Xin xiang ceramic mug manufacturer Co,. ltd, Ceramics is a collective term for pottery and porcelain, and ceramics can be used as handicrafts, daily necessities and industrial supplies. As far back as the Neolithic era, China has a rough, simple style of colored pottery and black pottery. Pottery and porcelain have different textures and properties. Pottery, is a high viscosity, plasticity of the clay as the main raw material made of opaque, with fine pores and weak water absorption, hit the sound turbid. Porcelain is made of clay, feldspar and quartz, translucent, non-absorbent, corrosion-resistant, hard and compact tire, knocking sound brittle.
1. Definition
Ceramics is a collective term for pottery and porcelain. Traditional ceramics, also known as ordinary ceramics, is to clay and other natural silicates as the main raw material fired products, modern ceramics, also known as new ceramics, fine ceramics or specialty ceramics. Commonly used non-silicate chemical raw materials or synthetic raw materials, such as oxides (alumina, zirconia, titanium oxide, etc.) and non-oxide (silicon nitride, boron carbide, etc.) manufacturing. Ceramics have many advantages such as excellent insulation, corrosion resistance, high temperature resistance, high hardness, low density, radiation resistance, etc., and have been widely used in various fields. Traditional ceramic products include daily-use ceramics, building sanitary ceramics, industrial art ceramics, chemical ceramics, electrical ceramics, etc., with a wide variety and different properties. With the rise of high-tech industries, a variety of new special ceramics have also gained greater development, ceramics have increasingly become excellent structural and functional materials. They have higher than traditional ceramics temperature resistance, mechanical properties, special electrical properties and excellent chemical resistance.
2. History
Neolithic era, China has a rough, simple style of colored pottery and black pottery. To the Shang Dynasty (sixteenth century BC - eleventh century) glazed pottery and porcelain nature of the first hard glazed pottery has appeared. By the Wei and Jin Dynasties (220-420 A.D.), China had already accomplished the major invention of firing porcelain with a high degree of heat to produce a solid texture. During the Tang Dynasty (618-907 A.D.), the production technology and artistic creation of ceramics reached a high level. Exported to Japan, India, Persia and Egypt, played an important role in international cultural exchanges, won the "porcelain country". Ming and Qing dynasties (AD 1368-1911) ceramics from the production of blanks, decorative, glaze to firing, technology and more than the previous generation.
The history of Chinese ceramics development is long. Starting from the early Neolithic period when the most primitive pottery was fired to the invention of porcelain and its universal application, both technology and art have been progressing; in the process of adapting to the needs of people's survival and life, the types of ceramic objects fired have been increasing, the styles have been changing, and the intrinsic qualities have been improving. Ceramic objects of handicraft manufacturing technology, contains a rich scientific and artistic connotation, its expression is mainly through the shape and decoration, texture and color show. Ceramic production from raw materials to the transformation process of finished objects, must use the corresponding technology to complete, this is the process of people producing material materials, but also the creative development and the gradual formation of traditional crafts process.
From the history of the development of ancient Chinese ceramics, ceramic culture can be seen in the era of characteristics: the Qin and Han bold, Sui and Tang's majestic, Song Dynasty Confucian, Ming and Qing Dynasty exquisite, all in their respective historical stages, flashing the flame of its own time.
Neolithic Period
The colored pottery of the Neolithic period has a very proper shape, dense body, fine and unrestrained decorations, beautiful patterns, varied forms, unique artistic style, practical and rich cultural flavor.
Han Dynasty
By the Eastern Han Dynasty, mature porcelain had been fired. Three Kingdoms, two Jin and North and South Dynasties period of ceramics to "ancient and simple, simple and sparse, rich in heavy decorative flavor" as its distinctive features.
Tang Dynasty
Tang Dynasty, is the Chinese civilization and West Asia, the East Pacific Islands civilization and the Arabian, Mediterranean civilization mingled period. Tang Dynasty ceramics is famous for its "broad and fresh, thick and powerful, gorgeous and full" artistic style.
