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515825903931

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[交流] 100金币求助钡铁氧体方面摘要翻译

共四段（最后一段很少，忽略不计），每段20个金币，如果能全文翻译是100个金币。
谢谢各位大侠！
自蔓延燃烧合成钡铁氧体研究
摘要:磁铅石型(M型)钡铁氧体(BaFe12O19)由于具有原料便宜、化学稳定性优异、具有较高的矫顽力和磁能积、单轴磁晶各向异性和化学稳定性优异等优点，因而被广泛用作微波毫米波段材料、微波吸收材料和高密度垂直磁记录介质等。
本文采用自蔓延高温合成(SHS)和自蔓延低温合成(LCS)两种化学方法合成了磁铅石型钡铁氧体。自蔓延高温合成中，研究了铁粉含量、压制密度、钡源取代、掺镧、磁场激发对SHS的影响。自蔓延低温合成中，研究了烧结温度、溶胶pH、柠檬酸与金属离子摩尔配比、以及表面活性剂对LCS的影响。采用XRD、SEM、VSM对钡铁氧体的物相组成、显微结构及磁性能进行了表征。研究发现，用自蔓延高温合成法和自蔓延低温合成法都可以制备M型钡铁氧体。
在SHS中，铁粉含量对样品的磁性能影响较大，当铁粉的质量百分含量为25.74%时制备的粉体磁性最佳，其矫顽力为644.8Oe，饱和磁化强度(Ms)为26.26 emu/g，剩余磁化强度(Mr)为7.292emu/g，当铁粉的质量百分含量超过25.74%时，其饱和磁化强度、剩余磁化强度和矫顽力均迅速较小。此外，用BaO比BaCO3对BaO2进行取代是可行的。BaO比BaCO3取代效果要好。若要对BaO2进行取代，需要给反应提供额外的氧氛。SHS中钡铁氧体的压制密度也存在最佳密度值，为1.888 g/cm3。掺镧可以明显改变钡铁氧体的磁学性能, 当La3+离子的取代量为x=0.3时，钡铁氧体具有最佳的综合磁性能。
外加磁场条件下SHS合成BaFe12O19是可行的。磁场强度的增加利于提高BaFe12O19的磁性能。不同的磁化程度对产品的相组成和磁性能都产生了一定的影响。并且，磁场对SHS合成起主要作用的时期为铁氧体自蔓延燃烧时期。磁场强度为20T时，BaFe12O19磁性能与磁场方向的关系为：正向磁场﹥垂直磁场﹥反向磁场。
在LCS中，烧结温度对样品的磁性能影响较大，随着烧结温度的升高，样品的磁性能也随之提高，在900℃时内禀矫顽力出现最大值5.509kOe，1000℃时饱和磁化强度(Ms)，剩余磁化强度(Mr)出现最大值分别为59.84emu/g和31.99emu/g，当烧结温度超过1000℃时，其饱和磁化强度、剩余磁化强度和矫顽力均迅速较小。LCS合成钡铁氧体的最佳工艺条件为：前躯体溶液pH值为7.00，柠檬酸与金属离子的物质的量之比为2：1，自蔓延燃烧后的粉体在烧结温度为1180℃进行煅烧。适当的加入表面活性剂能提高其性能。
通过两种方法的对比分析，用自蔓延低温燃烧合成法制备出的粉末粒径更小，分布更均匀，磁性也更好。自蔓延低温合成更具有发展前景。

关键词：BaFe12O19，自蔓延高温合成，自蔓延低温合成，磁性能，磁场

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1楼 2009-04-22 12:51:13

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wwjlf

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Study on Self-propagating combustion synthesis barium ferrite

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515825903931(金币+20,VIP+0):谢谢您的帮忙，但是经过对比楼下的药更加准确、合理。 4-22 17:48

Abstract: The magnetic lead-type (M type) barium ferrite (BaFe12O19) due to cheaper raw materials, excellent chemical stability, high coercivity and energy product, uniaxial magnetic anisotropy and good chemical stability etc., which are widely used as a millimeter-band microwave materials, microwave absorbing materials and high-density perpendicular magnetic recording media.

In this paper, self-propagating high-temperature synthesis (SHS) and self-propagating high temperature synthesis (LCS) of two chemically synthesized magnetic-type barium ferrite lead. Self-propagating high-temperature synthesis, the study of the iron content, to suppress the density of the source replace the barium, lanthanum-doped magnetic field to stimulate the effects of SHS.Self-propagating high temperature synthesis to study the sintering temperature, sol pH, metal ions and citric acid molar ratio, as well as surfactants on the impact of LCS. Using XRD, SEM, VSM on the barium ferrite phase composition, microstructure and magnetic properties were characterized. The study found that use of self-propagating high temperature synthesis and self-propagating high temperature synthesis can be prepared M-type barium ferrite.

In the SHS, the iron content on the magnetic properties of samples a greater impact when the quality of iron content of 25.74% per cent when the magnetic powder prepared by the best, the coercivity for 644.8Oe, saturation magnetization (Ms) to 26.26 emu / g, residual magnetization (Mr) for 7.292emu / g, when the quality of iron concentration of more than 25.74% percent, the saturation magnetization, residual magnetization and coercivity are small quickly.In addition, the use of BaCO3 to BaO than to replace BaO2 is feasible. Replace the effect of BaO is better than the BaCO3. To BaO2 to replace the need to respond to provide additional oxygen atmosphere. SHS in the suppression of the density of barium ferrite, there are also the best density for the 1.888 g/cm3. Lanthanum-doped barium ferrite can be significant changes in the magnetic properties, when the La3 + ions replace the capacity of x = 0.3, the barium ferrite integrated with the best magnetic properties.

