ZIRCONIUM EXHIBITS EXCELLENT RESISTANCE TO CORROSION IN MOST ORGANIC AND INORGANIC SOLUTIONS.
Zirconium is a reactive metal that owes its corrosion resistance to the formation of a chemically inert, tenaciously adherent oxide film. It is particularly resistant to reducing acids and strong alkalis. It is also resistant to strong nitric acid, some molten salts and is used in heat exchangers, valves, piping, reactor vessels, tanks, pumps, tower packing and laboratory equipment.
Zirconium is our most effective crucible material for fusions using sodium carbonate or sodium peroxide. It is an excellent low-cost replacement for platinum. And, based on an average of 100 fusions per crucible, it is more cost effective than less expensive porcelain or steel crucibles. The major use of zirconium remains in the nuclear reactor arena. The thermal neutron capture cross-section is extremely low so the metal acts as a window to these particles. It also exhibits good corrosion resistance to the aqueous media within the operational nuclear reactor.
PROPERTIES
Zirconium is a reactive metal; it has a high affinity for oxygen and as such forms a protective oxide film that enables it to perform well in a wide variety of conditions.
- Atomic No. 40
- Atomic Wt. 91.22
- Specific Gravity 6.51
- Melting Point 1852˚C
- Coefficient of Thermal Expansion 5.8 X 10-6/°K
- Specific Heat 0.066 cal/g/°K
- Ultimate Tensile Strength (Room Temperature, Annealed) 55 ksi
- Yield Tensile Strength (Room Temperature, Annealed) 30 ksi
- Poisons Ratio 0.35
- Modulus of Elasticity 14.4 X 106 psi
- Stress Relief Temperature 565˚C
GENERAL CORROSION RESISTANCE
Zirconium exhibits superb corrosion resistance in most organic and inorganic acids, salt solutions, strong alkalis and a few molten salts. The passive oxide film (corrosion barrier) is stable in both reducing and oxidizing conditions. Zirconium is excellent in both acidic and basic solutions. The temperature limit for use in air is about 450˚C to 500˚C.
This data is based on laboratory testing only. Your in-plant results may differ. Testing is recommended under other conditions as needed.
READ CAREFULLY BEFORE USING CRUCIBLES
IMPORTANT: To ensure maximum crucible life and safety of the operator, read instructions carefully before performing fusion.
Oxidation is not a serious problem with zirconium in sodium peroxide fusions. With sodium or potassium carbonate fusions, the reducing flame of a Bunsen burner (except for finishing the fusion) is far preferable to a muffle furnace.
NEVER use a muffle furnace with zirconium unless a blanket of inert gas such as argon or helium is also used.
Zirconium metal reacts, when heated in air, to form a dark mixed surface layer of oxide plus nitride. It is not necessary to remove this layer between successive fusions. If occasional scouring becomes necessary, fine zircon sand has proven most effective. Crucible cleaning kits are available: Part Number: 90-100.
For best results in peroxide or peroxide-plus-carbonate fusions, use a finely ground sample and about ten times the sample weight of flux material. Mix well. Fusion should be completed 2 to 3 minutes after melting begins at 600-700°C. Gentle swirling of the molten mixture at room temperature and while cooling accelerates decomposition of sample and increases life of crucible.
DO NOT EXCEED 900°C or zirconium crucibles will enlarge and oxidize (turn pinkish white).
CORROSION RESISTANCE OF ZIRCONIUM
Zirconium's resistance to corrosion by many materials is exemplified in the following table.
|
Solution |
Concentration in Weight % |
Temperature in °F |
Corrosion
Resistance(mpy) |
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|
|
|||||
| Acetaldehyde | 100 | Boiling |
2 |
||
| Acetic Acid | 5, 25, 50, 75, 99.5 | Boiling |
1 |
||
| Acetic Acid | Vapor - 33 | Boiling |
5 |
||
| Acetic-Glacial Acid | 99.7 | Boiling |
5 |
||
| Acetic Anhydride | 99 | Room to Boiling |
2 |
||
|
|
|||||
| Aluminum Chloride (Aerated) | 5, 10 | 140 |
2 |
||
| Aluminum Chloride | 40 | 212 |
2 |
||
| Aluminum Chloride | 25 | Room |
2 |
||
| Aluminum Sulfate | 60 | 212 |
2 |
||
| Ammonia | Plus Water | 100 |
5 |
||
|
|
|||||
| Ammonium Chloride | 1, 40 | 212 |
