Firstly, the glass-ceramic composite plate absorbs the advantages of ceramic plate, such as high mechanical strength, strong toughness, good impact resistance and high chemical corrosion resistance. Therefore, the mechanical properties of this composite plate are better than those of pure glass-ceramics, and the comprehensive properties of acid resistance, alkali resistance and chemical cleaning solution are also better than those of pure glass-ceramics, which undoubtedly improves the service performance of glass-ceramics. At the same time, it can also reduce the weight of plates and broaden the application of high-rise buildings.
Secondly, the production of pure glass-ceramics plates, especially the sintering method, mostly adopts shuttle kiln firing and manual polishing machine polishing. Therefore, most of these productions are intermittent. If the roller kiln is used for firing, its cross section will increase, and its roller must use high-grade refractory with high load and high softening point, and it is also inseparable from high-grade refractory as its backing plate. The production of ceramic plates is carried out through a mature, highly mechanized and automated continuous production line. Glass-ceramic composite plate is made by laying glass-ceramic particles on the surface of sintered ceramic plate (which also plays the role of refractory pad) and firing it in ordinary ceramic roller kiln. Then the polishing process is completed on a continuous polishing line. Undoubtedly, this composite plate makes the production of glass-ceramics continuous, mechanized and automated, and greatly improves the output of glass-ceramics. At the same time, energy consumption will be greatly reduced. This meets the requirements of energy saving and consumption reduction in building materials industry.
Finally, a considerable part of the raw materials used in glass-ceramics are chemical raw materials, and qualified glass-ceramics particles can only be produced after high-temperature melting, water quenching, drying, sieving and crushing, all of which increase the cost of glass-ceramics. Most of the raw materials used in ceramic plates are natural materials, and the cost of making ceramic slabs by ball grinding, spray drying, molding, drying and sintering is relatively low. On the other hand, the glass-ceramic composite plate consists of 1/3 thick glass ceramic with high cost and 2/3 thick ceramic blank with low cost. Obviously, compared with pure glass-ceramic board, glass-ceramic composite board can greatly reduce the cost and obtain more economic benefits. Sitar
That is, in the middle and late 1990s, pure glass-ceramic plates with wollastonite as the crystal phase have been relatively mature and mass-produced. This new material has appeared in many exhibitions of building materials at home and abroad, causing widespread repercussions.
Soon after, there were invention patents about composite glass-ceramic particles on the surface of ceramic tiles, including an invention patent on June 5, 2000 with Dai et al. as the inventor and patentee (invention name: new method for producing glass-ceramic composite tiles). In fact, they have already carried out research in this field as early as 1997, and tried several products in the former Beijing Beichen Ceramics Co., Ltd. that year. During the period 1998 ~ 1999, we went to Inner Mongolia Dongsheng Dongqiao Ceramics Co., Ltd., Beijing Ceramics Factory, Foshan Dong Peng, Daewoo Glaze, Oushennuo, etc. for popularization and application, but for various reasons, we failed to realize the industrialization of scientific and technological achievements. The main reason is that the first generation of glass-ceramics (that is, wollastonite crystal phase) has many intractable defects, which hinder the normal production of the first generation of glass-ceramics plates.
Around 2002, several large manufacturers in Foshan (including Bode, Xinzhongyuan, Jiajun, Oushennuo, etc. ) industrial production has been realized one after another. In the continuous production practice, we gradually overcome (or basically overcome) the defects of the main pores in the first generation of glass-ceramics, and successfully put the products on the market. The landmark events are: in August 2002, the world's first self-developed "Seiko Jade" was born in Bode, and the national invention patent was declared, marking the birth of mainstream microcrystalline stone; The first generation of glass-ceramic composite plate is famous for its white appearance, bright and soft luster, good hardness and wear resistance, and good acid and alkali resistance. However, because its crystals grow inward at the edge of the retained particles, the crystal flowers appear monotonous. Sitar
It was originally developed to solve the technical problem that the first generation of glass-ceramics are prone to porosity. According to the sintering formula of glass powder
[1]: Δ l/l0 (shrinkage) =Ktγ/ηR (where: k is the coefficient, t is the sintering time, γ is the surface tension of glass, η is the viscosity of glass, and r is the particle size of glass powder). It can be seen that the sintering degree of glass powder (shrinkage) is directly proportional to the surface tension of glass and inversely proportional to the viscosity of glass.
In addition, according to the internal pressure formula of bubbles in glass liquid
[2]: p = P x+P H+2γ/r (where: P x is atmospheric pressure, P H is hydrostatic pressure of molten glass, 2γ/r is internal pressure caused by surface tension of molten glass, γ is surface tension, and r is bubble radius), and the internal pressure of bubbles is mainly proportional to the surface tension of molten glass and inversely proportional to bubble radius. This shows that when the bubble is small and the surface of molten glass is large, the pressure inside the bubble is large and the gas in the bubble can be absorbed (dissolved). Based on the above two formulas, it can be seen that the surface tension of glass-ceramics will be the main factor affecting the sintering degree (shrinkage, which will affect the porosity) and the ability of internal bubbles to be absorbed (dissolved). Of course, viscosity is also an important factor affecting the sintering degree of glass-ceramics.
If the glass-ceramic composite plate undergoes glass-ceramization during the firing process
In the molten state, the influence of glass-ceramic particle size becomes less important.
