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TITANIUM

History | Features | Nanotecnology | In art | Tibow jewelry | Damascus

A short history of titanium

A pictoresque sight on the Helford river. William Gregor found the titanium-containing rocks along its banks.

Titanium was separately discovered by two mineralogists:

  • William Gregor, British, in 1791 isolated an unknown metal in the ilmenite rocks of Cornwall, and called it "menacanite", by the name of Manaccan village, where he had collected the rocks.
  • Few mounths later, the German Martin Heinrich Klaproth came upon the same metal in rutile minerals (rutile is titanium dioxide, indeed). He proposed to call the new metal "titanium", by the name of those ancient Greek Gods, cause of its extraordinary features of strenght, resistance and lightness.

William Gregor, 1761 - 1817.

Martin Heinrich Klaproth, 1743 - 1817.

Gregor accepted the new name "titanium", and in the following years he discovered the metal in samples of Tibetan corundum and Cornwall's turmaline too.
Klaproth, on his hand, proceeded the research, and became the first scientist to isolate the uranium and the zrconium.

The first method able to produce pure titanium in significant quantity was developed by the New Zealander Matthew Albert Hunter in 1910 but his way, based on explosive reactions with sodium and chlorides, was very dangerous; moreover it was not providing titanium enough to produce a profitable market.

Titanium remained therefore a laboratory element until 1946, when the Luxembourgian Guillaume Justin Kroll at least developed an efficient way to extract titanium; this method was less dangerous thanks to reactions with the magnesium and good to produce industrial amounts of titanium.

Matthew Albert Hunter, 1878-1961.

Guillaume Justin Kroll, 1889 - 1973.

Afterward, electrolytic systems were identified to extract titanium by the minerals containing it; the most promising one is the Armstrong method. This procedure is more efficient, but does not produce a titanium pure enough for many applications of the titanium, so the Kroll's method is still the most used (detailed study on titanium production).

Although titanium revealed to be a very common element in the Earth's (and Moon's too) rocks, its extraction is still now very expensive; therefore titanium price is about six times higher than that of the steel.

The first Company to undertake the industrial production of titanium through the Kroll's method was the American Du Pont, in 1948. Since then, cause of its characteristics, titanium and its alloys have been gaining more and more importance in technology and in modern life: from the aerospatial field to chemistry, from the medicine to the art world, titanium become the leading metal of innovation.

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Characteristics of titanium.

Titanium is a very special metal, abundant in earth crust, where we find it at the fourth place between the metals, after alluminium, iron and magnesium.

Titanium belongs to the chemical group known as "transition metals ", with iron, zirconium, manganese and 36 more metals.

The transition metals in the Periodic Table of the Elements. Lanthanum and actinium belong also to the rare-earth group.

These elements share the strong mechanical resistance and the possibility to produce colourful oxidations and salts, but titanium stands out for its qualities of lightness, toughness and resistance to corrosion.

Titanium stands from the other metals also in the field of colourants, because some of its salts and oxides are particularly brilliant and stable.
Therefore about 90% of the extracted titanium is used by the man to produce colourants. Between these, we must recall the titanium dioxide, better known as "titanium white", which has already substituted the traditional "white lead" in the industry of colours and of their applications.

The high biological tolerability of titanium and of its compounds assigned to it a dominant place in dyeing, whether in the textile industry or in the cosmetics one or in food.

Here a vintage documentary on the dawning of titanium pigments technology.

The remaining 10% of extracted titanium is exploited as metal and alloys, taking advantage of its mechanical and chemical endurance.

Only thanks to titanium aeronautics could become aerospace, and not only cause of the ligthness of the material.
In the engineering of vectors and spacecrafts was overall important the capability of titanium to withstand high temperatures and powerful chemical aggressions by the propellants.

The Apollo Spacecraft, which could reach the Moon thanks to titanium characteristics.

The complete resistance of titanium to corrosion, even by sea water and galvanic currents, offers to titanium and to its alloys the application in wide fields, like shipbuilding and turbines engineering.

