Physical and chemical properties of silicon nitride:
The formula is Si3N4, the molecular weight is 140.28, according to the weight percentage, of which silicon accounts for 60.06%, nitrogen accounts for 39.94%. The two elements are electronegative and belong to strong covalent bond compounds (ion bonds account for only 30%). The color is gray, white or gray. Six party crystal system. The crystal is hexahedron. Density 3.44. Hardness is 9~9.5, Knoop hardness is about 2200, microhardness is 32630MPa. Melting point 1900 DEG C (under pressure). Usually decomposed at 1900 DEG C at atmospheric pressure. Specific heat capacity is 0.71J/ (g = K). The heat of formation is -751.57kJ/mol. The thermal conductivity is 16.7W/ (M = K). The coefficient of linear expansion is 2.75 * 10-6/ DEG C (20~1000 DEG C). Insoluble in water. Dissolved in hydrofluoric acid. The temperature at which air begins to oxidize in the air is 1300~1400 degrees centigrade. The specific volume resistance is 1.4 * 105. M at 20 degrees centigrade and 4 * 108. M at 500. The elastic modulus is 28420~46060MPa. The compressive strength is 490MPa (reactive sintering). 1285, when reacting with two nitride two calcium reacts to form two nitrogen calcium silicide, 600 degrees when the transition metal reduction, release nitrogen oxides. The flexural strength is 147MPa. It can be prepared by heating silicon powder in nitrogen or reacting silicon halide with ammonia. Silicon nitride has the advantages of high hardness, high melting point, stable structure, good insulation and wear resistance. Besides hydrofluoric acid, it does not react with other inorganic acids, has strong corrosion resistance, and resists oxidation at high temperature.
Silicon nitride and its deep processing products belong to the high-tech materials encouraged and supported by the state industrial policies.
Silicon nitride products have the following characteristics: saving resources, non polluting production process, technology and capital intensive high value-added new material products.
Production and use of silicon nitride:
Silicon nitride is grayish white, advanced inorganic non-metallic materials, has a very good application in steel smelting, refractory material, etc., at room temperature and high temperature resistant rubber, plastics, ceramics and other abrasive sealing is also widely used.
1, the main features. This product is a new type of material produced at a specific atmosphere and temperature. Main features: first, it has good corrosion resistance, thermal conductivity, thermal shock resistance and wear resistance. It can be used at temperatures below 1800 degrees celsius. Two, it has excellent splitting endurance, very stable chemical composition and thermal conductivity. Three, it has the advantages of small expansion coefficient, high thermal conductivity and high strength. Four is high temperature, good oxidation resistance.
2, advanced production technology. Silicon nitride production in our company adopts the international leading production technology to realize batch stable production, and can supply the goods at low price and high quality for a long time.
3, product wide range of uses. Silicon nitride powder is widely used in ceramics, refractory, iron and steel, metallurgy, nonferrous metallurgy and rubber industry as a new type of material for modern industry. Such as:
1) in the nonferrous metals industry, its corrosion resistance and erosion performance are excellent, and have been widely used.
2) in the iron and steel industry,
A and silicon nitride coating can effectively solve the problem of oxidation and burning loss in the process of billet heat treatment. The experimental results show that the nano silicate antioxidant coating and anti oxidation effect, oxide skin can make the original ordinary hot-rolled plate produced by 3%-5% to 0.1%-0.8%, the oxide skin of stainless steel hot rolled plate produced by 1%-3% below 0.2%.
B and silicon nitride stemming. Containing silicon nitride stemming, will play the role of effective sintering activation, corrosion resistance and anti disruptive effect on the furnace or electric furnace can be used in the blast furnace mouth more stable sealed, and very easy to cut.
C and silicon nitride have good applications in HRB400 high strength hot rolled steel bars. As a nitrogen increasing agent, Si3N4 is used in the production of V micro alloying, and the reinforcing bars of FeV are of good quality and stability. It is a new alloying process for the production of HRB400 grade III steel bars.
D and silicon nitride are second only to boron nitride in per unit mass nitrogen content, which have lower price and high cost performance in terms of nitrogen addition.
3) because this product has a good application in new ceramic and composite material, it can improve its corrosion resistance, thermal conductivity, thermal shock resistance, wear resistance and high strength.
4 、 chemical properties in use. Silicon nitride has very high temperature stability. Under acidic conditions, it has a high degree of corrosion resistance. At a temperature of 500 degrees Celsius, there is a high degree of alkaline resistance.
QQ screenshot 20161126143131.png
Note: 10-100mm, 0-200 mesh size, granule and powder can be produced according to user's requirement.
.
