Abstract of the Offer
Lucideon, a UK materials development SME, is developing ceramic matrix composites (CMCs) for high temperature survivability for applications such as reusable thermal protection systems.
CMCs allow for high operating temperatures and mechanical loading in harsh environments. Lucideon works with oxide and non-oxide CMCs through matrix formulation, forming, densification, sintering, modelling, performance analysis and evaluation.
Lucideon seeks partnerships for technology development.
Description
CMCs address the brittleness issue that monolithic ceramics exhibit by incorporating fibres into the matrix. Their fibre pull-out mechanism overcomes the failure that monolithic ceramics experience under stress. Below are the different types of CMCs:
UHTCMCs
Fibre – Carbon or ceramic fibre
Matrix – Zirconium/Hafnium Diboride/Carbide
Operating temperature - 2000°C+
SiC/SiC CMCs
Fibre – Silicon Carbide
Matrix – Silicon Cabride
Operating temperature - 1600°C
Ox/Ox CMCs
Fibre – Oxide (Alumina)
Matrix – Oxide (Alumina)
Operating temperature - 1200°C
Geoceramic MIDAR® Composites
Fibre – Carbon, Oxide, or mineral fibre
Matrix – MIDAR® technology
Operating temperature – up to 1100°C
Curing temperature <100°C
The manufacturing process is below:
1. Material Selection
CMC materials offer benefits in performance, efficiency and sustainability including:
- Excellent strength:weight ratio at extreme temperatures
- High temperature flux environment resistance
- Non-brittle behaviour in comparison to monolithic ceramics
- Tailorable properties due to composite structure
- Environmental resistance - selecting the right material and processing method is critical to meeting product requirements.
2. Matrix Material Preparation
Materials must display a very particular set of properties to be suitable for matrix impregnation. Correct viscosity, particle size distribution, and rheology characteristics are necessary to achieve uniform distribution throughout the end-product to ease processing and maximise performance.
3. Fibre Lay-up and Impregnation
Fibre provides strength and stiffness to the matrix material, while impregnation enables support, bonds, and protection to the fibre. Fibre orientation and location, combined with resin systems alter the properties of a matrix.
4. Heat Treatments
Once an impregnated fibre architecture is created, various heat treatments are deployed for further processing, consolidating the part and burning off binders and additives before final densification occurs.
5. Densification
Densification is the process of reducing the porosity of a composite, with the desired goal of making the final product more compact. Densification is achieved by filling pores with additional material or by compressing existing material using pressing or other technologies.
Post production, for example, joining and machining, is required for the desired geometry and surface finish, and the testing of the material is completed for validation.
Advantages and Innovations
Developments in the aerospace, space, defence and nuclear sectors are leading the demand for higher performing materials than those that are currently commercially availble. There is a need for materials to operate at higher temperatures and exhibit similar strength-to-weight properties, and CMCs is a solution.
Below are two example applications:
- Propulsion systems that can operate at higher temperatures within the combustion chamber are more efficient and ultimately burn less fuel. Currently, super alloys are used however, thermal barrier coatings and cooling veins are implemented to provide an incremental change in performance. CMCs (SiC/SiC) can operate up to 1600°C providing a step change in performance. In addition, their strength-to-weight ratio is higher, and, therefore, is a lighter alternative too. Other CMCs, such as Ox/Ox can be used as exhaust mixer components not only to withstand the higher temperatures but also because of its oxidation resistance
- Current thermal protection systems are replaceable. The material wastage and manufacturing costs and, therefore, expensive and unsustainable. Furthermore, the demand for hypersonic reusable vehicles is increasing and current materials will not withstand the temperatures to which it is exposed. UHTCMCs can withstand temperatures of 2000°C+ with good chemical stability, ideal for reusable thermal protection systems and leading edges for hypersonic vehicles
Currently, these materials can be costly to manufacture, however, Lucideon works in process optimisation and, as these become commercially available, the price is expected to drop.
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