Why Corrosion Resistance is not the Most Important of Titanium Properties.
You’ve boarded the aircraft on your way to that sales meeting in Atlanta. You tuck your new Taylormade Golf driver –200 grams of ball crushing titanium salvation—into the overhead bin and settle into your seat.
The Boeing 777 surrounds you with no less than 20,000 pounds of titanium. By weight, approximately 9% of today’s crash free flight will be brought to you by titanium and its alloys. Time to flip your titanium carbo-nitride coated Sony cell phone to airplane mode as the General Electric Titanium and Titanium Aluminide turbofan engine blades spin to life. Yeah. Titanium makes life good.
The Many Faces of Titanium
So what do aerospace engineers, golf club designers, petroleum engineers, and consumer electronics marketers find so attractive about titanium? The Earth’s natural order gave titanium all the right stuff:
It’s Light: Titanium is one of 38 transition metals on the periodic table of elements. Unlike other useful elements like iron, nickel, and cobalt, titanium lies on the extreme light end of the chart. It has relatively few electrons, protons, and neutrons –the particles that give atoms their mass. As a result, the titanium atom weighs in lighter than 36 of the 38 transition metals.
To learn more about why titanium is light, read our article about titanium aerospace castings.
It’s Tough: Now take those lightweight atoms and stack them together to form a titanium crystal. Nature packs them together in a three dimensional hexagon–the most efficient, stable, and stress resistant of the metallic crystal structures. This gives titanium its natural strength to temperatures of about 800 degrees Fahrenheit.
It’s so Reactive that it’s Stable. (Huh?) It’s a paradox alright, but titanium’s atomic structure makes it want to react chemically. So much so, in fact, that bare titanium reacts with oxygen in the air to form an invisible, nanometers-thin oxide layer on its surface. That layer is so tough and impenetrable it protects the underlying metal from reacting with anything else. That makes titanium incredibly useful to prevent seawater corrosion and to prevent chemical corrosion.
There’s a LOT of it! Titanium is 9th most abundant element in the earth’s crust. It’s found in almost all igneous rocks (think “volcano stuff”) and is a major export for Australia, Canada, South Africa, and the Ukraine.
The Applications for Titanium
Even in its unalloyed pure form titanium is a useful and widely applied structural metal. Add alloying elements like aluminum and vanadium, and it becomes a favored choice of engineers:
Jet engine fan and compressor blades, engine nacelles, airframe structures
Military and Defense
Airborne weapons systems, missile components, firearms
Surgical implants, including spine, hip, knee, shoulder, and ankle components, surgical tools and machinery; Dental equipment
Automotive and Heavy Equipment
Turbocharger compressor wheels, turbine wheels, valves, exhaust components
Hammers, Pry Bars, Hammer Drill components, and other construction tools
Golf clubs, bicycles, tennis rackets, laptop and cell phone chassis’
Marine and Seawater Applications
Undersea surveillance devices, propeller shafts, saltwater heat exchangers, oil exploration, oil and gas recovery, and seismic mapping
Petrochemical processing of
- Oxidizing Chlorides
- Pure Terephthalic Acid (C6H4(CO2)H)2) – PTA
- Hydrobromic Acid (HBr)
- Sulfuric Acid (H2SO4)
- Phosphoric Acid (H3PO4)
What are the Benefits of Titanium?
Any application that can benefit from titanium’s strength, light weight, corrosion resistance, and market appeal is a candidate for a precision titanium casting.
Strength-to-Weight Ratio: Some titanium alloys can be as strong as many common steels, but 40% lighter. An as-cast titanium part provides a strength-to-weight ratio one and a half times greater than cast and heat treated stainless steel, and twice that of aluminum. This allows designers to trim weights and section thicknesses while optimizing strength.
Titanium has found most of its applications in products converted from steel & aluminum alloys. See our article for to discover the answer to the question “why is titanium lightweight?”
Corrosion Resistance: Titanium is nearly as resistant to chemical attack as platinum! It finds extensive usage in seawater and chemical handling components.
Market Appeal: Companies ranging from American Express to Blackberry have spent millions of marketing dollars reinforcing the image and value associated with titanium. All manner of consumer markets have taken advantage of titanium’s ample sex appeal. It often outperforms the precious metals in the marketplace by virtue of its technical appeal.