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Butterflies Eco-friendly ceramic mugs cups What is the impact |
| Ceramic Mug From:Xinxiang Ceramic Mug Manufacturers 2016-3-10 |
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Butterflies Eco-friendly ceramic mugs cups
The impact on the traditional ceramic firing atmosphere have the following main points:
(1) When the glaze firing or a firing temperature stage is added to coal or wood in a batch mode, the temperature in some venue, multi-line reduction, oxidation atmosphere alternating cycles. Following is balanced even if oil or gas is added, the kiln atmosphere may be more uniform and stable. But when asked to restore the role of a longer, no buffer zone, resulting in a relatively low concentration of the reducing agent. Also to be considered as well as the exclusion of water vapor and CO2 required H2 / H20 and CO / CO2 ratio of two.
(2) For the narrower firing porcelain, large changes in the volume of the heating phase, you should consider stepped jump circuitous warming, is divided into several small regions, each region of the insulation appropriate to extend asked of a larger contraction several smaller contraction in order to ease the body becomes concentrated phenomenon, the shrinkage becomes small, relatively slow down the speed of contraction. According kiln, the different sub-species loaded kiln kiln bit to take advantage of heat. Of course, there are some special circumstances electricity, must be treated differently. Such as: After some ceramics by reducing flame and high temperature re-burned, glazed blue and was beautiful piece pattern occurs, it is not only inadequate reduction, but also the firing temperature is not enough of the edge; a piece of Longquan Kiln porcelain brother try Fe2O3 samples containing up to 2.39%, TiO2 as a trace, preached white porcelain; in the iron content of about 1.5% of the blanks in the mud 1% of TiO2, after restore the flame burning, tire that is gray, not added TiO2 blank mud tires in the same situation continued to show white. Titanium visible impact in reducing flame coloring than the iron is strong. In addition, organic matter in the womb fails to burn off during firing, but also make tires gray. Jingdezhen region using local clay, a reducing atmosphere is heated to relatively lower the sintering temperature, porosity oxidizing atmosphere heated by 17.3% to 4.6%. At high temperature, O2, CO2, H20 and SO2 gas belonging oxidative atmosphere; CO, H2 and CH4 belonging to a reducing atmosphere; N2 is a neutral atmosphere. On traditional porcelain, the water vapor may glaze decomposition crystallization, volatile alkali and dull, even surface to form crust. Blank stack gas channel and should be conducive atmosphere circulation. Heating up too fast, the atmosphere is equivalent to lack of oxygen, the body easily lead to blank carbonized organic matter and bulging. Reduction of the free energy, such as C02 + C2CO, at a temperature of 978 when AGT0 = 0, below this temperature, CO readily precipitated product defects caused by C. SiO unstable, sometimes by decomposition 2SiOSi02 + Si, Si contaminate glazed porcelain.
Kiln firing atmosphere structure also has an adaptive problems. Intermittent kiln is based on "the firing curve for a time" approach to arrangement of the combustion chamber and exhaust holes to constitute the required heating gas into and out of the flame atmosphere variable depending on time; tunnel kiln is based on "the firing of a space curve." scheduled, each combustion chamber flame arrogance unchanged, with the body only by the speed of the combustion chamber arrangement carts natural place. Loseware and trolley speed must be full unity, a thermal oxidation-reduction ask each chamber must distance and the overall layout and structure appropriate arrangements to ensure that each section of the heating curve firing heat supply, conversion atmosphere, pressure adjustment, smoke gas discharge. In general, the reduction or not, the most important is to see whether the free oxygen in the presence of the kiln. This is more important than the content of CO medium. This is linked to the kiln member sealed to prevent overflow getter. First, the furnace should be reasonable, and the establishment of regular maintenance and repair system. Followed by combustion and burner power specifications to be supporting, not only by the burning heat density calculations, near the exit must consider the burner has compounded the concentration of carbonaceous substances and cleavage products to ensure the formation of a reducing atmosphere in the kiln long and soft soft fire.
The following give two specific examples to discuss restore the flame burning.
(1) blue enamel, the Department of CaO-K2O glaze, Song formerly belong CaO glaze systems. Fe2O3 content of about 2%. Longquan, officer, brother Zhu glaze kiln has dropped to 1.5%, Longquan powder blue, plum glazed and some fell below 1%. Mei Celadon firing high temperature, reducing atmosphere is heavy, improved glaze Fe2 + content, glaze trend Tsui. When the reduction ratio (FeO / Fe203) low dry 0.3 below, the nature of the reducing atmosphere tended to oxidation. If the firing temperature is high or low oxygen partial pressure, often transforming ferric to ferrous iron may occur. Most Fe2 + shade compounds may show absorption bands in the infrared region extending into the red zone results. Thus, celadon glaze was blue; white porcelain is slightly Fan Qing. Contact Tianmu rabbit hair glaze at (1332 20 ) certain reducing conditions in the iron oxide crystal phase after the film, the more to the formation of silver precipitates Fe204 Tuhao microcrystalline, also may be due to this.
(2) Glaze, scholars sometimes broadly certain iron-based glaze has a split-phase structure was placed in Tianmu range. Although at the time of different titles, such as the construction of light, Jizhou kiln, Shanxi droplets, Pengcheng kiln. In the meantime, construction lights, etc. are mostly (CAS2) Crystallization - (liquid-liquid) phase - (iron oxide) Crystallization glaze. Glaze Fe203 content is as follows: Jianyang Glaze (Tuhao lamp) 5.26 ~ 8.49%, fetal 7.07 ~ 9.65%, higher than the glaze, reducing atmosphere firing; Jizhou Glaze 4.31 ~ 6.66%, the oil droplets glaze 5-7%. Some scholars have made a more specialized discussion by experimental device, the formation mechanism and pointed out some trends. Mainly: iron affected by the atmosphere in the kiln glaze structure valence state and coordination number, and their concentration in the surface layer of the glaze distribution, crystallization and other iron compounds, together constitute Glaze black, blue, gray, iron red, reddish brown, brown and other various glaze.
In short, the glaze firing in a reducing atmosphere, reducing porosity, larger surface tension of the glaze, easy to form ferrous silicate, relatively lower firing temperature. Glazed achieve smooth, opaque, dense effect.
However, the reduction of certain ceramic materials firing atmosphere influence and role is quite complex. Related to gas-solid reaction, adsorption, dissolution, diffusion and a series of processes. Gas composition and nature of closed pores vary within the kiln atmosphere and different. Steam medium on MgO and CaO, UO2 and other general is to promote sintering, and the opposite of a cohesion mechanism of BeO evaporation control system due to the effect. Hydrogen atmosphere conducive sintered -A1203 material, and increase the bulk density, and transparent piezoelectric ceramic firing pressure ventilation is suitable to take at low partial pressure of N2. In short, the firing atmosphere in what is subject to the composition of porcelain blanks, additives, materials, performance requirements may be.
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