effect of microsilica on properties of aluminum-pg电玩城

  microsilica also known as silica fume, is formed by oxidation at a high temperature of 2000 degrees. the ultrafine high-purity amorphous silica was observed to have a spherical shape under an electron microscope, amorphous and amorphous, and an average particle diameter of 0.2 μm. it has excellent physical and chemical properties. the effect of microsilica on the performance of aluminum-magnesium spray feed: 

(1) the liquid phase is formed by the reaction of the added microsilica with al2o3, mgo and cao in the sample matrix at high temperature. therefore, the high-temperature flexural strength of the sample decreases as the amount of microsilica added increases. 

(2) the smaller the amount of microsilica is added, the smaller the permanent line change of the sample is. the sample with higher content of microsilica expands during the initial heating and shrinks in the subsequent heating, so cracks are more likely to occur. on the other hand, the sample having a lower content of microsilica, on the other hand, does not cause further permanent line change after the initial heating is expanded, so that it is difficult to form a crack. 

(3) the thermal shock cycle causes cracks inside the sample. therefore, as the number of thermal shock cycles increases, the elastic modulus of the sample gradually decreases. the content of microsilica powder is different, and the elastic modulus of the sample after thermal shock decreases. the amplitude is also different: the less the amount of microsilica is added, the less cracks are generated inside the sample, and the smaller the modulus of elasticity is, the better the thermal shock resistance is. 

(4) the smaller the amount of microsilica powder added, the less cracks are generated on the cross section of the sample, and the better the peeling resistance of the sample. on the other hand, the content of microsilica is high, and the sintering of the hot surface of the sample at high temperature causes the material to shrink. 

(5) the smaller the amount of microsilica added, the better the corrosion resistance of the castable. since there is no significant difference in the amount of penetration of the slag between the samples having different microsilica content, it is considered that the microsilica only reduces the melting temperature of the material and affects its corrosion resistance. 

  the main chemical composition of high-quality microsilica is sio2, the content can reach 85-95%, and its elements include fe2o3, al2o3, cao, k2o, na2o, mgo, c and so on. the microsilica has an average particle diameter of 0.1-0.15 μm, which is a few percent of the average particle size of the cement. it has a specific surface area of 15-27 m2/g and is extremely surface active. 

  therefore, it can be expected that the wet spray material having a lower content of micro silicon powder will exhibit better corrosion resistance and peeling resistance, thereby having a longer service life. effect of apparent porosity of chrome oxide aggregate on properties of high chromium oxide castables due to the excellent corrosion resistance of cr2o3 materials against molten slag, the application of cr2o3-al2o3 castables in waste incinerators is becoming more and more widespread. the corrosion resistance of castables increases with the increase of cr2o3 content, and the corrosion resistance of high cr2o3 castables has a certain relationship with the apparent porosity of cr2o3 aggregates.