These conclusions point out the direction for solving the technical problem of air holes in the first generation of glass-ceramics. For this reason, we introduced a lot of zinc oxide with high surface tension and low viscosity, successfully developed the second generation of glass-ceramics composite plate with wurtzite as microcrystalline phase, and put it into trial production in 2004 ~ 2005. At the same time, it also obtained the national invention patent.
Because the second generation of glass-ceramics has large surface tension and low viscosity, in the melting stage of glass-ceramics sintered by composite plate, the accumulated gaps between the original glass particles gather into larger bubbles and break through the surface. After the bubble bursts, the melt flows back and tears the interface constantly, which provides the lowest energy barrier position conducive to crystal growth and forms a variety of crystal forms, such as flower-like, chrysanthemum-like, radial, flowing, volcanic lava, etc. This reflects the crystallization characteristics of the second-generation glass-ceramics, that is, breaking through the grain boundaries of the first-generation glass-ceramics, and growing beautiful, natural, smooth and changeable crystal patterns again, thus greatly improving the aesthetics of its decorative art. In addition, due to the influence of the surface tension and viscosity of the second-generation glass-ceramics, the entire cross section of the glass-ceramics layer can basically have no gaps, only traces left by residual gas escaping from the surface (such traces will generally be eliminated after polishing). This is in sharp contrast to the first generation of glass-ceramics which left many pores in the cross section. These two characteristics are the advantages of the second generation glass-ceramics. However, the hardness and chemical resistance of the second generation glass-ceramics are lower than those of the first generation glass-ceramics, which is the disadvantage of the second generation glass-ceramics.
Since the second half of 2005, the price of 99.5% zinc oxide has risen sharply, from about 6,000 yuan per ton to 28,000 yuan per ton in the first half of 2006. Under the pressure of this economic situation, researchers turned to research and develop new glass ceramics, which are not as cheap as zinc oxide.
At the end of 2006, the third-generation glass-ceramic composite plate with pyroxene as microcrystalline phase was successfully developed, which not only did not add zinc oxide, but also greatly reduced the cost level of the second-generation glass-ceramics, while retaining the characteristics that the second-generation glass-ceramic crystals broke through the grain boundaries, grew different shapes of patterns and sections, and basically had no pores. The microcrystalline phase of glass-ceramics and pyroxene mainly belongs to clinopyroxene.
It is not difficult to see that clinopyroxene is a complex isomorphic mixture. According to the mineralogical properties of pyroxene, its Mohs hardness is 5.5 ~ 6.0 (4.5 ~ 5.0 for wollastonite and 5 ~ 5.5 for wurtzite), and it is insoluble in acid (wollastonite and wurtzite are soluble in hydrochloric acid).
Therefore, relatively speaking, the third-generation glass-ceramics have better mechanical properties and chemical corrosion resistance than the second-generation glass-ceramics. After more than one year's trial production, Xinzhongyuan Group and Bode Seiko Building Materials Co., Ltd. have successively realized the normal production of the third generation glass-ceramic composite board.
In 2008, Bode Company obtained an upgraded version of the third generation glass-ceramics through continuous in-depth research and special formulation system to control the growth of grains. This edition has unique decorative patterns, strong three-dimensional sense, realistic stone texture and soft color like water. It was the most artistic glass-ceramic composite board at that time, and was called the fourth generation glass-ceramic composite board.
It is also worth pointing out that New Zhongyuan Group and Bode Company have developed the fifth generation of glass-ceramic composite plates by using modern distribution methods such as template cloth, screen cloth and magic color cloth, as well as the interaction, diffusion and infiltration of different types and sizes of glass-ceramics. The layout of this composite board has ever-changing magic color effect and misty stripes. The colors that set off each other and the layered feeling like mountains have formed various abstract art scrolls and natural and realistic stone effects, realizing a gradual leap from architectural decoration materials to works of art.
In addition to various types of plane compounding, Bode Company has also realized three-dimensional compounding of large particles (up to several centimeters) of different glass-ceramics combinations, particles of glass-ceramics and ceramic powders, and particles of different ceramic powders (including translucent low-temperature materials), forming a patented product "Golden Diamond and Jade Steel". Of course, during this period, other manufacturers also carried out research and development. For example, Xinzhongyuan uses the mixing technology of glass particles and ceramic pigments to develop colorful composite plates; Oushennuo developed a unique glass-ceramic composite plate by using the composite technology of calendered glass plate and ceramic plate; Jiajun company developed "underglaze color" composite board by using screen technology and transparent glass. These advances have also played a certain role in promoting the development of glass-ceramics industry.
After 2009, microcrystalline stone has developed rapidly in China, especially 20 10, 201,20 12, and a series of microcrystalline stone products have been developed and produced by large ceramic enterprises. Since 20 1 1, a number of enterprises, such as Bode, Jiajun, Dong Peng and Oushennuo, have been exploring microcrystalline technology, and the technology is becoming more mature and the products are more refined. Take 20 1 1 as an example. According to incomplete statistics, in addition to Bode and Jiajun, which mainly produced microcrystalline products earlier, some enterprises mainly engaged in polished tiles and antique tiles have entered the microcrystalline field, such as Dong Peng, Eagle Brand, Kelpolo, Guanzhu, Xinghui, Oushennuo, Bohua, Xinzhongyuan and Maji. In Shandong and other producing areas, fewer enterprises have started to produce microcrystalline stone, and many first-line brands are increasing their investment in microcrystalline stone. In 20 13, a dark horse of Xiangcheng tiles in the United States also rose rapidly and became a new star in the success field, attracting much attention. Therefore, microcrystalline stone is regarded as another market explosion point after polished tiles, antique tiles and other categories.