New Technology
Freeze Casting
Ceramic Components
Morgan Advanced Ceramics’ freeze cast process offers for the first time, truly durable cast ceramic components, capable of use in a wide range of high wear applications.
The process of freeze casting is not a new concept, however the ability to produce repeatable, high quality product, making it viable as a commercial offering is unique to Morgan Crucible. The process involves casting a ceramic mixed with a ‘sol’ before cryogenically freezing it. The product is then allowed to defrost and once dry is fired.
As well as providing a material that can substitute metals such as invar in composite tooling for example, freeze cast ceramic has offered ceramic solutions for a number of areas that would have had no other feasible alternative.
The thermal properties of ceramic for example are well utilized in smaller componentry and are now with freeze casting are finding uses within far larger products. We have produced freeze cast ceramic product for applications requiring standard ceramic capabilities such as thermal shock resistance, continuous high temperature use (1500 deg. C +) and for thermal insulation.
The early applications tended to come from the Aerospace industry, but we now distribute to a range of industrial and high tech industries.
Freeze casting can be used to produce the smallest of ceramic components up to our current capacity of 2m x 1m product, which limited only by the size of the freezer.
Example applications:
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Composite forming tools
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Large geometry thermal applications (insulation or thermal shock)
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Large refractory ceramics
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Specialist calibration blocks
Benefits of freeze cast ceramics:
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Large and complex geometries available:
Products can be supplied in sizes of greater than 2m x 1.5m. For still larger requirements, flush-fitting sectioned tools can be produced. Complex working surface geometries can be achieved without need for secondary processing.
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Precision: Because components are made by the Freeze Casting process are near net shape after firing, the system offers excellent precision, particularly for components which are to be used in conjunction with other parts or as forms. This removes the need for extensive machining after casting. Example tolerancing over 1.5m x 1m, complex geometry mould is ±0.2mm in all aspects.
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Freeze cast ceramics have excellent thermal stability:
Because it is a fully fired ceramic (fired to 1200°C) the components remain flat and distortion free with extended use. Unlike many other ceramic materials based upon castable alumina, the ceramic used here has graded properties, which makes it an ideal candidate material for super plastic forming tooling
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Low mass: Freeze cast ceramic is 40% the density of high temperature steels.
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Hardness: The working surface of the ceramic is a composite of Chrome Oxide and Aluminium Oxide and hardness can be developed as high as 40 on the Rockwell C Scale
Materials
A range of materials have been developed to suit a variety if applications:
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Alumina – for extremely complex geometries requiring a tough working surface
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Fused Silica – Almost zero thermal expansion.
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Alumina-silicates – for a variety of thermal wear or thermal shock applications
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Silicon Nitride (in
development)
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