages of a gas turbine blade, is residual ceramic created in the blade production stage. This types of defects, can be beneficially detected by using active thermography. In this paper, nondestructive testing of internal cooling passages of a gas turbine blade is conducted by active thermography method using different types of excitations. Carbon dioxide (CO2), hot air, and water-vapor were selected as excitation sources. Inspection with water-vapor stimulations were performed at three different pressures flow rates. Results indicated that the IR thermography tests with water-vapor excitation, provide higher detectability compared to the other methods. However, internal passages were revealed by all of the pre-mentioned excitation methods. Residual ceramic in internal passages of the blade were clearly revealed by application of hot air and water-vapor. Results also indicated that application of the maximum pressure and flow rate, offer a better detectability and visibility. Some surface defects on the gas turbine blades were also been detected by application of water-vapor excitation.

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Section: Introductionmentioning

confidence: 99%

Nondestructive inspection of gas turbine blades by active thermography using different fluids

Mohammadian

Akbari

Farahani

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part B:

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“…The ceramic cores used for the fabrication of complex and precise products should exhibit a high dimension stability and high strength that can withstand the weight of molten metals at high temperatures. In addition, cores should possess excellent elution properties for their effective removal after casting 4–6 . Organic binders, also known as resins, have been extensively used for the fabrication of ceramic cores 7,8 .…”

Section: Introductionmentioning

confidence: 99%

“…In addition, cores should possess excellent elution properties for their effective removal after casting. [4][5][6] Organic binders, also known as resins, have been extensively used for the fabrication of ceramic cores. 7,8 Organic binders can main-tain the shape of ceramic green bodies before sintering or firing owing to their high viscosity at room temperature.…”

Section: Introductionmentioning

confidence: 99%

Enhancing fracture strength of ceramic core using sodium silicate as the binder

Park

Jung

Kim

et al. 2022

Int J Applied Ceramic Tech

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Ceramic cores used in the casting must exhibit high heat resistance because they come in direct contact with molten metals. Therefore, in this study, ceramic cores with high heat resistance and fracture strength were fabricated using sodium silicate as the binder instead of a commonly used organic binder. In addition, the prepared ceramic core was coated with Si and Si-Na precursors as the inorganic binder to improve the firing strength of the ceramic core. The thermal stability and firing strength of the sample were investigated. The results revealed that the firing strength of the ceramic core was significantly improved up to 15.2 MPa owing to the formation of a glass phase between the ceramic particles, which was formed by the reaction of sodium silicate and the inorganic binder precursor. In addition, the core was completely decomposed in an NaOH solution at a relatively low temperature of 60 • C, indicating the excellent elution properties of the sample. These results indicate that the method proposed in this study is suitable for the preparation of ceramic cores with high fracture strength and excellent elution behavior.

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“…Ceramic core materials are widely used for casting high‐temperature hollow parts, including directionally solidified and single‐crystal superalloys blade and vanes. They can form the complex inner cooling channels in hollow parts, which can improve the cooling efficiency in the application at high temperature 1‐3 . The key technology for hollow parts with high properties is the preparation of ceramic cores with excellent comprehensive properties.…”

Section: Introductionmentioning

confidence: 99%

Preparation, mechanical, and leaching properties of CaZrO₃ ceramic cores

Yang

et al. 2021

Int J Applied Ceramic Tech

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The CaZrO3 ceramic core materials with excellent mechanical and chemical properties were successfully prepared using single‐phase CaZrO3 powders. Effects of particle size ratio and sintering temperature on the mechanical and chemical properties of CaZrO3 ceramic core materials were researched. The chemical property was analyzed by leaching research of core materials in 10 wt% and 20 wt% HNO3 solution at the boiling point. Results showed that the suitable particle size ratio was important for the preparation of CaZrO3 ceramic core materials with excellent comprehensive properties. The addition of fine particles in ceramic core materials promoted the densification process owing to the framework formed by coarser particles and sintering neck formed by fine particles between coarse particles, which was beneficial for further improving their bending strength. When the content of particles with 200 mesh size was 80wt%, the highest bending strength was obtained, 54.38 ± 5.28 MPa. The porosity was 17.45% and the volume density was 3.86 g/cm3. The increasing sintering temperature increased the densification of CaZrO3 ceramic core materials by offering the sintering driving force, further leading to the improvement of bending strength. When the temperature was 1650℃, at the 20% content of particles with 200 mesh size, the highest bending strength of CaZrO3 cores reached 51.01 ± 5.18 MPa. Meanwhile, the porosity was 18.65% and the volume density was 3.83 g/cm3. Additionally, the CaZrO3 samples could be effectively leached in 10 wt% HNO3 solution. Therefore, CaZrO3 materials with good mechanical and leaching properties were believed to be a suitable candidate for ceramic core materials in the investment casting of alloys with high melting point.

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Single crystal casting of gas turbine blades using superior ceramic core

Cited by 24 publications

References 15 publications

Nondestructive inspection of gas turbine blades by active thermography using different fluids

Nondestructive inspection of gas turbine blades by active thermography using different fluids

Enhancing fracture strength of ceramic core using sodium silicate as the binder

Preparation, mechanical, and leaching properties of CaZrO₃ ceramic cores

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Single crystal casting of gas turbine blades using superior ceramic core

Cited by 24 publications

References 15 publications

Nondestructive inspection of gas turbine blades by active thermography using different fluids

Nondestructive inspection of gas turbine blades by active thermography using different fluids

Enhancing fracture strength of ceramic core using sodium silicate as the binder

Preparation, mechanical, and leaching properties of CaZrO3 ceramic cores

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Product

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Preparation, mechanical, and leaching properties of CaZrO₃ ceramic cores