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The time temperature transformation (TTT) diagrams of fluoride free mold fluxes containing TiO2/ZrO2 were constructed through the confocal scanning laser microscope (CSLM) technique. It was found that the crystallization temperature of F free mold fluxes containing TiO2 or ZrO2 increases, while incubation time decreases with increasing basicity. The crystallization tendency increases with the zirconia addition in slag melt, as it may be thought that the addition solubility is limited in molten slag and the solid particles act as heterogeneous nucleation sites. Three types of crystal morphologies were observed, corresponding to different crystallization mechanisms. CaSiO3 and Ca3Si2O7 precipitate in the slag with low basicity, and Ca2SiO4 was formed with increasing basicity. The addition of TiO2 promotes the precipitation of CaTiO3. The logarithm of crystal growth rate increased with increasing isothermal temperature, suggesting that the crystal/melt interface reaction is the controlling step in the present experiment. 相似文献
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结晶器含钛无氟保护渣的粘度和熔化特性 总被引:4,自引:0,他引:4
以CaO-SiO2-TiO2渣系为基础配制了含钛无氟结晶器保护渣,为建立和优化配置规律,通过实验测定熔渣的粘度和熔点,研究了含钛无氟保护渣熔化特性与助熔剂、TiO2含量及二元碱度之间的关系。结果表明:B2O3和碱金属Na2O、Li2O均能有效降低粘度和熔点,其中以B2O3作用最为明显;TiO2含量为6%时,粘度和熔点均呈最小值。在4%~10%范围内,MgO可降低粘度,但会使熔点升高;含量<3%时,MnO可降低粘度,含量超过5%则会同时使粘度和熔点增加。 相似文献
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以合金Ti-x Nb(x=30%~70%)为基底,硝酸为电解液,采用超快阳极氧化制备出了复合纳米多孔氧化膜。通过XRD、SEM和TEM等测试技术对所制备的复合纳米多孔氧化膜进行表征,发现氧化膜的表面孔径为10~30 nm,膜背面的孔径为20~60 nm,且纳米孔的孔间距随着Nb含量和电解液浓度的增加而增大。氧化膜的生长速度30μm/h。氧化薄膜的形成与硝酸的强氧化性活化了金属表面有关。氧化膜贯穿的原因可能是由于覆盖合金表面的纳米多孔氧化物薄膜产生的压应力和极化、浓度及温度梯度所产生的拉应力,两者之间的相互作用造成的氧化膜的自剥离。 相似文献
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Physical Properties and Regulating Mechanism of Fluoride-Free and Harmless B2O3 -Containing Mould Flux 总被引:1,自引:0,他引:1
There were certain amounts of CaF2, NaF orNa2Oin traditional mould fluxes ai ming to modifythe melting property of mould fluxes[1 -5], whichwould do great harmto the service performance ofmould fluxes . Meanwhile the environment was pol-luted seriously and health of operators was i mpairedheavily .Calciumfluorideledtothe separating out ofhigh melting point substance as spars , which de-stroyed the glass properties of mould fluxes .If flu-oride-containing mould fluxes entered the coolingwater… 相似文献
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