Zirkonoxidkeramik are demanding in today’s world. Zirconia in its natural form or Baddeleyit (ZrO2) is generally the source to obtain ZrO2. To use Zirconia in distinct application, it is crucial to learn about its property of fracture toughness. The article gives an overview on fracture toughness of Zirconia ceramics.
Was ist Bruchzähigkeit?
A ceramic material’s ability to resist fracture is known as fracture toughness of ceramics. It is generally described in terms of Megapascals times meter squared (MPam2). Fracture toughness is also known as the Critical stress intensity factor , calculated by the expression:
is fracture toughness, is the geometric factor,
is the stress applied and
ist die Risslänge
Es gibt mehrere Möglichkeiten zur Messung Bruchzähigkeit. One such widely used fracture toughness test is Charpy V notch. This test measures the impact on a V or U type notch.
Comparing fracture toughness of Zirconia
Zirconia properties are numerous. They work at a temperature range of 1500degc and above. Zirconia hardness Vickers is around a value of 1350Kg/mm2. It also offers low thermal conductivity and good chemical resistance.
Another important property of Zirconia is Fracture toughness that tells us about performance under applied conditions. For instance, even the best ceramic material cannot often guarantee performance. It is often a subject to the voids and defects in its lattice formed during manufacturing. Let’s see how Zirconia is distinct in terms of fracture toughness.
Bruchzähigkeit von Aluminiumoxid:
- For alumina it is in the range of 3.3 to 4.5 MPam1/2. The values might vary depending upon the grain size of the material formed and sintering used. The deviation in Bruchzähigkeit values also will result in varying performance of the material. For example, a densely sintered alumina is comparatively brittle.
Bruchzähigkeit von Glas:
- Generally, fracture toughness of glass would be as low as 0.6 and as high as 0.8 MPam1/2. This is dependent upon the type and thickness of a glass material.
Bruchzähigkeit von Zirkonoxid:
- Zirconia is famous for its durability and wear resistance. The fracture toughness of Zirconia is around 17 MPam1/2. There are factors that affect toughness value, so as the performance of zirconia. Some of them are grain size, Yttria content, Sintering and Post sintering operating parameters.
- For example, Zirconia ceramic knife is currently used as an alternative to steel knives. These are made of solid-state sintering which makes them durable and superior.
- Given is a comparison table of fracture toughness of ceramics. Zirconia tops the list followed by Silicon Nitride.
Application of Zirconia
Zirkonia-Produkte find a place in a variety of engineering applications due to their unmatchable fracture toughness and other superior properties. Some prominent usages are described below.
Zirkonoxid in der Zahnmedizin
Types of Zirconia in dentistry ranges from implants, crowns to orthodontic materials. Zirconia ceramic crowns form an integral part of cosmetic treatments. Zirkonoxid-Zahnmedizin crowns offer higher fracture resistance even at a thickness of 0.5 mm. This exceeds the maximum biting force value of 1000.
Zirkonia-Keramikkrone offers benefits of no stain. It is biocompatible and helps preserve tooth without metal. However, it suffers certain problems. Probleme mit Zirkonkronen include immediate tooth wear and fracture. This It also sometimes creates tooth sensitivity in patient sensitivity in patients and offers minimum translucence.
Pic: Zirkoniakrone vorher und nachher treatment photos
Zirkonia vs. Porzellanbrücke
While Comparing Zirconia and porcelain bridge, we should consider aesthetics, lifespan and strength of the material. Porcelain is known for their good aesthetics whereas Zirconia bridge offers higher lifespan. In appearance, Porcelain bridges are translucent and matches the existing teeth color. Zirconia is strong with fewer chipping and grinding problems when compared to porcelain bridges.
Zirconia Products in Industry
Yttriumstabilisiertes Zirkonoxid
- The Yttrium stabilized zirconia (YSZ) offers numerous properties such as superior mechanical strength. It offers excellent optical and ionic properties. YSZ is used in the manufacture Zirconia plates that can handle temperatures of 2000 degrees or above. With 8 mol% of Yttria, polished zirconia plates are chemically inert and abrasion-resistant.
- Yttriumstabilisiertes Zirkonoxid (YSZ) also serves as a refractory material. It provides good thermal insulation and can handle heat at higher temperatures.
- YSZ is also used in the manufacture of solid oxide fuel cell. It can function at a temperature of 800 – 1000 degC and serves as a good electrolyte material.
- They also form wear resistant coating and forms as an ingredient of DIY cement.
Zirconium substrate
Zirconia substrates are advanced material that are rigid. They are used in microelectronics and power electronics. It is often made at the highest purity. Zirconia substrates are stable at around 1500 degC and above.
Zirconia substrates offer high temperature resistance and are good insulators. On the other hand, the dielectric losses are minimal and the value of dielectric constant is on lesser side. Zirconia substrates also offer compatibility with existing PCB’s and electronic circuits.
Zirconia ceramic jewellery
Zirconia ceramic give rise to man cutting edge lightweight jewelry. It reduces the component cost without compromising on elegance. Zirkonia-Diamanten on the other hand are cost-effective and serves as a better alternative to real diamond. Although diamond tends to sparkle more profoundly Zirconia diamonds are no less an alternative for a better jewellery material.
Advantages of using Zirconia jewelry
- Zirconia ceramic jewelry is cost effective. They are 80% lesser in comparison to the cost of 14 KT gold
- Zirconia can be worn as a long tern trendy material. It suffers lesser wear and tear
- It has a hardness value of around 8.9. They are highly scratch resistant in nature
- The color variations pertaining to Zirconia ceramic are numerous. They are also environment friendly.
Abschluss
Zirkonoxidkeramik sind hochwertige Hochleistungskeramiken mit hervorragender Bruchfestigkeit oder Bruchzähigkeit. They remain to be dominant in the industry due to their unmatchable thermophysical properties. It is environment friendly and provides durability. Since the impact resistance offered is high, they can be deployed in hard-wearing and high-temperature scenarios.