Song Dynasty
Song Dynasty is a period of national rationalization on the fruits of exchanges between Chinese and foreign civilizations. It is also one of the most representative stages in the history of Chinese culture, in which all kinds of foreign things were absorbed and digested, and turned into the physical space where Chinese people could see, live, play and travel. Cultural style became fresh, delicate, rational and fantastical, and heavy on reality. Song Dynasty, is the era of China's porcelain industry flourished. There were the famous "Ding, Ru, official, Brother, Jun" five kilns, but also the magnetic state kiln, Jizhou kiln, Longquan kiln and Jingdezhen kiln (Hutian kiln). Song Dynasty ceramics are famous for the cultural characteristics of "light and subtle, dignified and elegant, quiet and elegant".
Ming Dynasty
Ming Dynasty ceramics were fully developed, Longquan celadon, Dehua white porcelain, Shiwan Guangjun, Yixing purple sand, Shanxi enameled porcelain are famous, ceramic varieties, colorful, unique style. Ming Dynasty ceramics to "thick, dignified, rich in rich decorative beauty, fun, beautiful" style and independent of the forest of art and culture.
Qing Dynasty
Qing Dynasty ceramics, is another peak of the development of Chinese ceramics, a variety of varieties, materials, complete, especially in the colored porcelain achievements. Qing Dynasty ceramics to "delicate and gorgeous, quality fine art heavy, exquisite and gorgeous" and famous.
3. Development
Neolithic era
The emergence and development of ceramics, in fact, is closely linked with people's lives and production practices, in about 700,000 years ago in the primitive era, people drying mud with fire grill hard containers used for water, storage of food and so on, this is the initial generation of pottery. The latest archaeological data show that the earliest pottery site found in China is located in Jiangxi Wannian County in the immortal cave site, Guangdong Yingde Qingtang, Lingshan slippery rock cave, Guangxi Guilin ZhenpiPiYan. Its main varieties include gray pottery, colored pottery, black pottery and geometric printed pottery, etc., with rough techniques and novel and smooth compositions, showing the technical level of pottery making at that time.
Summer to Two Jin Dynasties
In the ruins of Yinxu of the Shang Dynasty, a lot of pottery pieces and various styles of pots were unearthed, and the decorations, symbols and characters on these pots were closely related to those of the oracle bone inscriptions and the blue wares of the Yin and Shang Dynasties, and the pots were no longer confined to containers at this time, and were widely used, which could be roughly classified into daily necessities, architecture, martyrdom and sacrificial gifts, and so on. After the Qin and Han Dynasties, ancient buildings were mostly constructed with wood, which was not easy to survive for a long time, so some great buildings, such as the Afang Palace in the Qin Dynasty and the Weiyang Palace in the Han Dynasty, could not be preserved in their entirety, but relics such as tiles and bricks can still be found in the remaining ruins, which can give a glimpse of the scale of the ancient buildings. The two Han Dynasty, glazed ceramics replaced a large number of copper daily necessities, so that the rapid development of pottery, due to the mastery of the processing skills, followed by the emergence of vivid and lively patterns and shapes of ceramic decorations, with high artistic value, which is the transition from pottery to porcelain bridge. Two Jin period to the North and South Dynasties ceramics main achievement is mainly reflected in the Yue Kiln, mainly celadon decorated with a high level of art.
Sui, Tang and Five Dynasties
Sui dynasty is short, but in the porcelain firing, but there are new breakthroughs, not only celadon firing, white porcelain also has a good development, in addition to this time in the decorative techniques have been innovative, such as in the artifacts in addition to the clay piece of an appliqué, is an example. To the Tang Dynasty, porcelain production can be metamorphosed to the mature realm, and cross into the real porcelain era, because the pottery and porcelain separate, care about the quality of white hard or translucent, and the biggest key to the temperature of the fire, the Han Dynasty produced porcelain, but the temperature is not high, the texture of the fragile can only be regarded as the original ceramics, and the development of the Tang Dynasty, not only the glaze development of the medicine is mature, the fire temperature to reach Celsius more than 1,000 degrees Celsius, so we say that the Tang Dynasty was really into the porcelain generation.
