Ceramics and Coloring Method

Ceramics is the general term for pottery and porcelain. Chinese invented pottery as early as about 8000-2000 BC (Neolithic Age). Ceramic materials are mostly oxides, nitrides, borides and carbides. Common ceramic materials are clay, alumina and so on. Ceramic materials generally have high hardness, but poor plasticity. In addition to the use of food utensils and decorations, it also plays an important role in the development of science and technology. The flexibility of its usage is still found in various creative applications in today's culture and technology.

1. Origin of Chinese Ceramics

China is one of several ancient civilizations, and has made significant contributions to the progress and development of human society. The achievements in ceramic technology and art are of special significance. The predecessor of ceramics was primitive celadon, which was the product of the transition from pottery to ceramics. The earliest primitive celadon in China was found at the Fenglongshan Cultural Site in Shanxi Province, dating back to about 4200 years ago. The original celadon was widely distributed in China, and was found near the Yellow River, the Yangtze River and the southern region.

In China, the appearance of true ceramics widely acknowledged was in the Eastern Han Dynasty. Its billet body is made of kaolin or ceramics stone and other composite materials, fired in the high temperature. The carcass is hard, dense, thin and not absorbent. The outside of the carcass mask with a layer of glaze, and the glaze should be smooth. The vast areas in the middle and lower reaches of the Yangtze River are rich in raw materials and fuel resources, so the pottery industry in this area develops rapidly, and there are numerous and extensive kiln sites. Through field investigation and excavation, some main kilns in this period are basically clarified. For example, Yue Kiln, also known as "Yuezhou Kiln", started in the Eastern Han Dynasty and declined in the Northern Song Dynasty. Besides, there were Ou Kiln in Zhejiang, Hongzhou Kiln in Jiangxi, Yuezhou Kiln in Hunan, Yixing Kiln in Jiangsu and so on. During this period, ceramics replaced part of pottery, bronze and lacquer, and became one of the most important utensils in people's daily life. It was widely used in catering, furnishing, study utensils, funeral and so on.

During the early and middle periods of the Qing Dynasty, the social economy entered into a prosperous period, and the Chinese ceramics making technology reached a historical peak. The ceramics making technology made great progress in the Qing Dynasty. Most of the techniques and varieties existing in the Ming Dynasty were improved or innovated.

2. Use of Chinese Ceramics

In addition to vessels for food, water and liquor, ceramics are also widely used in stationery, such as pencil holders, water bowls, inkstones and so on. The function of the water bowl is only to hold ink grinding water, but the shape is very plentiful. There are frog shape, bird shape, rabbit shape, cow shape and so on. Ceramic stationery, which is related to the worship of reading and scholars, is widely used. The decoration features of this period are obvious. There are often patterns of life scenes on the objects, which are delicate and vivid. They truly reflect the social outlook of different period, and also provide evidence for people's research on architecture, music, dance, religion, animal husbandry and other topics. The exaggerated deformation of animal image is drawn on some daily-using articles such as candlestick, oil lamp, and water basin. It reflects the aesthetic consciousness of the society for different periods, and enriches people's spiritual life. 

3. Production of Chinese Ceramics

The production of Chinese ceramics has enjoyed a high reputation in the world. Since the Han Dynasty, various plant ashes containing different elements of clay and different chemical perfection have been used as colorants to decorate ceramic products. With the development of society, inorganic compounds of transition metals are also commonly used as pigments. However, while the surface spraying of the existing coloring process is heavy, wastes raw materials, and has been used for a long time, the ceramic glaze at the joint of the ceramic ware will have cracks and other aging phenomena. 

4. Coloring Method of Ceramics

As Qing Dynasty ceramics reached a historical peak, decorative ceramics made great progress. There were more different colors, such as ink color, blue color and gold color appearing on the colorful ceramics picture. People also created some new decorative varieties, such as pastel, enamel color, purple sand, weaving gold, black porcelain, Shiwan plastic, and so on. The simple and elegant color is its characteristics, thus enriching the Qing Dynasty ceramics decoration and making Chinese ceramics’ glory.

Nowadays, ceramics with their excellent performance play an important role in the new era. When we look back, we will find that earlier ceramic products are black or white, with a single color. Although ceramics have the texture and luster of jade, people are very fond of relying on the "natural color". However, in this era of appreciating appearance, black and white only makes people aesthetic fatigue. 

The combination of ceramics and technology offers a glimpse into the new world of art. The colored ceramic products are rare, so we talk about the ceramic coloring method.

(1) Glazing 

In the production of ancient ceramics, glaze paste is applied on the surface of ceramic blank, and then sintered to make colored ceramic products. However, in the coloring of ceramic cover plate, this coloring method will lose the hardness of ceramic cover plate itself. The surface of precision ceramics is extremely dense, and the adsorption force of glaze and ceramic surface is low, so the color is unstable. Most importantly, there is no glaze that can be adsorbed on the surface of nano-zirconia.

(2) Immersion Penetration

The ceramic blank is soaked in colored solution, and then sintered into colored ceramic products. This coloring method is simple to operate, but easy to color uneven. And color penetration depth is shallow, which is affected by the operation.

(3) Coating

It is common for the coating process to be applied to precision ceramic coloring. For example, the ceramic cover plate of cellphone is coated with color film on the surface of the cover plate by the coating process. The shortcomings of the color film plating on the surface of precision ceramic materials are also obvious, easy to scratch, and poor durability. There will be "paint off", and the ceramic color film will lose the texture of jade.

(4) Powder Coloring

The surface coloring method of ceramic products has more or less shortcomings, so the major upstream enterprises focus on the research on the color of ceramic powder. Cobaltous Oxide can be injected into ceramic raw materials, and then the colored ceramic powder is formed, sintered, post-processed and other processes to finally make colored ceramic products. Cobaltous Oxide is the coloring agent which can keep the color diversity of ceramics. This is beneficial to the use of ceramics.