Advancements In Aerospace: Ceramic Materials In Space Applications
The aerospace industry is one of the largest adopters of additive manufacturing (AM). 3D printing enables manufacturers to create lighter, more durable components that withstand extreme conditions for a fraction of the cost of traditional production techniques. In this area, ceramic materials are changing the game.
Why Ceramic Materials in Aerospace?
Ceramics are having a moment in additive manufacturing for space. Here's why:
Excellent Thermal Resistance
Ceramics are capable of handling extreme temperature fluctuations, which is critical in components like heat shields. Space Shuttle tiles, for example, must withstand the high temperatures of reentry into Earth's atmosphere—up to 3,871 degrees Celsius (7,000 degrees Fahrenheit).
High Strength-to-Weight Ratio
Ceramics are strong yet lightweight. Manufacturers can increase payloads without compromising fuel efficiency.
Extreme Durability
Objects in space are subject to wear and tear. Ceramics hold up against micrometeoroid impacts and cosmic radiation.
Electrical Insulation
Ceramic is an insulator, which is uniquely beneficial for components expected to perform in space—a harsh electromagnetic environment. Manufacturers can use ceramics to protect spacecraft electronics without adding excessive weight.
Chemical Stability
Aerospace components need to remain effective over potentially long durations. During this time, they are exposed to extreme and potentially damaging forces like atomic oxygen and UV radiation. Ceramics are extremely stable even in an environment as harsh as space.
3D Printed Aerospace Components
3D printing allows manufacturers to produce customisable parts for aerospace customers without using moulds. Even complex shapes and designs not possible with traditional manufacturing can be 3D printed at comparatively low costs.
Use cases include:
- Thermal protection systems that safeguard vehicles against reentry heat
- Propulsion components like fuel nozzles
- Electrical insulation
- Lighter-weight structural elements that improve fuel efficiency
Single-Step and Multi-Step 3D Printing Processes
Ceramics can be 3D printed using a single-step or multi-step process.
Using the single-step method, the ceramic material is shaped and hardened—or sintered—in one step. It's generally the faster and more resource-efficient approach.
Either direct laser sintering (dLS) or directed energy deposition (DED) can be used:
- dLS fuses ceramic powder layer by layer until the desired shape is formed.
- In DED, ceramic material is melted and then deposited onto a surface. This technique is best suited to larger components.
During the multi-step process, the part is formed as a soft, unfired shape called a green body. This is then debound and sintered. Although it takes longer, multi-step 3D printing gives designers and engineers more control over the shape and material properties.
Looking Ahead: Challenges and Opportunities in Ceramic 3D Printing for Aerospace
Ceramics for 3D-printed aerospace components are already enabling manufacturers to produce robust, lower-cost custom components. However, there's room for improvement.
One major challenge is ceramic's tendency to shrink after sintering. This property makes accurately predicting the finished size and shape of the part more difficult. Parts might not fit together as expected, or they might not be as strong as needed to withstand tough conditions.
In addition, achieving a smooth surface on intricate ceramic parts—particularly those with complex core-shell moulds—is difficult with current technology. Small imperfections on the surface of ceramic parts affect its performance and can lead to unpredictable behaviour. Although additional processing can fix these issues, the added step adds to both the time and cost of production.
With challenges come opportunities to innovate. In the future, we expect to see improvements made to ceramic material formulations. Additives might be incorporated to mitigate the effects of uncontrolled shrinking and surface imperfections.
Image via https://unsplash.com/photos/four-brown-planters-Ljz_Wmk7t7g