Song and Yuan period
Porcelain industry in the Song Dynasty with the emergence of new kilns around the continuous development, the emergence of a number of famous kilns, the so-called five kilns - Ding, Ru, the official, brother, Jun is the representative of the Song Dynasty to form a variety of colorful and beautiful and simple shape, decorative methods of diversified features. The official and private kilns famous porcelain styles are different, a hundred flowers compete, each showing the beauty of a unique style. Yuan Dynasty period there are new developments, such as the rise of blue and red glaze, a large number of colored porcelain popular, driving the development of porcelain after the Ming and Qing dynasties.
Ming and Qing Dynasties
China's pottery development to the Ming Dynasty and into a new journey, before the Ming Dynasty porcelain to celadon, and after the Ming Dynasty to white porcelain, especially blue and white porcelain, five colors become the main products of the Ming Dynasty white porcelain, at this time the tire also tends to be thin, fine, white needs, in the billet body to remember the styles have also begun to date, the age of the hall, the name of the people have, so that the study of the evidence to have a more accurate identification.
Qing dynasty Chinese porcelain can be said to be the peak of the early Qing dynasty porcelain production technology is highly skilled, fine and gorgeous decorations, the Qing dynasty colored porcelain in the Ming dynasty on the basis of a great development, technological innovation, differentiation of more color, ink color, blue color, gold color also appeared in the five-color porcelain picture, the color of the light and elegant is the characteristics of its, thus enriching the decoration of porcelain in the Qing dynasty.
Modern pottery
In the production of modern ceramics, the raw materials are taken in an eclectic way. Combination with a variety of materials, and use, penetration, produced a complementary artistic effect, so that modern pottery has both rich expressive and fully coordinated, surface decoration and spatial processing also ascended to a higher level. Modern pottery focuses on texture performance, not to pay attention to whether it is rough or fine raw materials, materials are no longer limited to porcelain clay and pottery clay, but intentionally break through the use of traditional ceramic raw materials, the use of different characteristics of clay, to play a variety of materials of the potential beauty, as long as the kiln can be fired by the mud, sand and other materials can be used in the service of the.
4. Characteristics
When it comes to ceramic materials, it is inevitable to talk about pottery and porcelain separately, we often say ceramics, refers to the two types of pottery and porcelain together. In the creative field, pottery and porcelain are ceramic art is an important and indispensable part of the ceramic art, but pottery and porcelain are qualitatively different.
Pottery, is a high viscosity, plasticity of clay as the main raw material made of opaque, with fine pores and weak water absorption, hit the sound turbid. Porcelain is made of clay, feldspar and quartz, translucent, non-absorbent, corrosion-resistant, hard and compact tire, knocking sound brittle.
5. Classification
There is no uniform classification of ceramic materials, ceramic materials are usually divided into glass, glass ceramics and engineering ceramics 3 categories. Engineering ceramics are divided into ordinary ceramics and special ceramics two categories. One of the ordinary ceramics, also known as traditional ceramics, special ceramics, also known as modern ceramics.
Ceramic materials are a class of inorganic non-metallic materials made of natural or synthetic compounds through molding and high temperature sintering. Has a high melting point, high hardness, high wear resistance, oxidation resistance and other advantages. Can be used as structural materials, cutting tool materials and mold materials, because ceramics also have some special properties, and can be used as functional materials.
Specialty Ceramics
Specialty ceramics, also known as modern ceramics, according to the application of special structural ceramics and functional ceramics, such as piezoelectric ceramics, magnetic ceramics, capacitor ceramics, high-temperature ceramics. Engineering the most important high temperature ceramics, including oxide ceramics, carbide ceramics, boride ceramics and nitride ceramics.
General Ceramics
Common ceramics, also known as traditional ceramics, are made from clay (Al2O3-2SiO2-H2O), quartz (SiO2) and feldspar (K2O-Al2O3-6SiO2). By adjusting the ratio of the three, different electrical resistance, heat resistance and mechanical properties can be obtained. General ceramics are hard but brittle, with excellent insulation and corrosion resistance.
General ceramics are usually divided into two categories: daily-use ceramics and industrial ceramics. Daily-use ceramics are divided into: ceramic mugs and ceramic tableware.
