Wear Resistance of Zirconia Vs Alumina Ceramics

Introduction

Engineers today turn to Zirconia and Alumina ceramics for applications demanding high wear resistance. Why? It’s because these two are excellent abrasives in the advanced ceramics industry. Interestingly, they have similar properties, which makes it tough for engineers, manufacturers, and some orthopedists to choose the better between them. You are probably now wondering - so, what is the most wear-resistant ceramic? Today’s article will answer this popular question and also show you some key properties that make Zirconia and Alumina excellent in resisting wear and tear. You will learn about their performance standards and know their differences. Let’s dive right in!

Wear Resistance of Zirconia And Alumina Ceramics

Wear and tears caused by friction have made so many companies and industries today look out for technical ceramic materials with a strong ability to resist or reduce the impact of friction, wear, and tear. Zirconia and Alumina ceramics are very tough materials that can withstand heavy-duty jobs. Zirconia’s resistance to wear and tear is so strong that it can effectively preserve the life and performance standards of your equipment. Just imagine a ceramic material that is not so bulky, yet doesn’t break easily. It’s so tough that even in outrageous temperatures reaching 2,100°C, you would still have to go through a rigorous process to crack it. You’d agree that industrial machine parts working tirelessly for hours in heated conditions are at risk of wear and tear due to constant friction. So, what other material would you consider in coating or producing some of these machine parts if not Zirconia?

Alumina is another very hard material, having similar properties to Zirconia. It’s one of the few advanced ceramics that can go toe-to-toe with zirconia on the market. As a matter of fact, it has a brilliant rating of 9 on the Mohs hardness scale, and its wear resistance is also impressive. This means, like zirconia, you can also use it to make tough machine parts. However, Alumina ceramics tend to conduct heat and electricity slightly better than zirconia; they both still have outstanding resistance to wear and tear. So, as an orthopedic surgeon, a dentist working with enamels and dentals in the hospital, an engineer or manufacturer looking to produce heavy machines, vehicle spare parts, electrical and industrial equipment, which of these materials would be your best pick? Tough choice, right? Don’t worry, we’ll cover their differences with incited cases in the next sections.

Zirconia Ceramics vs  Aluminum Oxide Ceramics

Zirconia (ZrO2) Ceramics

Zirconia is a very tough crystalline ceramic material also called Zirconia Oxide (ZrO2). It’s formed as an oxide of Zirconium and exists naturally in a form called Baddeleyite and has an appearance of ivory white or yellowish colour. Zirconia products are outstanding and regarded as the best abrasives in the ceramic market due to their high strength and stability, strong resistance to extremely high temperatures, fractures, mechanical stress, and corrosive chemicals. Their unusually high density and wear resistance can help you achieve maximum results even in unfavourable conditions. Zirconia ceramics in their different shapes and sizes are ideal components for refractory, bearings, heavy machine parts, electronics, automobile, and aerospace applications.

It changes into different forms when in contact with high temperatures, hence the use of stabilizers like Yttria and Ceria. This answers for the availability of different grade types like Zirconia Toughened Alumina (ZTA), Magnesia stabilized Zirconia, Yttria stabilized Zirconia, and Ceria stabilized Zirconia. Somehow, it’s been discovered that Zirconia is highly biocompatible, and because it doesn’t wear out easily and will not react negatively with chemicals in the body, surgeons and orthopedic surgeons now utilize it in bone and teeth-related cases.

Zirconia today has become a commercial product with high demand despite being very costly, hard to find, and produce, recording global sales of over $900 million, mainly due to its excellent ability to withstand wear and tear. Market makers are now projecting a Compound Annual Growth Rate (CAGR) of 6%. It’s safe to say you can produce Zirconia ceramics using several methods, like thermal calcination, chlorination, carbiding, using sodium hydroxide (NaOH) or sodium bicarbonate (NaCO3) to decompose the naturally occurring form under high temperatures of about 2,800°C. If you are not open to production yet, you can purchase zirconia ceramics from us at GGSCeramics. We’ve been reliable suppliers of some of the best zirconia products you can find out there.

Properties of Zirconia Ceramics

Now, some properties of Zirconia (ZrO2) that make it really enticing and wear resistant are:

• It has a solid fracture toughness rating of 10 MPa·√m.

• Its Vickers Hardness is 1,220 and 8.5 on the Mohs Hardness scale.

• At 20°C, its flexural strength is between 180 MPa and 1000 MPa.

• It has an elastic modulus of about 250 GPA.

• It has a melting point ranging from 1170°C to 2,700°C.

• It has a very high compressive strength, toughness, and biocompatibility.

• It has a density of up to 6.2G/Cc.

• It possesses a dielectric strength of about 300V/mil.

• It has a volume resistivity of 5 x 10-3 at temperatures reaching 700°C.

• At 20°C, it possesses a magnificent tensile strength of 300 MPa.

