dan shechtman

Dan Shechtman’s discovery of quasicrystals brought about a paradigm change in chemistry, physics, materials science, and other areas of science and engineering. Although superficially it could be looked at as a serendipitous event, Shechtman’s curiosity and drive played equal parts with serendipity in this discovery. 

Shechtman was a lonely discoverer, again, seemingly detached from the main stream of generalized crystallography for which his contribution was a milestone.

The formula of the invention

an alloy based on quasicrystals of the al-cu-fe system

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Al (aluminum)

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Сu (cuprum)

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Fe (ferrum)

Al-Cu-Fe

Quasicrystalline powder

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Friction coefficient on steel

0,2

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Density

4 g / cm3

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Thermal conductivity

2 W / (m • K)

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Dispersion of the base powder

1-63 microns (can be changed at the request of the customer)

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Hardness

800-1000 HV

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Resistivity (at T br)

4,5 mOhm ∙ cm

Marketing

nobel prize

Shechtman was awarded the Nobel Prize in Chemistry in 2011 for his work on quasicrystals. “His discovery of quasicrystals revealed a new principle for packing of atoms and molecules,” stated the Nobel Committee and pointed that “this led to a paradigm shift within chemistry.”
In 2014, Post of Israel issued a stamp dedicated to quasicrystals
and the 2011 Nobel Prize.

History

Quasicrystal

1945

On July 16, 1945, in Alamogordo, NM, the Trinity nuclear bomb test produced icosahedral quasicrystals. They went unnoticed at the time of the test but were later identified in samples of red Trinitite, a glass-like substance formed from fused sand and copper transmission lines. Identified in 2021, they are the oldest known anthropogenic quasicrystals.

1961

Tab Address
Hao Wang asked whether determining if a set of tiles admits a tiling of the plane is an algorithmically unsolvable problem or not. He conjectured that it is solvable, relying on the hypothesis that every set of tiles that can tile the plane can do it periodically (hence, it would suffice to try to tile bigger and bigger patterns until obtaining one that tiles periodically). Nevertheless, two years later, his student Robert Berger constructed a set of some 20,000 square tiles (now called “Wang tiles”) that can tile the plane but not in a periodic fashion. As further aperiodic sets of tiles were discovered, sets with fewer and fewer shapes were found. In 1976 Roger Penrose discovered a set of just two tiles, now referred to as Penrose tiles, that produced only non-periodic tilings of the plane. These tilings displayed instances of fivefold symmetry. One year later Alan Mackay showed experimentally that the diffraction pattern from the Penrose tiling had a two-dimensional Fourier transform consisting of sharp ‘delta’ peaks arranged in a fivefold symmetric pattern. Around the same time, Robert Ammann created a set of aperiodic tiles that produced eightfold symmetry.

1972

Tab Address
In 1972 de Wolf and van Aalst reported that the diffraction pattern produced by a crystal of sodium carbonate cannot be labeled with three indices but needed one more, which implied that the underlying structure had four dimensions in reciprocal space. Other puzzling cases have been reported, but until the concept of quasicrystal came to be established, they were explained away or denied

1982

Tab Address

Shechtman first observed ten-fold electron diffraction patterns in 1982, while conducting a routine study of an aluminium-manganese alloy, Al6Mn, at the US National Bureau of Standards (later NIST). Shechtman related his observation to Ilan Blech, who responded that such diffractions had been seen before.Around that time, Shechtman also related his finding to John W. Cahn of the NIST, who did not offer any explanation and challenged him to solve the observation. Shechtman quoted Cahn as saying: “Danny, this material is telling us something, and I challenge you to find out what it is”.

1984

Tab Address

Shechtman accepted Blech’s discovery of a new type of material and chose to publish his observation in a paper entitled “The Microstructure of Rapidly Solidified Al6Mn”, which was written around June 1984 and published in a 1985 edition of Metallurgical Transactions A. Meanwhile, on seeing the draft of the paper, John Cahn suggested that Shechtman’s experimental results merit a fast publication in a more appropriate scientific journal. Shechtman agreed and, in hindsight, called this fast publication “a winning move”. This paper, published in the Physical Review Letters, repeated Shechtman’s observation and used the same illustrations as the original paper.

1985

Tab Address

Also in 1985, Ishimasa et al. reported twelvefold symmetry in Ni-Cr particles. Soon, eightfold diffraction patterns were recorded in V-Ni-Si and Cr-Ni-Si alloys. Over the years, hundreds of quasicrystals with various compositions and different symmetries have been discovered. The first quasicrystalline materials were thermodynamically unstable—when heated, they formed regular crystals. However, in 1987, the first of many stable quasicrystals were discovered, making it possible to produce large samples for study and applications. 

1992

Tab Address

In 1992, the International Union of Crystallography altered its definition of a crystal, reducing it to the ability to produce a clear-cut diffraction pattern and acknowledging the possibility of the ordering to be either periodic or aperiodic. 

2001

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In 2001, Paul Steinhardt of Princeton University hypothesized that quasicrystals could exist in nature and developed a method of recognition, inviting all the mineralogical collections of the world to identify any badly cataloged crystals. In 2007 Steinhardt received a reply by Luca Bindi, who found a quasicrystalline specimen from Khatyrka in the University of Florence Mineralogical Collection. The crystal samples were sent to Princeton University for other tests, and in late 2009, Steinhardt confirmed its quasicrystalline character. This quasicrystal, with a composition of Al63Cu24Fe13, was named icosahedrite and it was approved by the International Mineralogical Association in 2010. Analysis indicates it may be meteoritic in origin, possibly delivered from a carbonaceous chondrite asteroid. In 2011, Bindi, Steinhardt, and a team of specialists found more icosahedrite samples from Khatyrka. A further study of Khatyrka meteorites revealed micron-sized grains of another natural quasicrystal, which has a ten-fold symmetry and a chemical formula of Al71Ni24Fe5.. This quasicrystal is stable in a narrow temperature range, from 1120 to 1200 K at ambient pressure, which suggests that natural quasicrystals are formed by rapid quenching of a meteorite heated during an impact-induced shock.

2011

Tab Address

Shechtman was awarded the Nobel Prize in Chemistry in 2011 for his work on quasicrystals. “His discovery of quasicrystals revealed a new principle for packing of atoms and molecules,” stated the Nobel Committee and pointed that “this led to a paradigm shift within chemistry.” In 2014, Post of Israel issued a stamp dedicated to quasicrystals and the 2011 Nobel Prize. 

2018

Tab Address

In 2018, chemists from Brown University announced the successful creation of a self-constructing lattice structure based on a strangely shaped quantum dot. While single-component quasicrystal lattices have been previously predicted mathematically and in computer simulations, they had not been demonstrated prior to this.

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