Ceramic mugs are specifically categorized as:
a). Insulated mugs, ultra-thin mugs, single-layer mugs, double wall mugs.
b). Stoneware mugs, bone china mugs, ceramic mugs, new bone china mugs, enameled mugs, jade porcelain mugs.
c). Travel mugs, coffee mugs, tea mugs, soup mugs, wine mugs, cookie mugs, hot pot mugs, cell phone mugs, espresso mugs, black tea mugs, beer mugs, sublimation mugs, photo mugs, color changing mugs, music mugs.
d). High temperature ceramic mug, medium temperature ceramic mug, low temperature ceramic mug.
e). White mug, monochrome glaze mug, two-color glaze mug, multi-color mug.
6. Production process
6.1. Raw materials
Most of the raw materials used in ceramics and other silicate products are natural minerals or rocks, most of which are silicate minerals. These raw materials are diverse, resource-rich, widely distributed in the earth's crust, which provides favorable conditions for the development of the ceramic industry, the early ceramic products, are made with a single clay mineral raw materials, later, with the development of ceramic technology and products to improve the performance requirements, people gradually in the blanks added to other mineral raw materials, that is, in addition to clay as a plasticity of raw materials, but also the proper Add quartz as barren raw materials, add feldspar and other alkali metals and alkaline earth metals containing minerals as raw materials for flux. At present, there is no uniform method of classification of ceramic raw materials, generally according to the process characteristics of raw materials are divided into plasticity raw materials, barren raw materials, flux raw materials and functional raw materials of four categories.
6.1.1 Plasticity raw materials
Plasticity raw materials are mainly clay minerals, they are layered structure of the silicate, its particles generally belong to the microscopic size (less than 10μm), and has a certain degree of plasticity of the minerals. For example, kaolin, polyhydric kaorakuorin, bentonite, china clay and so on. Plasticity raw materials in the production of the main role of plasticization and bonding, which gives the billet plasticity and injection molding properties, to ensure the strength of dry billet and after firing a variety of performance, such as mechanical strength, thermal stability, chemical stability, etc., which is the basis for the molding can be carried out, but also clay ceramics into the basis of the ceramics.
6.1.2 Barren raw materials
The mineral composition of barren raw materials is mainly non-plastic silicon, aluminum oxides and oxygenated salts. Such as quartz, opal paraffin, clay calcined clinker, waste porcelain powder. Barren raw materials in the production of viscosity reduction, can reduce the viscosity of the blank, after firing part of the quartz dissolved in feldspar glass, to improve the viscosity of the liquid phase, to prevent high-temperature deformation, after cooling in the porcelain billet in the role of the skeleton.
6.1.3. fusible raw materials
The mineral composition of the fusible raw materials is mainly alkali metals, alkaline earth metal oxides and oxygenated salts. Such as feldspar, limestone, dolomite, talc, lithium mica, granite and so on. They play the role of flux in production, and after melting at high temperature, they can dissolve part of quartz and kaolin decomposition products, and the high viscosity glass after melting can play the role of high-temperature cementation. At room temperature, it also plays the role of viscosity reduction.
6.1.4 Functional raw materials
Raw materials and auxiliary raw materials other than the above three categories are collectively called functional raw materials. Such as zinc oxide, zircon, color, electrolyte and so on. They do not play a major role in the production, is not a necessary component of the porcelain, generally a small amount of accession that can significantly improve the performance of certain aspects of the product, and sometimes to improve the performance of the blank glaze without affecting the performance of the product, thus facilitating the realization of the production process.
6.2. Billet Formulation
After the selection of raw materials, to determine the amount of various raw materials in the blanks and glazes is a key task, because it is directly related to the quality of the product as well as the development of technology systems.
The design of billet formula is a heavy and complex work. At present, ceramic products are changing rapidly, the performance requirements of ceramic products are changing, and, ceramic production of a wide range of raw materials used in the chemical composition of the mineral composition as well as their process performance has a great deal of difference, and can not do the standardization of raw materials. Around the different levels of technology, equipment, management of enterprises, and ceramic product performance indicators are affected by a variety of factors, so, in the design of billet formulations, can not rely only on theoretical calculations, otherwise, it is difficult to get satisfactory results.
In short, the following basic principles should be followed in the formulation design.
6.2.1. in the chemical composition to meet the performance requirements of ceramic products. Raw materials from the chemical composition should be fully analyzed and performance comparisons, to find out the performance characteristics of the raw materials, depending on whether they have or close to the required performance of the product.
