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     The History and Technique of Ceramics
                

 

The "CERAMIC" word drift of the Greek term KERAMIKE, KERAMOS derivation, that means clay. Ceramics are the set of activities destined to the elaboration of all the species of objects, with adobe of any class, decorated or not, using it property that possess the molding clay easily in the raw adobe state (wet), acquiring hardness to the measure that advances its drying or for cooking effect.

It was during the Neolithic period, phase of the development technician of the societies human beings, correspondent to its access to a productive economy, that the ceramics were invented. This period, characterized for the development of new techniques has however as factor of primordial importance the establishment of new relations between the man and the natural way, decurrently of the discovery of ways to control and to develop the resources for its sedentary life.

It was considered during much time that the ceramic was one characteristic of this period. However the recognition of a pre-ceramic Neolithic period in the Next East (Jericó) and the ceramic vases discoveries in nomads groups dated of about 6000 AC. in Japan, compels us to consider it the existence of two phases: the pre-ceramics between the end of VIII millennium AC. and the principle of the VI and ceramics to follow to this date and was drawn out until the age of Bronze.

It was in the Southwest of Asia (Iran, Palestine and South of Turkey) that spontaneity gave the wheat and the barley, as well as existed in the wild state bovine and goat cattle that had allowed the revolution (passage to a production economy) above referenced.

It is not therefore to find odd that the initial development of ceramics if has given in the Next East, seen to have there been that the necessity was verified to store collected foods of agriculture; of houses to shelter an increasing population; of symbols that satisfied the spirituals necessities and ovens that transformed the decorative wheat's flour into bread that led to the construction of vases, bricks, statuettes and elements in clay.

How to Portugal has that to relate some following aspects: it had a first period where if they had revealed the European and Mediterranean influences for the appearance and development of this art, through the "invaders" in the first case and of the merchants in second. The appearance of a specific type of ceramics proceeding from a situated culture in the Tejo's Valley and that later was spread for all the Europe: the campaniform ceramics.


The existence of typical ceramics (ceramic Iberian), to the time of the Romans arrival and the importance of these and later of the Arabs for the future development of the pottery.
The existence of various regional types during the Average Age, some of which last until to the present.
The great development verified in last centuries XVII and XVIII, especially in this last one, due to existence of countenance ceramists as Brioso and Vandelli and to the foundation of Plant of the Rato, that was in the base of the appearance of other important plants for all the territory. The appearance in century XIX of the porcelain (Vista Alegre) and of the fine faïence (Sacavém) in part as reaction to the invasion of our market for English products, better and cheaper, because manufactured for the new processes left the Industrial Revolution.

The increase of the number of plants verified in the ends of century XIX and first decades of century XX and its decrease in the following decades, as consequence of the industrial concentration that was mark of the "great rising industry", process that the ceramics were not indifferent.

Ceramic it is the common denomination to all the articles or objects produced with clay and burnt/baked to the fire. The transformation of the adobe in ceramics happens during the burning. When the clay is burnt and if it becomes firm, in its first burning get the call biscuit, that although more not to come back to the plastic state still it possess fragile characteristic, therefore to fall themselves in the soil or to take a stronger collision, has been broken in many pieces.

The clay exists in all terrestrial surface. Some types are found at open sky and others in underground mines or deposits. The clay when removed of the nature generally it contains undesirable bodies, organic impurities, and therefore needs to be benefited through mechanical and chemical processes. For each category of the ceramic production the production of the argillaceous masses needs the addition or the withdrawal of elements in its composition, in accordance with its application, thus preventing the occurrence of cracks. Of the many existing types of clay the masses ceramic are produced that are used in the manufacture of ceramic utensils as roofing tiles, bricks, floors, etc.; that it is the structural ceramic call.

The masses of adobe are raw employees in the construction of housings.
It has the called white ware in sanitary parts, tiles, electric, conducting floors of high impact, refractory, electric insulators, etc. And the ceramic masses for the artistic ceramic called.

The Ceramics can be defined as material inorganic, nonmetallic gotten generally after thermal treatment in high temperatures. The ceramic materials are manufactured from natural and synthetic raw materials classified in. The natural ones more used industrially are: 
clay, caulino, quartz, feldspate, filite, talc, calcite, dolomite, magnetite, chromites, bauxite, graphite and zirconium 

The synthetic ones, among others include alumina (aluminum oxide) under different forms (calcimined, electro funded); silicon carbonate and the most diverse inorganic chemical products.
Ceramics have electric properties as isolating of high-voltage, in resistances, as the memory in computers, candles in the internal combustion of engines and, more recently, in applications of superconductors high temperature. 

Ceramics are essential for the construction industry, for the petrochemical industry, to generate electricity, for the communications, space exploration, medicine, sanitary. Porous porcelain done ceramics filters that can isolate microbes and bacteria of milk and drinking waters, separate dust of gases and remove particles solid of liquids.
Ceramics shields, which is light and resistant to the impact, have been confectioned to protect military airplanes, vehicles and soldiers. Ceramic mono-crystals have important mechanical applications, electric and optic. So delicate ceramics include items that they can be broken by a light touch, so resistant that they can protect our proper body and so lasting that they remain after thousand of more remote years disclosing to us it history of our ancestral ones.

One of the operations most important of the confection of objects in ceramics is the glass. The objective of the glass is to become impermeable objects of adobe to the water, and moreover it is also of giving color to them. They can be gotten glass of some qualities- of color, colorless, transparent or cloudy.

For the application of the glass, it is started for glassing the part.

After the glass being dry, it is painted the piece, using or not glass inks for ceramics of colors.

The glassed objects have of being placed in the oven in top of small adobe tripods, with the greater well-taken care, and in way not to be leaned ones to the others. The objects go then to the cooking, to glass: in this cook the oven heats until the final a temperature of 1.000 the 1,0400, in accordance with the instructions that follow the dust of glass. Of this time the temperature regulator of the oven can be put in the maximum. If to appear in the glass small cracks, is because glass are not of appropriate quality for the type of used adobe (the contraction coefficient was different). These containers are badly waterproofed.