Superbainite

Structure of superbainite. Inset is a same-scale image of a carbon nanotube. [1]

Structure of superbainite. Inset is a same-scale image of a carbon nanotube. [1]

According to archaeologists, the Iron Age began in 1300 BC and lasted for around two millennia. Today, steels (alloys of iron and carbon) comprise 95% of global metal consumption and this trend shows no sign of declining.

Glancing at the media, however, one would be forgiven for assuming that steel is now a has-been. We are bombarded with stories of novel materials: carbon nanotubes, metallic glasses, graphene, carbon fibre, nickel superalloys. . . all of which are “stronger than steel”.

“Now we can construct space elevators!” claim the articles. “Let’s build a climbing frame to the moon! We’ll use this stuff to make everything!”

The observant among us, however, will note that most cars, trains and buildings still don’t feature superalloys, metallic glass or magic nanotubes. Neither are they invisible; nor do they fly; nor do they do any of the other things that journalists tend to ‘predict’.

Instead, steels somehow remain the best — and cheapest — materials for the job. Also, they are stronger than steel. This is because ‘steel’ is a vague construct used by sensationalists, with an unspecified strength guaranteed to be less than that of a novel material. Metallurgists rarely refer to ‘steel’, just as the Inuit have fifty words for snow, not one of which is ‘snow’.

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Japanese Swords are medieval nanotechnology

During Japanese sword making the steel is folded repeatedly. Each time the steel is folded the structure is refined.

The folding is a key process in sword making. Folding and striking the metal forges the surfaces back together. This process of folding, then forge welding, can be repeated as many as 16 times. The process removes impurities and helps even out the carbon content, and controls the scale of chemical segregation, and it is this which results in alternating layers of hard and ductile material.

So how can folding the steel result in a nanoscale structure?

When the steel is folded the number of layers obviously increases geometrically. 1 fold result in 2 layers, 2 folds results in 22 = 4 layers, 3 folds results in 23 = 8 layers. By the time we get to 15 or 16 layers we have 32768 layers or 65536 layers. After that the sword is forged out to have a width of around half a centimetre.

5 mm divided by 65536 = 76 nm.
(5e-3/65536=7.629e-8)

So each layer is 76 nm. So we can legitimately argue that Japanese Swords are bulk nano materials, with structure controlled on the ‘nano’ level, for metallurgists this is just routine stuff.

Edo period Forge Scene

Edo period Forge Scene

Of course Japanese swords are not true examples of nanotechnology, despite the validity of the maths the folding doesn’t really result in a controlled structure on the nanoscale due to the changes that occur during the welding process… I plan to talk more about that in a later post.

As you can see below, the laminations are typically visible on the millimetre scale.

Lamination on Japanese Sword

Lamination on Japanese Sword

nano day, unit conversion

I have noted the introduction of a new unit, the `nano day’, but what can it mean?

1 day = 3600 s × 24

1 n day = 86.4 μs

Mini vs. Nano, price comparison

How does the Tata Nano compare against the British equivalent the Mini which became an iconic car of the 1960s?

Original price of Mini was UK£ 497 when it was released in 1959. Competitors immediately bought one, and took it apart to see how it could be made so cheaply – they were confused, each mini should make a loss.

mini

Mini Car

Nano was priced at release on 17th of July 2009 at Rs 100,000, which is around UK£ 1360.

nano

Nano Car

So how do these prices compare?

Using this website
£497 from 1959 is equivalent to:
£8,656.34 using the retail price index.
or £21,038.85 using average earnings.

So from this we can see that Tata nano is around 6 times less than the mini was. It would probably more accurate to compare mini against 1959 average UK wage, and nano against 2009 average wage in India.

If average earnings in India are £3,500 (27 0000 Indian rupees) then this Tata nano price is about equivalent to the mini at release in 1959.

Tata Nano hits the roads soon.

BBC is reporting on the launch of the nano, and asking people is the Nano good for India?. Nay-sayers are complaining about the possible environmental impact of western style development in India. Yay-sayers support the effort to include those unable to purchase a car. Tata nano could have a positive impact upon air pollution in cities if it replaces older two-stroke two-wheelers, since I understand it should run on cleaner burning LPG fuel.

The release of the nano should add around 3% to the earnings of TATA group, which made losses in the last quarter after problems re-financing acquisitions in such as that of Jaguar and range rover from ford, due to the credit crunch. The manufacture of the nano has been delayed by cynical protests against building of the plant, and is currently being made in lower numbers in existing TATA motors plants, while a new facility has had to be relocated.

The world is still waiting to see if TATA can also develop an electric version.

Top Gear Show Nano

Top gear mentioned the Tata Nano in their news segment, seemingly just to make fun of this tiny car.

Tata Nano on Top gear news segment

Pikachu on left and Tata Nano on right
Pikachu on left and Tata Nano on right

After pointing out the similarity of the luxury version of the car to Pokemon Pikachu, saying they had kept the cost down by copying the design from the cartoon character, they said that the economy version is pulled by a mule.