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过两级还原退火转变为Nd Fe B磁粉,通过800℃的一级还原退火使Nd Fe B中间体转化成NdFeO3,B2O3,Nd2O3和α-Fe相;二级还原退火在Ca H2辅助下的反应过程:首先B2O3在501℃下被还原成B相,接着678℃时,Nd2O3和Nd Fe O3被还原以形成α-Fe和Nd H2相,最后895℃时,B,Nd H2和α-Fe发生合金化反应形成Nd2Fe14B磁粉.关键......
to the interface of the slag and silicon,or B2O3 formed by the chemical reaction diffuses from the slag–silicon interface to molten slag.关键词:......
缓阶段主要是由于氧化产物B2O3与H2O反应生成了挥发性产物.随着温度的升高,两反应阶段试样的质量增加率均有所提高.利用周模型对BN材料在高温含水条件下的反应动力学进行了较为精确且定量的拟合,结果与实验数据吻合良好.关键词:陶瓷材料;氮化硼;粉体;水蒸气;反应动力学;......
NaCl加入量对自蔓延高温燃烧合成法大规模制备的超细二硼化钛粉体性能的影响(英文)喇培清1,欧玉静2,韩少博1,卢学峰1,魏玉鹏11. 兰州理工大学省部共建有色金属先进加工与再利用国家重点实验室2. 兰州理工大学石油化工学院摘 要:以TiO2,B2O3,Mg粉为原料,引入稀释剂NaCl,通过自蔓延高温燃烧合成法宏量制备了亚微米TiB2粉体,并对其进行了SEM(扫描电镜),EDS(能谱),XRD(X射线衍射)和粒度分析.用原子吸收光谱测定了浸出产物TiB2粉体中杂质Mg,O的含量.结果表明:稀释剂加入量对样品......
再论载体材料与贵金属催化剂--粉末冶金多孔金属应当是贵金属催化剂的合理载体材料金家敏,包伟芳上海材料研究所摘 要:理论分析和实验结果表明催化过程中催化剂不参加化学反应,催化剂本身不发生化学变化,化学反应模式催化循环反应不可能发生,1902年提出的化学反应模式的催化循环原理(Sabatier’s principle and Boudar’ts prin-ciple)难以令人信服.简述了触媒理论的逻辑推理及实验验证.触媒理论认为催化循环是催化剂质点内运动的电子轨道变形与恢复的循环,催化剂(或促进剂)有助于变形了......
Sintering Behavior and Microwave Dielectric Properties of MgTiO3 Ceramics Doped with B2O3 by Sol-Gel MethodHuanping Wang, Qinghua Yang, Denghao Li, Lihui Huang, Shilong Zhao and Shiqing Xu College... properties due to the pores in the ceramics. The addition of B2O3 used as a liquid sintering aid reduced the sintering temperature of MgTiO3 ceramic, which was supposed to enter the MgTiO3 lattice......
Kinetics of fluorescence properties of Eu3+ ion in strontium-aluminiumbismuth-borate glassesM.Dhamodhara Naidu,D.Rajesh,A.Balakrishna,Y.C.RatnakaramDepartment of Physics, Sri Venkateswara University摘 要:Eu3+ doped strontium-aluminium-bismuth-borate glasses with the chemical composition(50–x)B2O3+20Bi2O3+7Al F3+ 8Sr O+15Sr F2+x Eu2O3(where x=0.1 mol......
Kinetics of fluorescence properties of Eu3+ ion in strontium-aluminiumbismuth-borate glassesM.Dhamodhara Naidu,D.Rajesh,A.Balakrishna,Y.C.RatnakaramDepartment of Physics, Sri Venkateswara University摘 要:Eu3+ doped strontium-aluminium-bismuth-borate glasses with the chemical composition(50–x)B2O3+20Bi2O3+7Al F3+ 8Sr O+15Sr F2+x Eu2O3(where x=0.1 mol......
, WU G H, DING W J, ZHU Y P. Study on Fe reduction in AZ91 melt by B2O3 [J]. Materials Science and Engineering A, 2004, 368(1/2): 530-536. [14] RAVI K R, PILLAI R M, AMARANATHAN K R, PAI B C, [9] CHENG......