6.2.2 The performance and proportion of raw materials used to meet the production process and the final physical properties of the product requirements. Should take into account the purity of raw materials, forming properties, firing properties, color and lustre after firing, as well as the strength and transparency after firing, thermal stability, and sometimes make some changes in the chemical composition of the blanks to meet the requirements of the physical properties of the product.
6.2.3. Due consideration should be given to the size of the existing plant and the specific production conditions. Can not be due to the use of formulations and a large number of changes in the existing production process parameters and invest a large amount of money to buy equipment and technological transformation. Billet formula design, should be from the preparation of raw materials forming and firing and other aspects of the examination of their process parameters, and as a fundamental condition, only such a formula, only has the practicality and scientific value.
6.2.4 To consider the economic rationality. The raw materials should be locally sourced, the amount of materials used, rather near than far, make the best use of things.
6.3. Billet Preparation
Daily-use ceramic blanks usually refers to the ceramic raw materials after batching and processing, the formation of a multi-component mixture with molding properties in line with the quality requirements for molding. According to the forming method of different products blanks have different characteristics, were made of water content of 19% to 26% of the plastic molding clay, water content of 30% to 35% of the slurry injection molding slurry water content of 4% to 7% of the dry pressure molding powder and hot pressure injection molding slurry or dry powder and wax uniformly mixed with the wax cake, etc. Blanks have different preparation processes, should be based on the characteristics of raw materials, equipment, use of conditions, production scale, product quality requirements, the preparation of ceramic blanks. The choice should be made according to the characteristics of the raw material used, the conditions of use, the scale of production, the quality requirements of the product and the technical and economic indicators of the preparation process itself. Bad material processing methods or process control is not appropriate, will not only reduce production efficiency, increase production costs, but also affect the process performance of the blank and the use of product performance.
6.4. Forming
Forming of ceramic products, that is, using different methods to make blanks with a certain shape and size of the blanks. According to the blank moisture content and performance differences, ceramic molding method is divided into plastic, grouting method and pressing method.
(1) Plastic molding
Plastic forming method is under the action of external forces, so that the plasticity of the blank plastic deformation and made of blank method. Because of the external force and different methods of operation, the ceramics can be divided into two categories of hand-forming and mechanical forming sculpture, printing blanks, billet, hand pinch, etc. belongs to the hand-forming, these forming methods are more ancient, mostly used in the manufacture of art ceramics. China ceramic mug manufacturers think the spinning and rolling molding, is the current factory widely used mechanical molding methods, can be used for plates, bowls, cups and saucers and other products production. In addition, in other ceramic industry also used extrusion, billeting, pressing, rolling film and other plastic molding methods.
(2) Slurry molding
Slurry molding is the use of porous model of water absorption, the slurry into which the molding method, this molding method is highly adaptable, where the shape is complex, irregular thin-walled, thick tire, large volume and size requirements are not strict products can be used to mold the slurry method. Such as daily-use ceramics in the vase, soup bowl, oval plate, teapot handle, etc. can be molded using grouting method.
Grouting after molding the body structure is uniform, but its water content is large and uneven, drying shrinkage and firing shrinkage is larger.
In addition, from the production process, its production cycle is long, manual operation, labor intensity, large footprint, model consumption. With the continuous progress of the production process and the continuous development of slurry forming machinery, these problems will be improved and solved, so that slurry forming is more suitable for modern ceramic production.
Slurry molding operation process Slurry molding operation process according to the product type, different slurry properties need to go through the following procedures.
6.4.2.1 Closing the mold
Before closing the mold, the working surface of the model should be cleaned and no dry mud or dust should be left. And check whether the working surface of the mold is smooth and clean, there are no holes and lubricating oil traces. Such as normal can be carried out to close the mold, assembled model if a large gap, with soft mud will be closed at the gap blocking, so as to avoid leakage of slurry. When using the model should not be too dry or too wet, the amount of water is generally controlled at 4% -6%.