External magnetic field under the conditions of SHS Synthesis BaFe12O19 is feasible. The increase in magnetic field strength BaFe12O19 help improve the magnetic properties. Degree of magnetization different products with the composition and magnetic properties have had a certain impact. In addition, magnetic field on the SHS synthesis play a major role in the ferrite during the period of self-propagating combustion.20T when the magnetic field strength, BaFe12O19 magnetic field direction with the relationship: a positive magnetic field> vertical magnetic field> magnetic field reverse.

In the LCS, the sintering temperature on the magnetic properties of samples can affect the larger, with the sintering temperature, the magnetic properties of the samples also increased, at 900 ℃ Hcj maximum appears 5.509kOe, 1000 ℃ when saturation magnetization (Ms), residual magnetization (Mr) there were maximum 59.84emu / g and 31.99emu / g, when the sintering temperature is above 1000 ℃, the saturation magnetization, residual magnetization and coercivity are small quickly. Synthesis of barium ferrite LCS the best conditions were as follows: pre-body solution pH value of 7.00, citric acid and metal ions in the volume of the material ratio of 2:1, since the spread of the powder in the post-combustion temperature of 1180 ℃ sintering for calcination. The addition of appropriate surfactants can enhance performance.

Through comparative analysis of two methods, using low-temperature self-propagating combustion synthesis of the powder prepared by a smaller particle size distribution more uniform and better magnetic properties. Self-propagating high temperature synthesis of more prospects for development.

Key words: BaFe12O19, SHS, self-propagating high temperature synthesis, magnetic properties, magnetic field

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2楼2009-04-22 13:31:50

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zhaomei2007

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515825903931(金币+80,VIP+0):谢谢 4-22 17:48

Study on the Synthesis of Barium Ferrite with Self-Propagating Combustion Technology

Abstract: Magnetic lead-type (M type) barium ferrite (BaFe12O19) is widely used as millimeter-band microwave materials, microwave absorbing materials and high-density perpendicular magnetic recording medias for its superior advantage in terms of lower prices of raw material, excellent chemical stability, higher coercivity and energy product as well as its uniaxial magnetic anisotropy etc.

  In this paper, Magnetic lead-type barium ferrite was synthesized with two different approaches respectively, namely self-propagating high-temperature synthesis (SHS) and self-propagating low temperature synthesis (LCS). In terms of SHS, the influence of the iron content, pressing density, replacement of the barium, doped lanthanum as well as magnetic field inspiration on SHS were investigated. In terms of LCS, the influence of sintering temperature, sol pH, molar ratio of citric acid to metal ions as well as surfactants on LCS were investigated, respectively. The barium ferrite phase composition, microstructure and magnetic properties were also characterized with the help of XRD, SEM, VSM. Our study showed that both of the two approaches could be used in preparing M-type barium ferrite effectively.

  In the study of SHS, the iron powder content had a  relatively closer connection with the magnetic properties of samples. As an example, magnetic properties of barium ferrite reached the optimal point when iron mass fraction was 25.74%, in which condition the coercivity was 644.8Oe, saturated magnetization (Ms) was 26.26emu/g, residual magnetization (Mr) was 7.292emu / g, respectively. However, once the iron mass fraction exceeded 25.74%, coercivity, Ms and Mr would drop significantly. In addition, the replacement of BaO2 with BaO was better than with BaCO3, as the replaceing effect of the former was superior to the latter. To replace BaO2, extra oxygen was needed. The pressing density in barium ferrite also had an optimal value of 1.888 g/cm3. Doped lanthanum could obviously change the magnetic properties of barium ferrite and barium ferrite exhibited the best comprehensive magnetic properties when the replacing capacity of La3+ was 0.3.

  It was possible to synthesize BaFe12O19 with the help of SHS under external magnetic field conditions, and the increase of magnetic field strength would be helpful for the improvement of magnetic properties. Degree of magnetization would exert certain influence on the composition and magnetic properties of the final products. Moreover, the crucial period that magnetic field played its role in SHS synthesis was during the course of self-propagating combustion. When magnetic field strength was 20T, the relationship between magnetic properties of BaFe12O19 and magnetic field direction was shown as follows: positive magnetic field> vertical magnetic field> reverse magnetic field.

  In the study of LCS, sintering temperature had a major impact on the magnetic properties of samples. And with the increase of sintering temperature, magnetic properties were improved accordingly. Coercivity reached its maximum of 5.509kOe at 900℃, while Ms and Mr both reached their maximum of 59.84emu/g and 31.99emu/g at 1000℃, respectively. When the sintering temperature exceeded 1000℃, coercivity, Ms and Mr dropped significantly. The optimal conditions of the synthesis of barium ferrite with LCS approach were shown as follows: pH of former solution was 7.00; ratio of citric acid to metal ions was 2：1; sintering temperature was 1180℃. Addition of appropriate surfactants could also help enhance the magnetic properties.

  In comparison with SHS, barium ferrite powder characterized by a smaller particle size, uniform distribution and better magnetic properties could be prepared with LCS. To sum up, synthesis of barium ferrite with LCS technology had a broad prospect.

Key words: BaFe12O19, self-propagating high temperature synthesis, self-propagating low temperature synthesis, magnetic properties, magnetic field