A prototype knowledge-based system for material selection of ceramic matrix composites of automotive engine components

Ceramic Matrix Composites (CMC) have a wide interest for high temperature applications. The materials can be modified by the selection of the matrix precursor as well as of the reinforcing materials. C/C-composites can be easily modified by post-treatments with silicon in order to acquire different tribological properties from good sliding behaviour up to braking systems only depending on the manufacturing technique of these materials. It will be demonstrated during the presentation that the manufacturing depends on one hand side on the material which has to be manufactured and on the other side on the structural component and the number of parts which are required. Furthermore, it will also be shown, that silicon treatments can be performed up to a full conversion of C/C materials creating a new family of monolithic ceramic materials. Within the presentation detailed information will be given on possible processing routes as well as the resulting physical and mechanical properties of the materials.

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Evaluation of Ceramic Rotor Strength by Cold and Hot Spin Tests

Volume 2: Aircraft Engine; Marine; Microturbines and Small Turbomachinery ◽

10.1115/94-gt-460 ◽

1994 ◽

Cited By ~ 1

Author(s):

Makoto Watanabe ◽

Hiroshi Ogita

Keyword(s):

Gas Turbine ◽

Gas Turbines ◽

High Speed ◽

Bending Strength ◽

Ceramic Matrix Composites ◽

Ceramic Matrix ◽

High Heat ◽

Turbine Rotor ◽

Matrix Composites ◽

Automotive Engine

Presently in Japan 100 kW ceramic gas turbines (CGT) for automobiles are under development, parts of which include a turbine rotor, scrolls, a combustor, and other parts made of ceramics and ceramic matrix composites. The rotor is designed to rotate at 110,000 rpm, equal to the maximum stress of 300 MPa and to be exposed to temperatures up to 1350°C. Initially, the strength of ceramic rotors was evaluated by a burst test using a cold spin tester. The burst picture was observed and compared with the 4pt bending strength of the ceramic test specimens. Next, the strength of the rotors was tested by a hot spin test and the burst result of the rotor was evaluated. A high speed camera was used to observe the rotor at the instant of burst under a high temperature condition. Applying the result of the cold and hot spin tests, ceramics for turbine rotor were selected and the shape of the rotor was designed as a practical automotive engine began in 1990 as a project of the Petroleum Energy Center with financial support from the Agency of Natural Resources and Energy, the Ministry of International Trade and Industry. In order to obtain a 40% or higher thermal efficiency, the automotive gas turbine requires the use of a turbine rotor, combustor, shroud and other engine parts that can withstand high temperatures of 1200°C to 1500°C. In addition, since their resistance to thermal stress and impact are primary considerations, it is necessary to develop high heat-resistant materials (ceramic type materials). Fig. 1 shows a sectional model of the automotive ceramic gas turbine now under development. Under this project, a monolithic ceramic rotor was first evaluated as a turbine rotor. Ceramic matrix composites were then studied.

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Thermal Gradient Cyclic Behavior of a Thermal/Environmental Barrier Coating System on SiC/SiC Ceramic Matrix Composites

Volume 4: Turbo Expo 2002, Parts A and B ◽

10.1115/gt2002-30632 ◽

2002 ◽

Cited By ~ 4

Author(s):

Dongming Zhu ◽

Kang N. Lee ◽

Robert A. Miller

Keyword(s):

Heat Flux ◽

Ceramic Matrix Composites ◽

Ceramic Matrix ◽

Cyclic Behavior ◽

Thermal Barrier ◽

Matrix Composites ◽

Environmental Barrier Coatings ◽

Environmental Barrier ◽

Sic Ceramic ◽

Engine Components

Thermal barrier and environmental barrier coatings (TBCs and EBCs) will play a crucial role in future advanced gas turbine engines because of their ability to significantly extend the temperature capability of the ceramic matrix composite (CMC) engine components in harsh combustion environments. In order to develop high performance, robust coating systems for effective thermal and environmental protections of the engine components, appropriate test approaches for evaluating the critical coating properties must be established. In this paper, a laser high-heat-flux, thermal gradient approach for testing the coatings will be described. Thermal cyclic behavior of plasma-sprayed coating systems, consisting of ZrO2-8wt%Y2O3 thermal barrier and NASA Enabling Propulsion Materials (EPM) Program developed mullite+BSAS/Si type environmental barrier coatings on SiC/SiC ceramic matrix composites, was investigated under thermal gradients using the laser heat-flux rig in conjunction with the furnace thermal cyclic tests in water-vapor environments. The coating sintering and interface damage were assessed by monitoring the real-time thermal conductivity changes during the laser heat-flux tests and by examining the microstructural changes after the tests. The coating failure mechanisms are discussed based on the cyclic test results and are correlated to the sintering, creep, and thermal stress behavior under simulated engine temperature and heat flux conditions.

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