2019 has been declared by UNESCO as the Year of the Periodic Table. To celebrate, we are releasing a series of blogs about our favourite elements and their importance to the chemical industry. Today’s blog focuses on titanium and its various uses in industries.
What is titanium?
Titanium is a silver- coloured transition metal, exhibiting low density, high strength and a strong resistance to corrosion from water and chlorine. Suitably, titanium delivers many uses to various industries with approximately 6.6 million tonnes produced annually.
Titanium Dioxide is the most popular usage of titanium, composed of approximately of 90%. It is a white powder with high opacity; its properties have been made for a broad range of applications in paints, plastic good, inks and papers. Titanium dioxide is manufactured through the chloride process or the sulphate process. The sulphate process is the more popular process making up 70% of the production within the EU.
Titanium’s characteristics - lightweight, strong and versatile, make titanium a valuable metal in the aerospace industry. In order for aircrafts to be safely airborne, the aerospace industry need parts which are both light and strong, and at the same time safe. Thus, titanium is seen as the most ideal match for these specifications.
Titanium implants have been used with success, becoming a promising material in dentistry. As a result of its features, including its physiological inertia, resistance to corrosion, and biocompatibility, titanium plays an important role in the dental market.
However, despite this, the technologies and systems used in the machining, casting and welding of titanium is slow and expensive. Despite the wide availability of these technologies and systems used in the process of creating dental prosthesis from titanium, it does depend on the technological advancements and the availability of resources, to create a more profitable and efficient manufacturing process.
Today, most rockets are fueled by hydrazine, a toxic and hazardous chemical comprised of nitrogen and hydrogen. Those who work with it must be kitted up in protective clothing. Even so, around 12,000t of hydrazine is released into the atmosphere every year by the aerospace industry
Now, researchers are in the process of developing a greener, safer rocket fuel based on metal organic frameworks (MOFs), a porous solid material made up of clusters of metal ions joined by an organic linker molecule. Hundreds of millions of connections join in a modular structure.
Robin Rogers, formerly at McGill University, US, has worked with the US Air Force on hypergolic liquids that will burn when placed in contact with oxidisers, to try get rid of hydrazine. He teamed up with Tomislav Friščić at McGill who has developed ways to react chemicals ‘mechanochemically’ – without the use of toxic solvents.
The pair were interested in a common class of MOFs called zeolitic imidazole frameworks, or ZIFs, which show high thermal stability and are usually not thought of as energetic materials.
They discussed the potential of using ZIFs with the imidazolate linkers containing trigger groups. These trigger groups allowed them to take advantage of the usually not accessible energetic content of these MOFs.
The resulting ZIF is safe and does not explode, and it does not ignite unless placed in contact with certain oxidising materials, such as nitric acid, in this case.
Authorities continue to use hydrazine because it could cost millions of dollars to requalify new rocket fuels, says Rogers. MOF fuel would not work in current rocket engines, so he and Friščić would like to get funding or collaborate with another company to build a small prototype engine that can use it.
The aerogel could be used to coat spacecrafts due to its resilience to certain conditions.
The aerogel comprises a network of tiny air pockets, with each pocket separated by two atomically thin layers of hexagonal boron nitride. It’s at least 99% space. To build the aerogel, Duan’s team used a graphene template coated with borazine, which forms crystalline boron nitride when heated. When the graphene template oxidises, this leaves a ‘double-pane’ boron nitride structure.
The basis of the newly developed aerogel is the 2D structure of graphene.
‘The key to the durability of our new ceramic aerogel is its unique architecture,’ says study co-author Xiangfeng Duan of the University of California, US.
‘The “double-pane” ceramic barrier makes it difficult for heat to transfer from one air bubble to another, or to spread through the material by traveling along the hexagonal boron nitride layers themselves, because that would require following long, circuitous routes.’
How does Aerogel technology work? Video: Outdoor Research
Unlike other ceramic aerogels, the material doesn’t become brittle under extreme conditions. The new aerogel withstood 500 cycles of rapid heating and cooling from -198°C to 900°C, as well as 1400°C for one week. A piece of the insulator shielded a flower held over a 500°C flame.
From monitoring our heart rate and generating renewable energy to keeping astronauts safe in space, a number of novel applications for carbon nanotubes have emerged in recent months.
Academic and industrial interest around carbon nanotubes (CNTs) continues to increase, owing to their exceptional strength, stiffness and electronic properties.
Over the years, this interest has mainly focused on creating products that are both stronger and lighter, for example, in the sporting goods sector, but recently many ‘quirkier’ applications are beginning to appear.
Carbon nanotubes are already used in sporting goods such as tennis racquets. Image: Steven Pisano/Flickr
At Embry-Riddle Aeronautical University in Prescott, Arizona, for example, researchers are currently working with NASA on new types of nano sensors to keep astronauts safer in space.
The Embry-Riddle team – along with colleagues at LUNA Innovations, a fibre-optics sensing company based in Virginia, US – have focused on developing and refining smart material sensors that can be used to detect stress or damage in critical structures using a particular class of CNT called ‘buckypaper’.
The next step in nanotechnology | George Tulevski. Video: TED
With buckypaper, layers of nanotubes can be loosely bonded to form a paper-like thin sheet, effectively creating a layer of thousands of tiny sensors. These sensor sheets could improve the safety of future space travel via NASA’s inflatable space habitats’ – pressurised structures capable of supporting life in outer space – by detecting potentially damaging micrometeroroids and orbital debris (MMOD).
CNTs coated on a large flexible membrane on an inflatable habitat, for instance, could accurately monitor strain and pinpoint impact from nearby MMODs.