Due to its highest biocompatibility, in the field of medicine and surgery titanium allowed the realization of the well-known internal prostheses, lessening the rejection danger.
Less known, remaining in hygienics, is the discovery that titanium dioxide nanoparticles can produce self-sterilizing surfaces under the effect of Sun rays.

Being chemical aggression-proof and not easy to bind with other elements makes titanium precious to build laboratory equipment and catalysts.

Its mechanical strenght and its aesthetic qualities inserted titanium between the materials adopted by modern architects, industrial designers, watchmakers and jewellers.

In these two last branches, again, the titanium biocompatibility is relevant, as it offers hypoallergenic qualities only comparable to those of platinum.
Unlike the high-priced and very heavy platinum, titanium shows much lower price, better mechanical resistance, lightness (specific weight of platinum is 21.4, while titanium one is 4.87) plus the possibility to be coloured in many hues, including those of gold.

By the chemical point of view, titanium should well worth the title of "noble metal", as its resistance to acids, alkali and other aggressive compounds is only paired by platinum. For not explained reasons, it is not officially included in that list, while much less proper metals like copper or mercury sometimes are.

The China National Theatre building in Peking, made out of titanium and titanium-glass.

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Titanium, the father of nanotechnology

Titanium is also the main protagonist of the new scientific progress developments known as nanotechnologies.
Thanks to the minimum thickness of its oxide, in fact, man could access that working range expressed in nanometres, that is billionths of a metre.

Lately, titanium dioxide nano-particles have been discovered to be strong agents to neutralize the pollutants. When exposed to Sun light, these molecules produce a catalytic process able to transform the main pollutants (nitrous dioxide, benzene, carbon monoxide, sulphuric compounds, fine dusts and others) into small amounts of harmless mineral salts already present in the Nature. The first employment of this titanium characteristic was in filters for water purifying devices, but nowadays this action extends to the air purification too.

Main Universities deepened the study of the titanium photocatalytic capabilities and International Companies (between them the Italian Italcementi) are producing titanium dioxide based paints and cements which, tested in city areas, demonstrated to reduce the most dangerous pollutants by percentages between 30 and 70%, depending from the kind of substance and the weather.

Wierer Company manufactures titanium dioxide treated shingles, which have shown to reduce the concentration of polluting sediments up to 90%, pursuant to the tests made by the Fraunhofer-Gesellschaft, an important applied research European Institute.

The Italian Company Suncover, as well, commercializes a titanium dioxide based spray to coat its curtains and mosquito nets, to transform them in powerful domestic smog filters.

To deepen the purifying capability of titanium, please see:
http://www.tecnologiaericerca.com

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Titanium in Art

As it is known, just two metals are in themselves coloured, gold and copper; the about sixty others show shades between white and gray. Nevertheless sometimes their surfaces look coloured, maybe cause of the light interference on coats or very thin superficial layers. Let's think to the soap bubbles iridescence or to oil spots on the tarmac (Pietro Pedeferri).

If the already mentioned hypoallergenic qualities of titanium have shown to be precious for wearable objects, while lightness and resistance brought this metal to the attention of the top modern architects, the chromatic possibilities of titanium made of it an interesting material for painters too.

The engineer Pietro Pedeferri, director of the Department for Applied Chemistry-Physics in the Politecnico di Milano was the first to explore these titanium properties.

Pietro Pedeferri, 1938 - 2008 (photo courtesy of http://www.vaol.it/).

Pietro Pedeferri, "Apparenza di campo", titaniocromia (photo courtesy of http://www.valtellinarte.it/).

Pedeferri was between the first scientists to apply to the study of titanium dioxide nanoparticles, since 1967 while still a student.

