Updated by Reginald Davey 22/11/22
This article will provide a brief overview of titanium, its uses, and a comparison with other key metals.
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A direct comparison of the physical, electrical, and thermal properties of pure titanium with those of other metals such as aluminum, nickel, magnesium, copper, and 304 stainless steel is illustrated in Table 1.
Titanium – An Overview
Titanium is a silvery grey metal belonging to Group 4 in the periodic table. This eminently useful industrial metal is lightweight, has high strength, and does not corrode easily in normal environmental conditions.
Discovered in compound form in 1791 by William Gregor, an English mineralogist and chemist, it was rediscovered independently by Martin Heinrich Klaproth, a German chemist, in 1795. Klaproth named the element. It was first isolated in its pure form by Matthew A. Hunter in 1910.
Titanium is a widely abundant element, comprising around 0.44% of the Earth’s crust. This element is found in nearly all sand, clays, soils, and rocks. It is also found in biological organisms, natural waters, material dredged from the deep sea, meteorites, and stars.
The two main commercial titanium-containing minerals are rutile and ilmenite. A highly-reactive element, the preparation of titanium is challenging. At elevated temperatures, titanium is extremely reactive toward nitrogen and oxygen, and moreover conventional oxidative reduction methods do not obtain titanium.
A paramagnetic material, titanium has two crystalline structures that exist at different temperatures. Below 883oC, it has a hexagonal close-packed structure, and above this temperature, it forms a body-centric cubic crystal structure. Five stable isotopes exist: titanium-46, titanium-47, titanium-48, titanium-49, and titanium-50.
Is Titanium Conductive?
A key property in many industrial materials is their electrical and thermal conductivities. Titanium has relatively low electrical and thermal conductivity compared to other engineering metals and alloys. The low electrical conductivity of titanium makes it ill-suited to applications where this is a prime consideration.
The low thermal conductivity of titanium is a key consideration during machining processes. When machining titanium, the tool can heat up instead of heat being distributed evenly, which can affect the quality and lifetime performance of machining tools.
Properties
A direct comparison of physical, electrical, and thermal properties of pure titanium with those of other metals such as aluminum, nickel, magnesium, copper, and 304 stainless steel is illustrated in Table 1.
Table 1. Comparison of physical properties of titanium with those of other metals.
| Property |
Titanium |
304 Stainless Steel |
Aluminum |
Magnesium |
Nickel |
Copper |
| Atomic No. |
22 |
-- |
13 |
12 |
28 |
29 |
| Atomic Wt. |
47.867
|
--
|
26.981
|
24.305
|
58.6934
|
63.546
|
| Specific Gravity |
4.54
|
7.93
|
2.7
|
1.74
|
8.91
|
8.9
|
Linear thermal
expansion coefficient (/°C) |
8.4X10-6 |
17X10-6 |
23X10-6 |
25X10-6 |
15X10-6 |
17X10-6 |
|
Specific heat capacity (J/g K)
|
0.52
|
500
|
0.9
|
1.02
|
0.44
|
0.38
|
Thermal conductivity
coefficient (cal/cm2/sec/°C/cm) |
0.041 |
0.039 |
0.49 |
0.38 |
0.22 |
0.92 |
Specific electrical
resistance (µOhm-cm) |
55 |
72 |
2.7 |
4.3 |
9.5 |
1.7 |
| Electrical conductivity (%IACA) |
3.1 |
2.4 |
64 |
40 |
18 |
100 |
| Young's modulus (kg/mm2) |
10850 |
20403 |
7050 |
4570 |
21000 |
11000 |
| Poisson's ratio |
0.3
|
0.3
|
0.33
|
0.35
|
0.31
|
0.36
|
| Melting Point (oC) |
1600 |
1400-1450 |
660.32 |
640 |
1455 |
1085 |
Passivation of Titanium
Titanium is a highly reactive metal, much like aluminum. However, titanium can be rendered inert by atmospheric passivation and the formation of a surface oxide layer. This process can occur in both air and water. The oxide layer makes titanium immune to attack by mineral acids such as sulfuric and hydrochloric acid. This chemical resistance can be further enhanced by incorporating palladium.
Titanium – Industrial and Commercial Applications
Titanium’s outstanding corrosion resistance, high strength, and low density makes it an ideal material for industrial applications such as missile, ship, aircraft, and spacecraft parts. Another key application of this material is in medical science, where it is commonly applied in prostheses due to its lack of reactivity with organic tissues.
Titanium has been applied as an alloying material for steelmaking to reduce steel’s grain size and a deoxidizer, as a carbon-reducing additive in stainless steels, additives for hardening copper, and to reduce grain size in aluminum.
304 Stainless Steel Vs Titanium
Both of these metals are widely used in commercial and industrial applications. 304 stainless steel is an austenitic steel that contains 8-10.5% nickel and 18-20% chromium by weight. With good welding and forming properties and corrosion resistance, 304 stainless steel is used for applications such as heat exchangers, piping, bolts, screws, commercial kitchen equipment, and automotive trims and moldings.
The properties of both industrial materials govern their different commercial uses. Titanium’s hardness is less than 304 stainless steel, but titanium is 3-4 times stronger than stainless steel, which gives it a longer lifespan. 304 stainless steel is more elastic than titanium, and has an ultimate tensile strength greater than that of titanium.
Titanium also possesses a higher strength-to-weight ratio than stainless steel grades. Titanium is also biocompatible, whereas 304 stainless steel is not, which limits the use of stainless steel in medical applications, which are a key industrial use of titanium. 304 stainless steel is much cheaper than titanium. Both metals are recyclable.
In Summary
Titanium is an industrially important metal that is used in a wide variety of commercial applications. Its unique properties make it more suitable than some other industrial metals for certain applications, whereas its poor performance in areas such as electrical and thermal conductivity limits its use somewhat, making materials such as copper more favorable. This article has been a brief overview of titanium and its comparison with some other industrial metals.
More from AZoM: Titanium and Titanium Alloys - Forming and Formability of Titanium and Titanium Alloys
Further Reading and More Information
Lead (2022) Stainless Steel Vs. Titanium: Differences Between These Two Metals [online] leadrp.net. Available at:
https://leadrp.net/blog/stainless-steel-vs-titanium-differences-between-these-two-metals/#Advantages_of_Stainless_Steel
Solid Carbide Tools (website) Titanium Properties [online] Kyocera-sgstool.co.uk. Available at:
https://kyocera-sgstool.co.uk/titanium-resources/titanium-information-everything-you-need-to-know/titanium-properties/
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