Zirconium: Metal or Ceramic ?

Nowadays, there is a debate whether Zirconium is a metal or ceramic material. This post pretends to clarify the frequently asked questions from both the professionals and the patients.

Zirconium, the chemical element:

Zirconium is a chemical element with atomic number 40, located in group 4 from the periodic chart of elements. Its symbol is Zr. It is a hard metal, resistant to corrosion and similar to steel. It does not exist in nature in the pure state. It can be obtained through complex physico-chemical process. In the periodic chart, it is located next to Titanium (Ti). For this reason their properties are very similar.

Zirconium found in minerals:

The most important minerals that contain zirconium are zircon (ZrSiO4) and badeleyita (ZrO2). Zirconium is always found mixed together with Hafnium (Hf), and they are very difficult to separate them.

badeleyeita mineral badeleyita mineral

zircon mineral

Occurrence and Refining:

Zirconium has a concentration of about 130 mg/kg within the earth’s crust and about 0.026 μg/L in sea water, though it is never found in nature as a native metal. The principal commercial source of zirconium is the zirconium silicate mineral, zircon (ZrSiO4), which is found primarily in Australia, Brazil, India, Russia, South Africa, and the United States. 80% of zircon mining occurs in Australia and South Africa.

Zirconium also occurs in more than 140 other recognized mineral species including baddeleyite andkosnarite. This metal is commercially produced mostly by the reduction of the zirconium(IV) chloride withmagnesium metal in the Kroll process. Commercial-quality zirconium for most uses still has a content of 1% to 3% hafnium.

Cantera de zirconio. Australia. Zircon mine. Australia

zircon sand.

This zircon sand is the raw material to obtain pure METAL (Zr 99%) and the Zirconium oxide CERAMIC (ZrO2) .

Production of Pure Metal Zirconium  (Zr 99%):

Zirconio puro Crystal Bar

To obtain the pure metal, the process “Van Arkel” is used to obtain a zirconium sponge called Zirconium crystal-bar.

The “crystal-bar” can be melted to obtain the zirconium rod or ingot. The pure zirconium is mainly used in the nuclear reactors as containers for the nuclear fuel, and also to form compounds highly resistant to corrosion.

Zirconia rod. pure Zr 99%

This metal is grey, shining and very resistant to corrosion. It is lighter than steel, and hardness similar to copper.

Production of zirconium oxide ceramic = Zirconia = ZrO2

Zirconium ceramic is obtained through a reductive clorination (Kroll process). At the end of this process, one can obtain zirconium oxide powder (which is a ceramic and no longer a metal).

Zirconia (ZrO2) = zirconium ceramic

ZIRCONIA is a powder that is used as pigment for white paints, and also in the abrasives. At room temperature presents a monoclínic phase. This cofiguration is extremely fragile.
To improve the properties of zirconia (ZrO2), other elements are added to the compound to stabilize the molecular structure: ex. Yttrium (Y). Through a mixture and sintering process, the final ceramic structure is stabilized. The Y-TZP is the Yttrium stabilized Tetragonal Zirconium Policrystal.

The Y-TZP ceramic is the material that is used in dentistry as ZIRCONIA (not ZIRCONIUM). Simply, it has been always easier to say zirconium than Y-TZP.

CeraRoot Zirconium Oxide implants (Y-TZP)  and  de zirconium prosthetics (Y-TZP) with porcelain for final color characterization.

Zirconium properties

METAL  vs  CERAMIC

METAL  Zr 99%

  1. Color metal grey
  2. Weak metallic bonds
  3. Maleable
  4. Ductile
  5. Wear
  6. Thermic conductor
  7. Electric conductor
  8. easy oxidation
  9. chemical corrosion
  10. used in nuclear reactors

Y-TZP CERAMIC  (ZrO2)

  1. Color white
  2. Strong cobalent bonds
  3. Hard
  4. Fragile
  5. Wear resistant
  6. Thermic insulator
  7. Electric insulator
  8. Oxidation resistant
  9. No chemical corrosion
  10. Used in technical ceramics

15 thoughts on “Zirconium: Metal or Ceramic ?

  1. Does the ceramic still carry traces of metal? I’m a really allergic to metal and always had a porcelain cap. It broke and I told my dentist no metal or nickel. They made this for me and I have a awful taste in my mouth and feels like I’m having a reaction to the new cap. Dentist is telling me no it can’t be but….

    1. Hello Stephanie, when the crowns are ALL-CERAMIC, there are no metal parts or metal chemical composition in them. We don’t know what material was used for your crown. Can you ask the doctor the exact composition of the crown? Once we receive your message we will be able to tell you more details.

  2. If I am highly reactive to Zirconium, will I also be reactive to Zirconia? Or is there a separate test for that? Kindly advise.

    1. Zirconium is a metal. Zirconium oxide is a ceramic. You could be allergic to Chloride (Cl) but would perfectly tolerate Sodium Chloride (NaCl) which is the common salt that you use at home in the kitchen for cooking. So Yes, you could be allergic to zirconium and also allergic to zirconium oxide but they are two completely different materials, it’s almost impossible, because ceramics do not corrode and release oxides (rust) in your gum or skin, whereas metals easily can be attacked by liquids and become corroded and release metal microscopic particles in the surrounding tissues and in the long term create allergy. I have never heard of anyone being allergic to a ceramic/porcelain coffee/tea cup. But there are many persons that their skin reacts when in contact with metal jewelry.

  3. Almost every dentist that I speak with about the Zirconia implants tells me not to get them due to the breakage capacity. If they break you have to drill out a lot of bone to get the implant out and replace it. They also tell me that because they are a one piece implant you cannot move them once they are implanted to change they angle incase they are not getting proper occlusion

    1. Hello Dean, there is a group of dentist that are listed on our website on the “Find a Dentist” section as well as on Youtube, that are very happy to have other options besides metal titanium implants. Our implants are more strong than two piece titanium implants and the first implants were placed 13 years ago in Europe and are still functioning perfectly. We publish on the website once in a while patients that come for follow-up after 5 or 10 years and we are very happy to see they have no problems. Doctors who perform surgeries with titanium implants also encounter problems with the system they are using. Every patient is different and every product is different, and whoever says, titanium implants do not experience problems or failures is not saying the truth. Titanium implants break sometimes or the crown that is screwed on the implant sometimes keeps getting loose because there are small tolerances that affect the performance of the product.

    1. Hello Freya,

      CeraRoot is a ceramic implant and it’s made of zirconium oxide (or zirconia). When we talk about zirconium oxide, it is a ceramic. When we talk about Zirconium (alone… without the word “oxide”) then it is a metal. To summarize: zirconium is a metal and zirconium oxide is a ceramic. And CeraRoot is made of zirconium oxide which is a ceramic. CeraRoot does not contain any metal part.

    2. Hello Freya, zirconium oxide implant is the same as ceramic implant. If you read somewhere about “Zirconium implants” (instead of zirconium oxide) without the “oxide” word it is probably the same… but they are also referring to ceramic implants.

      Zirconium (alone) is a metal…. but there are websites that forget to put the word Oxide behind and they can make confusion. The best option is to search for “ceramic implants” or “zirconia implants” or “zirconium oxide implants”.

    1. Hello Oskar, inside the composition of the CeraRoot, 95% is Zirconium Oxide (a ceramic) and the rest (approximate) 5% is Yttrium-Oxide (a ceramic).

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