From the beginning Pedeferri addressed his research on two rails: on one side the technological research, which brought him to estabilish the current anti-corrosion protocols for concrete scaffolding, on the other the study and experimentation of the pictorial possibilities offered by the titanium.
Pietro Pedeferri wrote:

it is noticeable that titanium, while thirty years ago carried us to the Moon, the satellite was reached with a titanium capsule, indeed, nowadays is pushing us into the world of thin layers and therefore of the nano-materials. This regard engineering.
But it is undeniable that this material, with its colours, its \appearances", its light is of high interest also for the world of architecture and that of design in all their conjugations, from furniture to products, to visual communication to fashion: so, the world of the "made in Italy".
However, as Consonni writes, the availability of an extraordinary material, allowing to obtain "precious colours and shapes created not reproducing Nature, but stimulating her to produce them in all their peremptory elegance, can only be seen as a provocation to its artistic use"
(da http://www.enco-journal.com/).

Pedeferri's science started therefore to produce artworks, from the first little plates collected as pages in the small limited editions books by the publisher Casiraghy or enchased like jewels by the goldsmith James Rivire, up to the wide plates of Pedeferri's last years.

This art, that pedeferri called "titaniocromia" has its great precursor in another Italian, Leopoldo Nobili, that in 1828 presented to the french Academy his first experiments of metal coloured by him without the use of enamels or varnishes, just creating oxidation surfaces able to produce light-interference colours.
Nobili named his art "metallocromia" and stated that: the art was already at the point to gain its place between the others.

The astatic galvanometer invented by Nobili. (photo courtesy of http://www.liceoariosto.it/).

Leopoldo Nobili, 1784 - 1835 (photo courtesy of Wikipedia).

Nobili defined his colorations "electrochemical appearances" and succeeded to create a range of 44 different hues, even not useing titanium, that was a too recent discovery. It has been verified that the disposition and the generation of these tints mirror the order of the newtonian rings, underlining this human craft as perfectly harmonic with natural laws.

Reviewing a book from Pedeferri, Maria Corti wrote:

The colours assumed by titanium under electrochemical oxidation and light reflections, join the instant to eternity, because they resist to atmpospheric agents and are secured beyond time, as is forever, like the artwork, call it Iliad or Odissey. ... those called "electrochemical appearances" by Nobili ... amazing to say, but we are facing an order which belongs to Nature: just think o the rainbow, to the colouring of the clouds at dawn or sunset. The order of colours in the chromatic scale is a natural order, whence a casual juxtaposition does not exist. It is therefore important to realize that the signs, might they be colours or sounds (musical or verbal) produce in nature effects of harmony and melody ... (from http://ricerca.repubblica.it).

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Titanium jewelry by TiBow Design

TiBow Design, anodized and etched titanium necklace pendent.

TiBow Design, anodized titanium necklace pendent.

The TiBow Design titanium objects take advantage of crafts belonging to metalsmithing, graphic arts and painting.

The titanium object is shaped by hand with tools like pliers, hacksaws and pincers. Sometimes like in the case of the sculpture of titanium damascus rings, the rough-hew is made with a cnc mill.

Then, titanium is polished or textured through sandpapers, microcutters and polishing creams. Once obtained the desired reflection pattern, the painting decoration take place.

To produce different thicknesses of oxide we proceed in a way that reminds etching, applying masks to the surface and submerging it in an electrolytic solution instead than in acid. Different voltages are sent to the solution, in order to produce thicker or thinner layers of oxide, in relation to the desired colours. Further manufacturing may involve the use of burins, microcutters and conveniently modified brushes.

The titaniumchromic brush is not dipped in a paint. Its bristles are internally connected to a variable voltage DC generator, and they are used to transmit that voltage, with the corresponding colour, to specific areas of the object, leaving unaltered the previous oxidations in the rest of the object.

TiBow Design, Titanium texture samples.

TiBow Design, electrified brushes for titanium local colouring.

Let's have a look at how the colours arise on the titanium surface.

The colouring of our jewelry is not due to paints or enamels, but to the forming of a thin layer of transparent oxide on titanium surface.

Unlike other metals oxides, becoming themselves pigments reflecting the light of that specific colour while absorbing the others, titanium, exposed to the air, suddendly cover itself of a very very thin transparent coat (3-4 billionths of metre or nanometres).