• It has a zero percent water absorption rate.

• It possesses a high level of shock resistance and thermal conductivity of 3.5W/mk.

Industrial Applications of Zirconia Ceramics

Some ideal cases where you can use these Zirconia ceramics products are:

• The medical field in the production of enamels and bones

• Mechanical engineering applications that come with high stress and intense working temperatures or environments

• Production of ball bearings and heavy machine rings

• Production of electronics parts

• Aerospace applications

• Production of grinding Jars, media, or Mortars, especially with the aid of Zirconia Toughened Alumina grade type.

• Production of other structural ceramic parts in valves, pumps, and analytical instruments

Alumina (Al2O3) Ceramics

Alumina ceramics, also known as Aluminum Oxide (Al2O3) ceramics, are made industrially from Aluminum and Oxygen. It’s a white or sometimes pinkish crystalline compound commercially called Corundum, although you can produce it mainly from Bauxite, its naturally occurring form. Like Zirconia, Alumina is also a very brilliant, wear-resistant technical ceramic option. It’s a cheaper alternative to Zirconia with a wide range of chemical and electrical properties that make it useful to so many industries. Fun fact is, these properties can be improved upon if you use additives in the production process. Some of the various production processes include slip casting, diamond machining, isostatic pressing, and injection moulding.

Alumina ceramics are great at resisting corrosion, wear, and tear because of the highly pure aluminum used in producing them. Which means the higher the pure alumina content in them, the better the wear resistance and thermal conductivity. Meanwhile, different grades of alumina ceramics exist; examples are hydrated alumina, calcined alumina, tabular alumina, etc. These are all based on the aluminum oxide content, various components, and additives used by the manufacturer.

Alumina ceramics are now gaining so much popularity in the global ceramics market due to the several great properties they possess. Some of them are:

• A fracture toughness of 4.5 MPa·√m

• An elastic modulus of 400 GPa

• Its ability to withstand temperatures up to 2,000°C

• A density of 3.965g/cm3

• A very high compressive strength of about 3,500 MPa

• Its ability to withstand attack from strong acids or alkalis, even at high temperatures

• A high thermal shock resistance and thermal conductivity

• A hardness rating of 18 GPa

• A tensile strength of 200 MPa

• A flexural strength between 500-600 MPa at 25°C

• A thermal conductivity of 45W/mK at 25°C

• A dielectric strength of 16kV/mm at 25°C

• A volume resistivity that ranges from 10¹⁴ and 10¹⁶.

Industrial Applications of Aluminum Oxide Ceramics

Some of the ways you can apply and successfully utilize the wear resistance of alumina ceramics are:

• You can produce heavy wear components like tap valves and industrial machine parts

• Production of electrical components and high-voltage insulators

• Production of machine components like ball bearings, laser tubes, rollers, seal rings, precision shafts, etc.

• You can get useful semiconductor parts from alumina ceramics

• It can help you produce blast nozzles and furnace linings

• The military utilizes it for the production of bullets, bulletproof vests, ballistic armor, and thermocouples.

• Aerospace and Automotive industries utilize alumina ceramics in the production of vehicle spare parts and spacecraft.

Comparison Between Zirconia Ceramics and Aluminum Oxide Ceramics

From the discussion so far, the question of the most wear-resistant ceramic has been sorted out. You’ve seen how technically sound these two ceramic materials are. The fact is, Zirconia gains the upper hand as a better and more durable wear-resistant ceramic for high precision technical applications despite the heavy cost of purchase and production. While Alumina is a cheaper and more commonly used option for less demanding applications. Here is a table that shows the clear difference between the wear resistance of Zirconia and Alumina ceramics.

So, Zirconia vs Aluminum Oxide ceramics, the choice is up to you. Depending on what you want and the results you intend to get from your application, either as a doctor, engineer, or someone looking to get great wear-resistant ceramic materials.

Frequently Asked Questions

Why is Zirconia Oxide (ZrO2) not a good thermal conductor? 

It’s because of the arrangement of oxygen atoms and zirconia in the crystal structure of ZrO2.

Can Zirconia also be called a Metal?

No, you can either call it a ceramic material or a semiconductor metal oxide because it can conduct electricity.

Which of these two ceramic materials is better for medical implants?

Zirconia tends to be more suitable for medical/surgical implants because of its tough nature, great biocompatibility, and ability to withstand extreme stress/fractures.

Conclusion

Zirconia and Alumina have paved the way for the production of equipment that can withstand absolutely any form of wear and tear. Their unbeatable reliability, whether in high-stress conditions, intense working temperatures, or sudden fractures, is something almost every manufacturer and user out there is looking for. Now is the best time for you to invest and break boundaries in global ceramics like these two heavyweights.  The good news is, you can quickly contact us at GGSCeramics for the best zirconia, Zirconia Toughened Alumina, and alumina ceramics products. Don’t wait! Join the moving train now!