5 |
||
| Ammonium Hydroxide | 28 | 80 |
5 |
||
| Ammonium Sulfate | 5, 10 | 212 |
5 |
||
| Aniline Hydrochloride | 5, 20 | 212 |
5 |
||
| Aqua Regia | 3:1 | 170 |
50 |
||
|
|
|||||
| Barium Chloride | 5, 20 | 212 |
5 |
||
| Barium Chloride | 25 | Boiling |
5 to 50 |
||
| Bromine | Water | Room |
50 |
||
| Calcium Chloride | 5, 10, 20 | 212 |
5 |
||
| Calcium Chloride | 75% | Boiling |
5 |
||
|
|
|||||
| Calcium Hyprochloride | 2, 6, 20 | 212 |
5 |
||
| Calcium Hyprochloride | Saturated | Room |
5 to 50 |
||
| Carbolic Acid | Saturated | 212 |
5 |
||
| Carbon Tetrachloride | Liquid | Boiling |
5 |
||
| Chlorine (Water Saturated) | Room |
50 |
|||
|
|
|||||
| Chlorine (Water Saturated) | 167 |
50 |
|||
| Chlorine Gas (> 0.13% H,0) | 100 | 200 |
50 |
||
| Chlorine Gas (Dry) | 100 | Room |
5 |
||
| Chloracetic Acid | 30 | 180 |
5 to 50 |
||
| Chromic Acid | 10 to 50 | Boiling |
1 |
||
|
|
|||||
| Citric Acid | 10, 25, 50 | 212 |
1 |
||
| Cupric Chloride | 20, 40, 50 | Boiling |
50 |
||
| Cupric Cyanide | Saturated | Room |
50 |
||
| Dichloroacetic Acid | 100 | 212 |
5 to 50 |
||
| Dichloroacetic Acid | 100 | Boiling |
5 to 50 |
||
|
|
|||||
| Ethylene Dichloride | 100 | Boiling |
5 |
||
| Ferric Chloride | 5, 10, 20, 30 | Room |
50 |
||
| Ferric Chloride | 5, 10, 20, 30 | 212 |
50 |
||
| Ferric Chloride | 5, 10, 20, 30, 40, 50 | Boiling |
50 |
||
| Fluboric Acid | Not Recommended | ||||
|
|
|||||
| Fluorosilicic Acid | Not Recommended | ||||
| Formic Acid | 10, 25, 50, 90 | 212 |
1 |
||
| Formic Acid (Non-Aerated) | 25 | 212 |
5 |
||
| Formic Acid (Aerated) | 10-90 | 212 |
5 |
||
| Formic Acid (H2O Soution) | 9 | 125 |
5 |
||
|
|
|||||
| Hydrobromic Acid | 40 | Room |
50 |
||
| Hydrobromic Acid | 5 | Room |
1 |
||
| Hydrobromic Acid | 10 | 95 |
5 |
||
| Hydrobromic Acid | 20 | 95 |
5 |
||
| Hydrobromic Acid (Aerated) | 5 | 95 |
5 |
||
|
|
|||||
| Hydrochloric Acid (Aerated) | 10 | 95 |
5 |
||
| Hydrochloric Acid (Aerated) | 20 | 95 |
5 |
||
| Hydrofluoric Acid | (All) Do not use! | Dissolves Readily | |||
| Hydrogen Peroxide | 50 | 212 |
2 |
||
| Hydroxyacetic Acid | 104 |
5 |
|||
|
|
|||||
| Lactic Acid | 10-100 | 300 |
1 |
||
| Magnesium Chloride | 5-40 | 212 |
5 |
||
| Manganous Chloride | 5-20 | 212 |
2 |
||
| Mercuric Chloride | 1, 5, 10, 55 | 212 |
1 |
||
| Mercuric Chloride | Saturated | Room |
1 |
||
|
|
|||||
| Mercuric Chloride | Saturated | 200 |
1 |
||
| Nickel Chloride | 5-20 | 212 |
1 |
||
| Nitric Acid | 10, 20, 40, 69, 75 | 500 |
1 |
||
| Nitric Acid | 65, 75 | Boiling |
1 |
||
| Oxalic Acid | All concentrations | 212 |
1 |
||
|
|
|||||
| Phenol (Carbolic Acid) | Saturated | Room |
5 |
||
| Phosphoric Acid | 5-3 | Room |
5 |
||
| Phosphoric Acid | 35-50 | Room |
5 |
||
| Phosphoric Acid | 85 | 100 |
5 to 20 |
||
| Phosphoric Acid | 5-3.5 | 140 |
5 |
||
|
|
|||||
| Phosphoric Acid | 5-50 | 212 |
5 |
||
| Potassium Chloride | Saturated | Room |
5 |
||
| Potassium Hydroxide | 10 | Boiling |
1 |
||
| Potassium Hydroxide | 25 | Boiling |
1 |
||
| Potassium Hydroxide | 50 | Boiling |
5 |
||
|
|
|||||
| Silver Nitrate | 50 | Room |
5 |
||
| Sodium Chloride | 29 | Boiling |
1 |
||
| Sodium Chloride | Saturated | Room |
1 |
||
| Sodium Chloride | Saturated | Boiling |
1 |
||
| Sodium Hydroxide | 10, 25 | Boiling |
1 |
||
|
|
|||||
| Sodium Hydroxide | 28 | Room |
1 |
||
| Sodium Hydroxide | 40 | 212 |
1 |
||
| Sodium Hypochlorite | 6 | 212 |
5 |
||
| Stannic Chloride | 5 | 212 |
1 |
||
| Stannic Chloride | 24 | Boiling |
1 |
||
|
|
|||||
| Sulfuric Acid (Aerated) | 1-60 | 212 |
5 |
||
| Sulfuric Acid (Air-Free) | 15 | Room |
20 |
||
| Sulfurous Acid | 6 | Room |
5 |
||
| Sulfurous Acid | Saturated | 375 |
5 to 50 |
||
| Tannic Acid | 25 | 212 |
1 |
||
|
|
|||||
| Tartaric Acid | 10-50 | 212 |
1 |
||
| Tartaric Acid | 10, 25, 50 | 140 |
1 |
||
| Tetrachloroethane (Water Mix) | 100 | Boiling |
5 |
||
| Trichloroacetic | 100 | 212 |
50 |
||
| Trichloroacetic | 10-40 | Room |
2 |
||
|
|
|||||
| Trichlorethylene | 99 | Boiling |
5 |
||
| Trisodium Phosphate | 5, 20 | 212 |
5 |
||
| Zinc Chloride | 10 | Boiling |
5 |
||
| Zinc Chloride | 20 | 212 |
5 |
||
|
|
|||||
| Mpy = mil. per year - 1 mil. = .001 inches | |||||