The key difference between zirconia and aluminum oxide is that zirconia occurs in a monoclinic crystal structure while aluminum oxide is in a trigonal crystal structure.
Zirconia and aluminum oxide are inorganic compounds and are oxide compounds. Both these compounds occur in the white crystalline solid-state at standard temperature and pressure.
CONTENTS
1. Overview and Key Difference
2. What is Zirconia
3. What is Aluminum Oxide
4. Side by Side Comparison – Zirconia vs Aluminum Oxide in Tabular Form
5. Summary
What is Zirconia?
Zirconia is an inorganic oxide compound having the chemical formula ZrO2. Its chemical name is zirconium oxide; it has two oxygen atoms per one zirconium atom in a molecule. It appears as a white crystalline solid, having a monoclinic crystal structure. However, we can produce cubic structured zirconia with different colours to use as gemstones. We can produce zirconia by calcining zirconium compounds, using its property of high thermal stability.
Figure 01: Zirconia
Moreover, this compound can occur in three major crystal structures at different temperatures: monoclinic, tetragonal and cubic. However, most stable and naturally occurring form is a monoclinic structure. Chemically, this compound is unreactive, but strong acids such as HF and H2SO4 can slowly attack it. Further, if we heat this compound with carbon, it converts into zirconium carbide, and if there is chorine as well, then it forms zirconium tetrachloride. This reaction is the basis for purification of zirconium metal.
When considering the uses of zirconia, it is mainly useful in the production of ceramic, as a refractory material, as an insulator, as abrasives and enamels, etc. Moreover, its high ionic conductivity makes it useful as electroceramic material.
What is Aluminum Oxide?
Aluminum oxide is an inorganic oxide compound having the chemical formula Al2O3. It is the most stable and naturally occurring oxide of aluminum. Commonly, we call it alumina. Naturally, this compound occurs in crystalline, alpha polymorphic phase. It appears as a white solid, and its crystal structure is trigonal. Moreover, corundum is the naturally occurring form of aluminum oxide.
Figure 02: Aluminum Oxide
When considering the properties of this compound, it is an excellent electrical insulator, insoluble in water, resistant to weathering and protects the aluminum metal surface from further oxidation. Moreover, it is an amphoteric substance. That means; it can react with both acids and bases to undergo neutralizing reactions forming salt and water.
There are many applications for aluminum oxide:
- As refractory material
- For the production of ceramic and abrasives
- As a filler for plastics
- As an ingredient in glass
- For the removal of water from gas streams
- As a catalyst for many organic synthesis reactions
- As a component in paints, etc.
What is the Difference Between Zirconia and Aluminum Oxide?
Primarily, Zirconia is an inorganic oxide compound having the chemical formula ZrO2 while Aluminum oxide is an inorganic oxide compound having the chemical formula Al2O3. But, above all, the key difference between zirconia and aluminum oxide is that zirconia occurs in a monoclinic crystal structure while aluminum oxide is in the trigonal crystal structure.
Moreover, zirconia is slightly basic because it reacts slowly with strong acids such as HF and sulfuric acid; however, aluminum oxide is amphoteric, and it can react with both acids and bases to form a salt and water. Also, a further difference between zirconia and aluminum oxide is their reactivity. Chemically, zirconia is unreactive, but aluminum oxide is reactive.
Summary – Zirconia vs Aluminum Oxide
Zirconia is an inorganic oxide compound having the chemical formula ZrO2 while Aluminum oxide is an inorganic oxide compound having the chemical formula Al2O3. The key difference between zirconia and aluminum oxide is that zirconia occurs in a monoclinic crystal structure while aluminum oxide is in the trigonal crystal structure.
Reference:
1. “Aluminum Oxide.” National Center for Biotechnology Information. PubChem Compound Database, U.S. National Library of Medicine, Available here.
Image Courtesy:
1. “ZrO2powder” By Materialscientist at the English language Wikipedia (CC BY-SA 3.0) via Commons Wikimedia
2. “Aluminium oxide2” By Aluminium_oxide2.png: Nbrittonderivative work: Materialscientist (talk) – Aluminium_oxide2.png (Public Domain) via Commons Wikimedia