Titanium: The Wonder Metal That Never Quite Was

Podcast Transcript

Titanium is the ninth most abundant element in the Earth’s crust.

However, titanium is not even remotely close to the ninth most common element in industrial or commercial use.

In fact, despite being so abundant, we didn’t even know titanium existed until the late 18th century, and we couldn’t figure out how to actually practically use it until the 1960s.

It is a remarkable metal with amazing properties that is still incredibly hard to work with.

Learn more about titanium, the amazing yet difficult metal, on this episode of Everything Everywhere Daily.

Titanium is the 22nd element on the periodic table. It is a silvery metal that looks very similar to steel in its pure elemental state. It has a very good strength-to-weight ratio and is highly resistant to corrosion. It is a relatively poor electrical conductor compared to other metals, and it doesn’t expand or contract much with temperature changes.

It is also non-toxic and is considered to be biocompatible, which, as we’ll see in a bit, has many useful properties.

It is the 9th most abundant element in the Earth’s crust and the 4th most abundant metal.

The short story about titanium is that it is a metal with really attractive properties and is very abundant.

You’d think that such an attractive metal would have been used throughout history. However, you’d be wrong.

No one had a clue that titanium even existed for most of human history. The reason why titanium remained hidden had to do with its chemical proclivity to bond with pretty much anything.

This is pretty much the opposite of how gold reacts, which is why gold is almost always found in its natural metallic state. If you remember back to the episode on aluminum, it is very similar to titanium in that pure metallic aluminum almost never exists in nature.

The difference is that whereas there were very few examples of pure aluminum, there are no known examples of pure titanium.

Humans in history were aware of and did use compounds that contained titanium, but at the time, they had no clue what elements were or that such compounds were made up of more elementary things.

The person who is credited with the discovery of titanium is British clergyman and mineralogist William Gregor. In 1791 he was studying a sample of sand from Cornwall when he identified two oxide metals in the sand. One was iron oxide, and the other was a white metallic oxide that he couldn’t identify.

He eventually concluded that this oxide must contain a new element. He published his findings and named the new substance “manaccanite.”

Four years later, the German chemist Martin Heinrich Klaproth came across the same oxide that Gregor had discovered. He, too, recognized that the material must be a new element, which he named Titanium after the titans of Greek mythology.

Later, Klaproth heard of Gregor’s discovery and obtained a sample of the sand Gregor studied from Cornwall and found it was also Titanium.

Klaproth credited Gregor with the discovery of Titanium, but it was his name for the element that stuck.

Both Klaproth and Gregor had identified that there had to be a new element in the compounds they studied, but neither of them was actually able to isolate the element. Neither of them ever saw actual pure titanium.

For over 100 years, chemists continued to study titanium, but no one was able to actually create a sample of pure titanium. They could get it to bind with other elements, but they couldn’t isolate it.

There were certain things they were able to learn about titanium, but they weren’t able to determine its most important properties without pure titanium.

They were, however, getting close. By the 1880s, Swedish chemists were able to make 94% pure titanium.

It wasn’t until 1910 that Matthew Hunter, a scientist at General Electric and the Rensselaer Polytechnic Institute, used a variation of the Swedish process to finally produce metallic titanium. He was searching for new potential lightbulb filaments.

His process, known as the Hunter Process, involved heating titanium tetrachloride with sodium at temperatures as high as 800 °C or 1,500 °F at very high pressures.

This allowed for the creation of titanium with purity levels over 99.9%.

While this was a breakthrough, and it finally allowed researchers to study titanium as metal in its pure form, it really had no practical application. The process was too difficult, and it could only produce very small amounts.

The idea of using titanium for something like a golf club was still a long way away.

The breakthrough in the ability to create titanium for industrial use occurred in 1930, less than 100 years ago.

A scientist from Luxembourg named William Kroll was running experiments with titanium. Over a period of years, he developed a process of reacting titanium tetrachloride with magnesium in a vacuum.

Known as the Kroll process, it creates an end product that is called a titanium sponge. It is called a titanium sponge because it is very porous and looks like a sponge, not because it is actually absorbent.

A titanium sponge is mostly pure titanium with some other impurities, mostly magnesium, that need to be further refined. However, it is a starting material and the biggest part of making titanium

By 1938, Kroll had been able to make over 50 pounds of pure titanium metal and used to to make simple metal objects such as wires and titanium plates.

In the 1940s, the US Bureau of Mines began to investigate ways of producing titanium and determined that the Kroll Process was the best means of commercial titanium products, and while it has been improved over the years, the basic Kroll Process is still used today.

During the second world war, the Bureau of Mines was making 100 pounds of titanium per week.

