Structural ceramics continue to be intensely popular. As demand continues to grow for materials to be stronger, more durable and lighter, manufacturers must look for new, innovative processes to produce the next generation of ceramics. Innovnano is one such manufacturer whose novel emulsion detonation synthesis (EDS) method of ceramic production allows them to produce a new form of yttria-stabilised zirconia which has a remarkably higher toughness.
AZoM spoke to André de Albuquerque, CEO of Innovnano, about recent developments in the ceramics industry, the EDS process and Innovnano's unique approach to the ceramics industry.
Which types of structural ceramics are currently popular?
Structural ceramics have been enjoying strong and consistent growth over the past years, and demand is expected to continue increasing. This increased demand for structural ceramics results both from growth in many different applications as well as the fact that the ceramics market share has been increasing for several products; as they have been replacing plastics and metals in high-performance applications such as medical and dental.
In terms of type of materials, Zirconium Oxide, Aluminium oxide (Al2O3), silicon carbide (SiC), aluminium and silicon nitrides (AlN and Si3N4) and aluminium-zirconium oxide composites (commonly known as ATZ (alumina toughened zirconia) and ZTA (zirconia toughened alumina)) are among the most commonly used.
These ceramics are being used in all sorts of applications from automotive and aeronautics, to use by the defense industry. Ceramics also are used frequntly in industry as components in refractories or as abrasives.
In addition to this, scientific literarure is showing that materials such as ceramic metal composites (cermets) are starting to present strong solutions for structural ceramics applications, which means that in the near future they will start to have their own market position.
Ceramics are a vital material for the aerospace industry - where demand for tough materials is high. shutterstock.com | ID1974
How do Innovnano’s 2YSZ ceramics improve on 3YSZ ceramics?
In general, a lower amount of yttria in the composite means a greater susceptibility to the induction of tetragonal-monoclinic transformation and thus an increase in fracture toughness. However, usually, a reduction of yttria results in other properties being affected such as the flexure strength and ageing resistance.
Innovnano 2YSZ offers the possibility of having the benefits of reduction in Yttria (namely a significant increase in fracture toughness) without compromising other properties of a regular 3YSZ. As such, 2Y offers a similar flexural strength as the benchmark 3Y with 2.5 times the toughness and 50% more resistance to cyclic fatigue.
What are the structural and molecular differences between 2YSZ and 3YSZ? What properties do the yttria and zirconia provide?
It is well known that the role of Yttria in YSZ is as stabilizer to maintain the tetragonal phase, which is responsible for the high mechanical performance. Therefore, from a structural point of view, both 3 and 2YSZ are tetragonal Zirconias.
The key aspect is that Innovnano unique synthesis process presents the ability to stabilize zirconia in tetragonal phase using a reduced amount of yttria, producing the outstanding fracture toughness level.
What other inorganic additives are present in 2YSZ? What roles do they play?
Innovnano 2YSZ powder ceramics are identical to 3YSZ powders except for the yttria content.
How do Innovnano produce 2YSZ?
We use an Innovnano patented synthesis process based on the detonation of water-in-oil emulsions, called Emulsion Detonation Synthesis (EDS).
Emulsion Detonation Synthesis is our unique manufacturing synthesis process and it sets us apart from other suppliers. Originating from work at our parent company - CUF - EDS offers a revolutionary manufacturing solution for the high volume, high quality production of nanostructured powders.
Categorised as a gaseous-phase synthesis technique, the fully automated EDS process improves the industrial production of high quality ceramic powders.
Diagram illustrating the EDS process
Why does Emulsion Detonation Synthesis produce a superior ceramic?
EDS combines high temperature and extreme pressure with a microsecond scale quenching rate. This creates a nanostructured ceramic. It also retains some phases in a metastable state at temperature and atmospheric pressure, which are characteristic of the phase diagrams at high temperatures and/or pressures.
The combination of these two aspects - nanostructure and quenching rate - is the key to stabilizing a tetragonal phase with a lower yttria content like our 2YSZ.
This is not usually achievable using other conventional processing routes. In addition, this process has the ability to prepare other disruptive materials, such as ceramic metal composites (cermets), or even produce tailor-made materials based on metastable phases like cubic zirconium tungstate that can also be used in zero expansion structural ceramics.
What industries will 2YSZ ceramics benefit most? Was it designed with a certain customer in mind?
Primarily, the structural ceramics industry that today uses 3YSZ can immediately benefit from the introduction of a flaw tolerant ceramic. This is due to the high toughness values that 2YSZ presents. Better results from the weibull distribution also reflect that the probability of failure to occur with this material is lower than what is typical with 3Y.
2Y can advantageously replace 3Y in the production of ceramic parts for most of its current applications. The list comprises pump linings, valve components, nozzles, cutting tools, welding pins, dies and tooling, roller bearings, implants and extruders among others, covering a breath of industries that includes foundries, industrial machinery and equipment, defense, chemicals and pharmaceuticals, to name a few.
Under a different perspective, 2Y also enables manufacturers to expand their actual markets by taking advantage of the high toughness and exceptional resistance to cyclic fatigue that it presents, using it for the production of ceramic parts with shock absorption and dynamic demand requirements that often can only be met with metal alloys.
Ceramics are heavily used in industry. shutterstock.com | T photography
Are there any ceramics similar to 2YSZ on the market? How do they compare?
Some material groups have high flexural properties (ZrO2+Al2O3) but with lack of toughness, conversely there are others with high toughness (ZrO2 stabilized with Ca/Mg) but with very low strength.
Innovnano 2YSZ combines these two mechanical properties, high flexure strength and fracture toughness, making it a unique product available to the market.
Do Innovnano provide assistance in using 2YSZ in novel applications?
Yes, it is part of our approach to partner with our customers in the search for the best solution for their needs. Under this context, our R&D team is prepared and used to interacting with customers and potential customers to understand the customer needs and to identify how to meet them.
Where can our readers find out more about 2YSZ and Innovnano?
Our team can be contacted via the company website, where additional product information is also available. Furthermore, we participate in several industry events throughout the year and often deliver technical presentations.
For example, we will have two presentations (or past tense, depending on the publishing date) at the European Ceramic Society conference and exhibition that will take place in July in Budapest.
About André de Albuquerque
André de Albuquerque is Chief Executive Officer at Innovnano, a dedicated manufacturer of structural zirconia ceramics. He also sits on the Board of Directors for Innovnano’s parent company CUF, a renowned company within the European chemical industry landscape.
Previous to Innovnano, André held various positions in industries such as ship repair, civil explosives and printed electronics following a degree in management and business administration from the Portuguese catholic university and postgraduate qualifications from the same university and AESE Business School. Andre has also been President of the Portuguese chemical industry association, as well as a vice president of the largest industrial confederation in Portugal.
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