Development of Cost-Effective Low-Permeability Ceramic and Refractory Components for Aluminum Melting and Casting
- Pyrotek
- ORNL
The primary goal of this project was to develop and validate new classes of cost-effective low-permeability ceramic and refractory components for handling molten aluminum in both melting and casting environments. Three approaches were employed with partial to full success to achieve this goal: (1) Develop materials and methods for sealing surface porosity in thermal-shock-resistant ceramic refractories; (2) Develop new ceramic coatings for extreme service in molten aluminum operations, with particular emphasis on coatings based on highly stable oxide phases; and (3) Develop new monolithic refractories designed for lower-permeability applications using controlled porosity gradients and particle size distributions. The results of the research work and the field tests performed utilizing these three approaches are listed below: (1) It was demonstrated that high-density IR heating could be a tool for altering and sealing the surface porosity of fused silica. However, the process was not very cost-effective. (2) A low-cost glaze composition having a coefficient of thermal expansion (CTE) similar to that of a DFS tube was identified and was successfully tested for its integrity and adherence to DFS. Although the glaze acted as a barrier between the molten aluminum and the DFS, persistent porosity and crazing within the glaze affected its performance during the reactivity tests, thus acting as an obstacle in scaling up production of this glaze. (3) Pyrotek's XL glaze showed great success in improving the life of the DFS tubes. Pyrotek has reported an increasing market demand for the XL-coated DFS tubes, which exhibit useful lifetimes three times better than those of uncoated tubes. (4) A computer model to optimize particle size distribution for reduced permeability was developed and successfully applied to casting formulations. Silica riser tubes produced using these new formulations have been tested in a commercial aluminum casting facility and have been reported to increase the life of the DFS tubes by 700%. (5) If all the DFS riser tubes used in LPD casting of aluminum automotive components are replaced with the better, longer-lasting castable riser tubes, the potential national energy savings is estimated to be 206 billion Btu/year.
- Research Organization:
- Pyrotek, Inc.
- Sponsoring Organization:
- USDOE Office of Energy Efficiency and Renewable Energy (EERE)
- DOE Contract Number:
- FC36-02ID14244
- OSTI ID:
- 878541
- Report Number(s):
- ORNL/TM-2005/266; TRN: US200716%%81
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ALUMINIUM
CASTING
CERAMICS
COATINGS
COMPUTERS
FIELD TESTS
GLAZES
HEATING
MARKET
MELTING
OXIDES
PARTICLE SIZE
PERMEABILITY
POROSITY
REFRACTORIES
SILICA
THERMAL EXPANSION
refractory
aluminum
glaze
pressure die casting
high-density infrared
wettability
premiability
particle-size distribution