Conceived beneath the skies of the ancient world, the Titans were the incestual god-lineage of Zeus: gigantic creatures who bore names like Oceanus, Themis, Hyperion. The metals then known to man were those purest of elements, and it was some two millenia before titanium would be discovered and used.
With an unmatched strength-to-weight ratio, low thermal conductivity and a tendency to be impervious to corrosion, titanium is indeed a metal of mythical proportions, even to the point of being mythically difficult to work with. Titanium is what we use when we want to physically bond and repair the human body, it is what the hulls and appendages of our deep sea vessels are made of, it is the metal of engines that rocket our ships with ripping heat into space. For many reasons, it is considered nearly invincible, much like the hulkish gods it was named for.
First culled forth from the black sands of the Helford River back in 1791 — a veritable heyday for the discovery of elements — titanium was brought to light by one man and named by another. Reverend, mineralogist and chemist William Gregor knew there was something special about the black magnetic sand he managed to isolate from the wet earth of the Menachan Valley in Cornwall, England. With a magnet and hydrochloric acid, he was able to produce an impure oxide of the new element, though it would never be known by the name he wanted it to have, “mechanite.”
Four years later, a Berlin chemist, Matthew Albert Klaproth, independently isolated titanium oxide from chunks of dark Hungarian rutile. His was the name that stuck, and rightly so. The Titans he conjured with this new name were tough, but they were also condemned by their own father to be held captive in the earth’s crust.
Titanium is the 9th most plentiful of all known elements. In terms of structural metals, it’s the 4th most abundant (following only aluminum, iron and magnesium). It is usually found in ileminite-rich mineral sands (from the Ilmen mountains in Russia) or laced in the rutile of the beach sands of Australia, India, Mexico. Workable deposits can also be readily located in the U.S., Canada, South Africa, Sierra Leone, Ukraine, Norway, Malaysia.
Titanium is highly resistant to corrosion — superior to metals like bronze, brass, copper nickel, both stainless and carbon steel. It’s strength-to-weight ratio is unmatched, having all the strength of steel but less than half its weight. These are amazing properties and indeed, titanium is often called a super metal. But its prevalence in the earth’s crust begs the question: why are products made from titanium so few and far between? The same properties that make titanium super strong, super light and super corrosion-resistant also happen to make it nearly impossible to work with.
FOOTBALL FIELDS AND JET PROPULSION
Titanium would not be isolated to 99.9% purity for well over 100 years after it was discovered. Of all places, the element was finally rendered pure on a football field. It makes sense when we consider that the football field was at the Renssalear Polytechnic Institute in Troy, New York, and located conveniently close to the labs.
The hero was a professor of electrical engineering and instead of a football, his game involved a metal bomb. It would become known as the Hunter Process — a dangerous, explosive method by which titanium chloride is mixed with metallic sodium in an air-tight metal chamber and heated to extremely high temperatures. It’s not entirely practical because it doesn’t yield large quantities of the metal, but it is still used today when titanium of ultra high purity is desired.
It wasn’t until William Justin Kroll developed the Kroll Process in 1948 that titanium would finally be completely unlocked from the earth and useable by man. In an elaborate chemical process full of painstaking breakthroughs, Kroll used the key players of titanium tetrachloride and magnesium. The Kroll Process is still widely used today, and it is what sent the metal into the engines of aircrafts with breakneck speed.
FEARLESS WARRIORS, POOR LAB PARTNERS
Isolating pure titanium is difficult but it is only one part of the grueling process that is conforming this metal to one’s will. It then needs to be bent, welded, machined or molded, all of which are extremely difficult due to the great tensile strength of the metal. The low thermal conductivity, high tensile strength and resistance to forces as corrosive as sea water make titanium one complicated workhorse of a metal.
Machining it is particularly difficult. The metal is almost stubborn, too strong to conform to another’s will. The low thermal conductivity often results in machines wearing down because the heat they’re using is dissipated by the low density metal. Titanium is so hard it’s likely to spring back and away from the blade that’s supposed to be cutting it, and cutting tools often need to be replaced. Large quantities of chemical fluid are needed to cool it down from its 1,600 degree melting point and turnings, fines and chips are instantaneous fire starters. While being worked with, it has a great tendency to fret and gall. Working with titanium requires devotion to science and process. Respect for the lustrous, authoritarian metal doesn’t hurt either — to say nothing of admiration and patience.
THE BODIES WE EXPLORE
Lucky for us all, the stubborn nature of the ore meets its match in the determination of engineers and scientists, and today titanium is used on nearly every front where its properties are needed, from leisure activities to space exploration.
We even use it to rebuild ourselves, to hinge together what breaks down over time in our bones and cartilage, small and large. Titanium screws together bones. From the load-bearing joint of the hip to the hardworking, ever-pumping valves of the heart, titanium is trusted to hold up to the chloride brines and organic acids that comprise the pH of the human body. It seems Adamantium — that indestructible, fictional element used by Dr. Cornelius to fortify the skeleton of Marvel’s Wolverine — may have found its inspiration in this amazingly biocompatible metal.
The low modulus — or stretch — of titanium, when paired with its superior corrosion resistance and strength-to-weight ratio also make it the first choice when it comes to exploring the unthinkable depths of the sea, where nameless creatures amble and deadly pressure reigns. The high-tech submersible, Alvin, is being newly built with a hull of three inch-thick titanium that will allow the vessel to reach depths of 4 miles deep, making all but 1% of the ocean floor accessible to oceanographers.
In the realms of flight and space exploration, titanium allows for maximum payload capability. With its low conductivity of heat and high melting point, it is the ideal way to allow moving parts like jet engine blades and gas turbines to function at the highest level of efficiency.
Though the costly development of this super metal might be delayed because of this Great Recession, we will be seeing titanium in more and more elements of daily life, from bicycles to outdoor supplies, to anything that needs to face the elements and hold its form without rusting or breaking apart. From Frank Gehry’s Bilbao Guggenheim Museum in Basque Country, Spain, to the ocean floor, to wedding bands and bicycles and tools for the backyard, this mythic metal is found in reaches far away, close and dark — whether we talk about the exploration of space or the beating of the human heart.
Leading image: Titanium deposits in sand in Eastern Cape, South Africa. Image by Niel Overey.
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