This titanium oxide layer is so thin to position inside the size range of light frequencies: one nanometre corresponds to 10 Angström indeed. So, by the refraction and interference phenomenons, on the basis of the layer thickness some chromatic bands are reinforced while others are weakened or "cutted".

By mean of thermic or electrolytic treatments, we can vary the thickness of the titanium dioxide layer, obtaining therefore the desired colours.
These colours are exactly those which, in nature, we can observe in opals, on bird feathers, on butterflies wings and, of course, in the rainbow. The difference is that titanium colours are much, much more stable and enduring.

Fig. 1 - Electric potential, thickness of oxide coat and related colours on titanium (image courtesy of http://www.enco-journal.com).

Fig. 2 - The interference on oxidized titanium surface (image courtesy of http://www.enco-journal.com).

Here the phenomenon description in Pedeferri's words (Pedeferri is also the author of the illustrations above):

When we observe a titanium surface coated by an oxide film, our eye is reached by two overlapping light waves: one reflected by the upper face of the film, which is in contact with the athmosphere and the other by the lower face which, instead, is in contact with the metal (Fig. 2).
The second light wave has to make a double crossing of the oxide. Assuming the titanium surface to be illuminated by a monochromatic light, this wave can be in phase with the first only if its additional path contains a whole number of wavelenghts; otherwise it will be out of phase or even in opposition of phase if the path contains an odd number of half-wavelenghts.

Let's evaluate the two extreme cases. When there is perfect synchrony between the two oscillations - crest corresponds to crest, trough to trough - the two waves are reinforced by the overlapping. When on the contrary the two oscillations are in opposition of phase, their sum nullify them.
Of course, in intermediate situations we can have an additional interference or a subtractive one, hence strengthening or weakening of some hues.

Consequently, if we illuminate the titanium plate coated by a film of a definite thickness with white light, containing all colours, the two waves of a given colour, as is of a given wavelenght, will arrive to our eye in phase concordance, and that colour will be reinforced, while for another colour they will be in opposition, extinguishing that colour.
All the other colours will be in intermediate situations, being either reinforced or diminished.

Varying the thickness of the titanium oxide layer will vary both the colours being reinforced and those being dimmed or nullified, therefore varying the hue perceived by the observer.

TiBow Design, anodized and etched titanium necklace pendent.

TiBow Design, anodized and etched titanium necklace pendent.

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The titanium damascus

The titanium damascus is a metallic compound which is not as precious as gold. Nevertheless, we can consider it much rarer than common precious metals as it is produced only by a very few craftsmen in the World. Due to the extreme difficulty of perfectly welding the layers, only small quantity can be produced at a time.

The titanium damascus is created by mean of forge-welding, under controlled athmosphere and temperature, layers of different titanium alloys. Then various manufacturing procedures are applied; bending, twisting, imprinting, each accompained by a new forge-welding. Finally, the layers form drawings and lines that do belong to the inner structure of the object. With appropriate heat treatments and polishing, these drawings and lines will reveal as coloured stripings on the surface of the finished ornament.
Differently to what happens with the normal damascus made with carbon or stainless steels, where the stripings only take gray shades from black to white, the titanium damascus offers the coloured hues of titaniumchromy.

It is extimated that since the dawn of humanity a total amount of 121.000 tons of gold have been mined in the World, and actually the extraction carry on by 3000 tons a year.

Titanium damascus, instead, exists in a quantity which can be estimated in a few hundred pounds, summing that produced with the American procedure called "Timascus" to that produced with the Italian one by Valter Fornasier Fornasier, as of now, has produced a total amount of 100 pounds, including the experimental billets.

Most of this material is then wasted, as the jewels are carved by bigger pieces. From a four pounds billet, a few ounces only remains as commercial product.

Purchasing a titanium damascus jewel at TiBow Design you do not only aquire a unique model, but even rarest in the carved material.

Valter Fornasier, Titanium damascus necklace pendent.

Valter Fornasier/TiBow Design, Titanium damascus ring.


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