Dan Shechtman was born January 24th, 1941 and is from Tel Aviv, which at the time was part of Palestine and today is part of Israel. Shechtman was very interested in science from a young age and after graduating high school he decided he wanted to become an engineer. After high school, he completed two years of military service, which is required for all citizens of Israel. During this time, Shechtman began going to school at Technion Israel Institute of Technology. While attending Technion, he studied mechanical engineering and planned on getting a job within that field. However after finishing the schooling required for mechanical engineering, the job options were very limited so Shechtman decided to continue going to school. Eventually, he found a good job in the field, however, by this point, he had become uninterested in engineering and began doing work with a man named David Brandon.
Brandon essentially is responsible for the creation of the transmission electron microscope. From this point on, Shechtman extensively studied transmission electron microscopy. During a sabbatical, he studied in the United States where he made his award-winning discovery of quasicrystals at the National Institute of Standards and Technology(NIST). While on his sabbatical at the NIST, Dan Shechtman studied closely with David Brandon who created the transmission electron microscope(TEM). Brandon couldn’t speak english, so Shechtman had to pay close attention to the microscope and how to use it. Due to the creation of this electron microscope, Shechtman managed to be able to thoroughly study transmission electron microscopy. The TEM is basically a microscope that uses electrons similar to how a light microscope would use light. It allows very detailed images to be seen within cells or other microscopic objects.
The way it works is it releases electrons from the top of the apparatus. In order for the electrons to be shifted into a very thin stream, they are hit with electromagnetic lenses. The electrons are then lead into the sample being studied through the microscope, which allows a detailed image of whatever microscopic object is being studied(“The Transmission Electron…”).
It was through this microscope that the discovery of quasicrystals was made by Dan Shechtman. One morning, Shechtman peered through the microscope at a substance that he formulated and found that the cells were in a non-repeating pattern. This opposed many views regarding the study of crystallography. In the book, Quasicrystals: A Primer, it says, “Quasiperiodic structures, or quasicrystals for short, are non-crystalline materials with perfect long-range order, but with no three-dimensional periodicity ingredient whatsoever, not even the underlying lattice of the incommensurate structures”(Janot, pg. 1).
In other words, quasicrystals are solids that contain atoms which are arranged in a format that does not repeat itself, though it may look as if it repeats itself. The word is derived from the Latin root Quasi, which means: Apparently, but not really. Shechtman discovered quasicrystals through an experiment where he melted an alloy that contained manganese and aluminum. Then, he solidified it using a cold spinning wheel, which cooled it rapidly. The steps taken to rapidly cool the mixture are called melt spinning. The newly solidified substance was then placed under the electron microscope(Michael Widom, “Quasicrystal”). When the stream of electrons passed through the substance, Shechtman was shocked to find that the diffraction patterns were not as expected. In an interview, Shechtman describes what he was thinking as he looks through the microscope.
He describes, “Immediately my thought was that this is a twin structure I spent all afternoon looking for the twins with every method that was available, but couldn’t find it. So I knew it was something. But what was it? I knew that it was not a twinned structure”(Rachel Gaal, “APS News”). Twinning is basically when two crystalline substances join together and share a plane of symmetry. Twinning generally occurs when a crystal is developing and some type of pressure is put upon it. It leads the crystal to form one or more crystals onto it(“Twinning in Crystals”).
However, Shechtman eventually realized that this was not the case. For a period of time after the unusual discovery, some scientists were unaccepting of his findings, due the fact that it defied previously known information. The atoms seen through Shechtman’s electron microscope were arranged in a non-repeating pattern that had never been observed before. Before this discovery, it was always thought that rotational symmetries could only be 2, 3, 4 and 6-fold. This classical idea is known as the crystallographic restriction theorem. Because of this, many were shocked to find that Shechtman had observed up to a ten-fold symmetry (Julie Geng, “Academic Journal”). Crystallography is basically the scientific study of crystals. Crystals are solids that have symmetrical planes and they are considered to be homogeneous.
The Laws of Crystallography are stated as follows: “Law of constancy of interfacial angles, law of rational indices and the law of constancy of symmetry”(“Laws of Crystallography”). The first law listed, essentially states that angles within a crystal will always be the same regardless of the size and shape of the crystal. The second law listed, describes how the intercepts found in different places of the crystal are always the same. The final law, which states that crystals must be symmetrical, applies most relatively with the idea of quasicrystals. For crystals, this law means that they must have symmetrical planes, axes, and centres(“Laws of Crystallography”). However, this is not the case for quasicrystals since they have a non repeating pattern and therefore do not require symmetry.