100 pounds a week is still not a lot of metal. You couldn’t really build anything out of it, but it vastly expanded the ability to conduct engineering experiments with the metal. Samples were sent to laboratories, and researchers discovered many of the things I mentioned at the start of this episode.

It was as strong as stainless steel but weighed 40% less. It was resistant to corrosion, and it performed well at high temperatures.

People began envisioning airplanes, ships, and vehicles made out of titanium, and some thought it could replace both aluminum and steel in industrial production.

The press called titanium the “wonder metal” and the “miracle metal.”

In the early 1950s, a least two dozen companies in just the United States announced plans to create titanium. It was the tech boom of that era.

However, there was a problem.

Titanium production never was able to match expectations. Only 75 tons of titanium was produced in 1951, despite a demand for over 30,000 tons.

Besides the big problem of simply making titanium, now that they had some actual metal to work with, they found another very significant problem.

Titanium didn’t behave like other metals. Everyone had just assumed that they could repurpose the same machines that were used for stainless steel production. Metal is metal, right?

Well, it turned out that working with pure titanium was nothing like working with steel. You couldn’t forge, stamp, roll, or grind titanium like you could with other metals.

For example, when drilling titanium, if you drilled it at speeds used on normal metals, the temperatures would rise dramatically, damaging the drill bit. You had to drill slower, which took much more time.

This made making anything extremely difficult. The first attempt at trying to make a panel for an aircraft resulted in a sheet of metal that could be ripped like a piece of paper.

All of the dreams about the miracle metal revolutionizing the world were falling apart.

The failure of pure titanium led to trying to find titanium alloys that would be easier to work with. The eventual alloy which was discovered and is still popular today is 90% titanium, 6% aluminum, and 4% vanadium.

Perhaps the biggest event in the history of titanium was the development of the high-speed reconnaissance spy plane known as the Lockheed A-12.

The A-12 was the predecessor to the SR-71 Blackbird, which was the subject of a previous episode. The A-12 was to be the fastest aircraft in the world, something that could outrun any enemy missiles.

As such, it would need to be very lightweight and have a skin that could handle the high temperatures that would be created due to friction.

Titanium seemed to be the perfect metal for the job.

This was the biggest titanium project ever by a wide margin. Prior to the A-12, titanium was primarily used for small parts in jet engines. The A-12 was to be 93% titanium by gross weight.

Construction of the A-12 required the development of new techniques for using titanium…. and the discovery of even more problems. For example, they discovered that water with chlorine in it caused welds to weaken. Titanium bolts would have their heads pop off if they were tightened with cadmium-coated wrenches.

Every time they solved one problem, it seemed they created another.

A full 95% of the first 6000 titanium components created for the A-12 couldn’t be used.

Eventually, however, they did solve many problems of working with titanium.

The creation of the A-12, in a very literal sense, spawned the creation of the titanium industry. It was from the production of the A-12 that a base of knowledge was created in milling and working with titanium.

Another major discovery regarding titanium was made in 1952. In Sweden, an experiment with rabbits accidentally found that bone would bind with titanium metal.

This process, dubbed osseointegration, had never been observed before. It had previously been assumed that the body would reject any foreign substance.

Further experiments found that the body didn’t reject titanium and that there were no negative consequences.

Today, titanium is used for screws and plates to mend broken bones, as well as in dental implants.

Throughout the Cold War, titanium was classified as a strategic mineral, so its use was limited. The US Department of Defense actually created a strategic stockpile of titanium sponges. These were to be used in projects which were deemed to be spongeworthy.

When the Cold War ended, titanium was reclassified, and in 2000, the titanium sponge reserve was sold.

The end of the Cold War and the reclassification of titanium away from being a strategic material change the market for titanium.

Whereas titanium was only used for important high-value items like aircraft parts, titanium was now available to be used for other purposes, such as golf clubs, tennis rackets, and bicycle frames.

The biggest use of titanium today, by far, is titanium dioxide.

Titanium dioxide is a very white pigment. A full 95% of all titanium that is mined will end up as titanium dioxide.

Titanium dioxide is used in paint, plastics, paper, cosmetics, and even in toothpaste. It is extremely white, which means it can reflect light and heat well. The exterior of the Saturn V rockets used in the Apollo program was painted with titanium dioxide.

Titanium is a very odd element. It is very common in nature, and it has amazing properties, but it never fulfilled its promise as a “wonder metal”. It never became as widespread as a similar metal that gained popularity in the 20th century, aluminum.

One big reason titanium isn’t used more than it is, is that it is just hard to work with.

More important than that is the fact that titanium still remains relatively difficult to make as we have never developed a process substantially better than the Kroll Process. If someone could develop such a system, it would have the potential to usher in a true titanium revolution and finally allow this wonder metal to fulfill its promise.