6.4.2.2 Grouting
For single-sided grouting, the slurry filled model can be, such as mud layer thickening to the required thickness, pour off the model of excess slurry, in order to avoid pouring off a small amount of residual slurry in the billet in the body of the uneven distribution of the surface, the production of slurry also need to pour off the slurry after the billet with a billet model for the dumping of slurry to ensure that the distribution of residual slurry to ensure that the distribution of mud is uniform to avoid mud wisps produced. For double-sided grouting, must be supplemented with slurry until the model of the cavities within the slurry all into the blank. There is no need to pour and dump the slurry.
6.4.2.3. Drying of green billets
Just formed due to the high water content of the injection, low strength and can not immediately demolding, need to take the mold drying for a certain period of time, this drying is called green billet drying, in the green billet drying period, due to the evaporation of water and the mold continues to absorb water, the injection of the water continues to decline, the billet contraction and detachment of the model, and at the same time gradually improve the strength, then can be demolded.
6.4.2.4. demolding
After demolding, the body should be held gently, put flat, put right, put stable, and prevent vibration.
6.4.2.5 Bonding
Bonding is the manufacture of pots, mugs and some small vases, altars and other daily-use porcelain and art porcelain, sanitary porcelain and other blanks can not be molded in one process, the bonding process refers to a certain consistency of the bonding slurry will be shaped into their respective parts bonded together.
(3) Press molding
Compression molding is the use of pressure will be placed in the mold of the powder compressed to the structure of the compact, with a certain shape and size of the blank forming method. According to the moisture content of the powder, it can be divided into dry pressure molding (moisture content of less than 6%) and semi-dry pressure molding (moisture content of 6% to 14%) pressure molding billet moisture content is low, dense billet, drying shrinkage is small, the product shape and size of the accurate, high quality. In addition, the forming process is simple, the production volume is large, easy to mechanize the mass production, for the flat system with regular geometry.
6.4.3.1. Preparatory work
Before proceeding to the production of ceramic mugs by the pressing method, the following materials and tools need to be prepared first:
Clay block: choose a suitable clay block for the production and select the right type of clay according to the needs and requirements of the work.
Molds: make or prepare suitable molds, molds can be silicone molds, ceramic molds, plaster molds, etc., according to the shape and size of the work to choose the right mold.
Pressing tools: Hand pressing tools can be used, such as press boards, press molds, etc., or mechanical pressing equipment can be used, such as billet presses.
6.4.3.2. Pressing process
Preparation of molds: Clean the molds and apply a thin layer of lubricant where needed to prevent the clay from adhering to the molds.
Clay Placement: Place the clay block in the center of the mold, making sure that the clay is in close and even contact with the mold.
Compacting Clay: Compact the clay using hand or mechanical compacting tools to fill the space in the mold and maintain an even thickness. During the pressing process, water can be added or the humidity of the clay can be adjusted to ensure the pressing effect and the plasticity of the clay.
Removing the mold: After the clay is compacted and shaped, gently remove the mold from the clay, being careful not to damage the shape and structure of the clay.
Trimming and decorating: trim and decorate the clay work according to the needs, you can use the tools to trim the edges, carve the texture, etc., or decorate the surface with color painting and applique.
6.4.3.3. Firing and Finishing
After completing the ceramic pieces made by the pressing method, they need to be fired. The temperature and duration of firing depends on the type of clay and the size of the ceramic mug, and the temperature is usually increased gradually during the firing process to ensure that the piece is fully sintered and reaches the desired hardness and strength. Eventually, after firing, the ceramic coffee mug will take on the desired texture and color, completing the process.
6.5. Glaze
Glaze is a very thin uniform vitreous layer fused to the surface of ceramic products.
Unglazed ceramic products usually have a rough surface without light, easy to absorb moisture, easy to stain, easy to erosion and other weaknesses, even if the degree of sintering is very high, but also as a result of its beauty, health and electromechanical and other properties. When the blank surface applied a layer of vitreous enamel layer, can make the products to obtain a glossy, hard, non-absorbent surface, not only can improve the optical, mechanical, electrical, chemical and other properties of ceramic products, but also to improve the practicality and artistry also plays an important role. Therefore, glazing the surface of the blank is very necessary.