Before the discovery of quasicrystals, there were two main classifications of solid matter substances: Crystalline and amorphous (Rajesh Prasad, “Basic Crystallography”). Crystalline substances are solids that have atoms which show a repeating pattern. Amorphous substances contain atoms that don’t have any specific order (“Amorphous solids”).
Quasicrystals can now be considered another branch of solid matter, alongside crystalline and amorphous. The discovery of quasicrystals has majorly changed the study of Crystallography. This field had already been thoroughly studied and most believed that there was not much more to learn within the field. When quasicrystals were discovered many people argued against it. For example, scientist Linus Pauling was a major skeptic of Shechtman’s findings. Pauling received a Nobel Prize for chemistry in 1954. He is considered one of the top scientists of his time, however, he was incorrect in his skepticisms over Shechtman’s discovery(“Linus Pauling..
.”). Eventually, quasicrystals were accepted by all.
Jean Marie Dubois, a French scientist used quasicrystals to effectively be used as a coating for frying pans and other cooking appliances. The decision to use quasicrystals was made after he discovered that using another type of metal coating would be less effective because they’re amorphous. If an amorphous metal comes into contact with high temperatures, such as those on a stove, they will be easily destroyed.
In addition to this, using a quasicrystal coating, as opposed to a regular metal coating, will prevent food from sticking to the pan. Dubois created a quasicrystal alloy for frying pans that was specifically made to “Have low coefficients of friction, high hardness, and low surface energy” (Mitch Jacoby, “Quasicrystals: A New… “).
Dubois did experiments by cooking food over a frying pan coated with his formulated quasicrystal alloy coating. The results came out positive, proving that quasicrystals make a great surface for cooking. One major characteristic of quasicrystals is that they are poor conductors of heat. At first, this characteristic may make it seem is though quasicrystals would make a bad source for cooking since it is a poor conductor of heat. However, this characteristic is actually what makes it most fit to be used for cooking. Being a poor heat conductor allows it to spread the heat evenly and steadily along the pan surface. Good heat conductors would not make good cooking surfaces because it would heat up too quickly and unevenly causing food to easily burn and not cook through properly(Mitch Jacoby, “Quasicrystals: A New.
Another way quasicrystals have been applied to the real world is to enhance the strength of steel. An engineering company from Sweden named Sandvik uses quasicrystals for a product they created called Sandvik Nanoflex. This product is a steel alloy that is very strong and doesn’t wear down easily.
Overall, the characteristics of quasicrystals allow it to be used in steel which in turn can be used for a variety of different things. The Sandvik Nanoflex is what the call the steel that contains quasicrystals. The Nanoflex steel is used for many different medical supplies. One specific thing that makes quasicrystals fit for medical equipment is that they are harder than most metals. This makes them able to do things more effectively such as cut through human flesh. It is used in things such as needles, syringes, and other things of that sort. Before quasicrystals were used for these types of medical equipment, certain types of surgeries were not possible.
For example, a type of spinal surgery is now possible because the supplies used for the surgery that contain the quasicrystals make them more durable. Therefore, the surgery can successfully be performed (“Quasicrystals Strengthen…”). A very recent example of quasicrystals in the real world was when a quasicrystal meteorite was found. It was discovered in Khatyrka which is in a region of Russia in December of 2016. The meteorite was small and they discovered that they had quasicrystal structure by comparing it to the only two other natural quasicrystals ever found.
They used a transmission electron microscope to study and determine the type of meteorite. Using the microscope they found that the meteorite contained iron, aluminum, and copper. It is possible the meteorite formed quasicrystals while in space. This is a valid hypothesis because all three of the naturally found quasicrystals were attached to meteorites. In my opinion, I feel that Dan Shechtman’s work was a very important discovery. First of all, it is always very important for science to continually be studied and improved because there is always something new to learn.
It is necessary that we understand the natural world around us and the only way to do that is to always be looking for new or changing information. This is exactly what Shechtman did. The field of crystallography was already thoroughly studied and most believed the information to be firm and unmoving. However, due to Shechtman, a huge discovery was made that changed that. Many were skeptical but ultimately his discovery proved to be correct and added a lot to the study of chemistry. It majorly altered the way people viewed crystallography because now there is a whole new category for solid matter.
Before quasicrystals were found, solid matter had two categories: Crystals and Amorphous. However, now there is an additional branch: Quasicrystals. Furthermore, I feel that Shechtman’s discovery of quasicrystals is important because it enhanced medical equipment. Many items used in hospitals and doctors offices now put to use quasicrystals which make more durable steel.
The use of quasicrystals in medical supplies also allows certain surgeries to be done more successfully which is always something that needs to be improved.