Fostering the Aerospace Frontier with Advanced Ceramics

Aerospace applications often require materials with unique properties due to the extreme conditions they are exposed to. Kyocera Fineceramics Precision, a global leader in advanced technical ceramics, provides such materials. Here, we look at some of these advanced materials and see how they are helping drive innovations in the aerospace industry.

The aerospace industry has always been one that thrives at the frontiers. Next-generation air- and spacecraft, whether for atmospheric flight, low-earth orbit, or beyond, often require a unique combination of particular features. For example, they must be lightweight, compact, durable, and able to resist thermal shock.

Progress in this field is driven by innovative approaches and state-of-the-art designs, which fundamentally rely on the development of new materials with essential physical properties such as high mechanical strength, high fracture toughness, low density, and high thermal shock resistance.

One material category that stands out with its distinctive properties is advanced ceramics. Unlike metals or polymers, ceramics can resist heat variations and maintain dimensional stability at elevated temperatures. And where ceramics display a particular disadvantage, as in brittleness, reinforcements come into play, creating ceramic composites of high reliability and improved properties.

So, what are those advanced ceramics, and how do they fare in a rapidly growing and extremely demanding industry?

Figure 1. Fine ceramics are vital materials for aerospace propulsion system components due to their exquisite material properties.

Advanced ceramics uncovered

Aerospace has been a large playground for ceramics producers, especially fine ceramics. Non-oxides such as silicon carbide (SiC) and silicon nitride (Si₃N₄), and technical oxides like alumina (Al₂O₃), aluminium titanate (Al₂TiO₅), and zirconium oxide (ZrO₂), headline the technical ceramics arena. 

Providing a variety of 200+ ceramic materials, Kyocera has also included in its arsenal cutting-edge ceramic composites such as silicon infiltrated silicon carbide (SiSiC), a material that offers unmatched mechanical and thermal properties. One very interesting feature of SiSiC is that it is electrically conductive, contrary to almost all other ceramics, which are generally known for high electrical resistivity values. 

With such highly developed materials, Kyocera offers a range of processing capabilities that include effective manufacturing (such as milling, turning, and polishing), sintering, and coating. But what differentiates these materials from the rest? 

Below, Table 1 shows a comparison between ceramics and metals used in aerospace. Low density, high hardness, thermal conductivity, and elastic modulus are evident properties achieved by Kyocera’s fine ceramics. In addition to that, these ceramics display high thermal shock resistance, low coefficients of thermal expansion, high dimensional and chemical stability, and excellent corrosion resistance, properties that support their position in the aerospace industry.

In a nutshell, an enriched performance and long-term durability can be attained with advanced ceramics based on application-specific conditions.

Table 1. A comparison between ceramics and metals’ main properties

Material Property	Ceramics			Metals
	SiSiC	SSiC	Si3N4	Al 6061	Ni 718
Density (g/cm3) at 20°C	3.05	3.1	3.22	2.7	8.22
Hardness, Vickers at 20°C	2040	2550	1530	111	380
Thermal Conductivity (W/m·K) at 20°C	175	125	20	166	14.2
Elastic Modulus (GPa) at 20°C	380	395	290	70	200

Applications of advanced ceramics

The attractive properties of advanced ceramics lend themselves to a range of applications.

Propulsion systems, the components that constitute the rocket engine, require a high propulsion efficiency. This can be reached by reducing vehicle weight, minimising fuel consumption, and improving material durability.

Here is where a material like silicon carbide (SiC), with its excellent physical and high-temperature properties, including low density, corrosion resistance, low thermal expansion, and high thermal conductivity, can be a fitting material that maintains the components’ conditions against complex phenomena like deformation, creep, fatigue, heat transport, and corrosion.

StarCeram® S sintered silicon carbide (SSiC) from Kyocera, with its exceptional wear resistance, high strength, and high hardness complementing the properties mentioned above, is a great candidate for such an application.

Moreover, a reaction-bonded composite of silicon carbide particles in a matrix of surplus silicon, produced under the name of StarCeram® Si silicon infiltrated silicon carbide (SiSiC), is another option of Kyocera’s fine ceramics that can bring about outstanding performance. Of its numerous uses are bearing bushes, rotors, nozzles, seals, and wear protection parts.

As propulsion process temperatures may reach very high levels, the propulsion components’ performance could be highly affected. These include structural components, parts in engines and exhaust systems, and heat protection shields. SiSiC and SiC can easily guarantee high performance and long life, owing to their maximum service temperatures, in addition to their high corrosion and wear resistance properties.

Another application area for technical ceramics is the structural and frame parts for system integration. Optical benches, for example, require a certain level of rigidity, lightweight, mechanical vibration frequency, and thermal deformation. Ceramics’ damping ability, low density, shock resistance, and low thermal expansion give them the chance to be superior materials for such uses.

Further applications for Kyocera’s silicon carbide-based materials and other fine ceramics, like StarCeram® N silicon nitride (Si₃N₄), include electronics – as in sensors, capacitors, and resistors – and mechanical and structural parts – such as sliding rings, slide valves, cylinder linings, and welding rolls – that require thermal stability, high hardness, and rigidity.

Figure 2. SSiC and SiSiC materials can be used in nozzles of space rockets, with their excellent high-temperature properties.

What does the future hold for advanced ceramics?

The world of advanced ceramics continues to grow as ceramics and ceramic composites are constantly providing for and supporting different aerospace applications. Their exceptional properties remain a strong basis for their place in the materials race.

As modern and future innovations in aerospace will require greater properties, especially in terms of weight reduction, hardness, and thermal characteristics, technical ceramics and ceramic composites will most likely take the place of metals and glass-based materials, and more customisation and optimisation will be involved. This is where innovative companies like Kyocera, can play a significant role. 

Kyocera, thanks to its in-house powder preparation and unique material recipes, can provide provenly reliable and high-performance advanced ceramics from a range of over 200 materials. With aerospace opening up to new materials and new frontiers, Kyocera’s advanced ceramics will take centre stage as the materials for improved air- and spaceflight.

Visit the KYOCERA Fineceramics Precision supplier page for more information on their materials listed on Matmatch and to get in direct contact with them.