6.6. Drying
The process of dehydrating materials with the help of heat is called drying. After the formation of a variety of blanks, usually contains high moisture, especially plastic molding and injection molding of the blanks, is still in the plastic state, the strength is very low, not conducive to the subsequent process of processing and transportation. Therefore, in the blank into the firing must be based on the operational requirements of each process, segmented drying, until the final moisture to meet the requirements.
The purpose of drying the billet is to: reduce the moisture content of the billet, so that the billet has enough adsorption of glaze slurry capacity; improve the mechanical strength of the billet, reduce the breakage in the process of transportation and processing; so that the billet has the lowest moisture into the kiln, shorten the firing cycle, reduce fuel consumption.
6.7. Firing
Raw material is the basis, firing is the key. In the ceramic production process, firing is one of the vital processes. The firing process of ceramic products is in a certain temperature and atmosphere conditions, after forming, glazing, drying ceramic billet for high temperature treatment, so that a series of physicochemical changes, the formation of a certain mineral composition and microstructure, and ultimately obtain a variety of characteristics of ceramic products billet in the firing process to occur a series of physicochemical changes, such as expansion, contraction, the generation of gas, the liquid phase of the Appearance, the disappearance of the old crystalline phase, the formation of new crystalline phase. In different temperatures, atmosphere conditions, the content and extent of the changes are not the same, thus forming a different mineral composition and microstructure, determining the different quality and performance of ceramic products.
The glaze layer on the surface of the blank in the firing process also occurs in a variety of physical and chemical changes, and ultimately form a glassy substance, thus having a variety of physical and chemical properties and decorative effects. Common firing process can be divided into a firing and two firing. A firing, is the raw billet glazed, dried into the kiln at high temperatures after a firing into products. Two firings, is the unglazed blanks, after drying, the first firing, and then glazed, and then the second firing (glaze firing). A firing process to simplify the process, reduce the heat loss during firing, two firing to improve the strength of the blank, is conducive to the mechanization of subsequent processes, automation, reduce breakage, improve the quality of the glaze. The actual production should be selected according to the specific conditions of the product.
The firing process is carried out in specialized thermal equipment called kiln. There are many types of kilns, which should be selected according to the different products. At the same time, firing is also often used to a variety of kiln, the rational choice and use of kiln, to improve product quality, energy saving, reduce production costs is also important. There are many factors affecting the firing, in the firing process if not properly controlled, not only waste of fuel, but also will directly affect product quality, and even cause a large number of waste products, bringing undue losses to the enterprise. Therefore, we only master the billet in the high-temperature firing process of the law of change, the correct choice and design of the kiln, the scientific development and implementation of the firing system, the strict implementation of loading and burning operating procedures, in order to improve product quality, reduce fuel consumption, and obtain good economic benefits.
6.8. Decoration
Decoration is an important means of artistic processing of ceramic products, it is the unity of technology and art. Through the ceramic products for appropriate decorative processing, not only can improve the artistic value of the products, bring people the enjoyment of beauty, but also significantly improve the appearance of the quality of the products, improve its economic value of ceramic decorative methods, each of them has its own artistic characteristics.
According to the varieties of ceramic products, process characteristics and different decorative techniques can be divided into the following types of decoration
Painted decoration: including glaze decoration, such as new color, ancient color, pastel, broad color and other glaze hand-painted and glaze appliqué, printing, brushing, spraying color, photographic decoration, electric light color and bright gold, polished gold, corrosion of gold, etc.; underglaze decoration, such as underglaze blue, glaze, underglaze red, underglaze, underglaze color, underglaze spraying and underglaze appliqué, etc.; glaze color decorations, such as low-temperature glaze color, glaze color, in the Korner temperature, etc.
Art glaze decoration: including color glaze, flower glaze, crystalline glaze, no light glaze, crackle glaze, variegated glaze, fluorescent glaze and so on.
Sculpture decoration: including pinching, piling flowers, picking flowers, carving, hollowing, relief, dark carving, round carving and molding.
Comprehensive decoration: including blue and white lingerie, crystal carving and stacking flowers, color glaze porcelain, blue and white doucai, colored art glaze, etc.
Other decorative methods: including color blanks, make-up clay, color granule blanks, bleeding, grinding and polishing, screen printing, patchwork decoration and so on.
