正在加载图片...
.376 北京科技大学学报 第29卷 假定图2C~G中过渡结构出现的衍射斑点是 矿向金属铁转变过程中出现的过渡结构，从C点到 钛铁矿到金属铁还原过程晶格膨胀或收缩引起的， G点其晶胞常数的变化逐渐偏离钛铁矿的晶胞常 分别通过式(1)~(4)按钛铁矿和金属铁的衍射晶面 数，而接近金属铁的单胞常数，这与钛铁矿到金属铁 来计算，推算晶体转变过程中钛铁矿和金属铁晶格 还原的过程是一致的，因此，可以认为钛铁矿到金 常数变化，如表1所示，从表1可以看出，对于钛铁 属铁的结构转变是一个渐变过程， 表1按钛铁矿和金属铁计算的过渡结构的晶胞常数 Table 1 Lattice parameters of transition structure calculated according to the diffraction patterns of ilmenite or iron nm 已确定的物相 过渡结构 位置 钛铁矿 金属铁 按钛铁矿计算的结果 按金属铁计算的结果 B a=0.50884,c=1.40930 C a=0.50884,c=1.40930 a=0.34368,c=0.74392 a=0.24463 D a=0.50884,c=1.40930 a=0.34368,c=0.74392 a=0.24463 E a=0.27883,c=0.96307 a=0.22149 F 、 a=0.28487,c=0.91988 a=0.22375 G a=0.28818 a=0.28933,c=0.88470 a=0.22607 H a=0.28664 in iron oxides.Mater Sci Forum,1996,207/209(1):369 3 结论 [4]Watanabe Y,Ishii K,Ishikawa N.et al.In situ observation of transformation in a Fe203 under hydrogen implantation.J Phys (1)[110]方向的金属铁晶体在[1431]方向的 Condens Matter,2002,14(49).13643 钛铁矿晶体上生成； [5]Katsumi M.Tamura Y.Kashiwaya Y,et al.TEM observation of magnetite and wustite implanted with hydrogen//Proceedings of (2)钛铁矿还原过程中，金属铁的(222)或 the Sixth International Iron and Steel Congress.Nagoya.1990. 50 (222)晶面优先由钛铁矿的(4264)或(4264)晶面转 [6]Makhlij N A,Kovalenko AA.Tsvetkov Y V.Reduction of sur- 变而来； face layers of magnetite single crystals by accelerated hydrogen (③)钛铁矿还原到铁的结构变化是一个渐变过程. ions.Fiz Khim Obrab Mater,1995(5):103 [7]Guo X M.Sasaki Y,Kashiwaya Y,et al.Microreaction mecha- 参考文献 nism in reduction of magnetite to wustite.Metall Mater Trans. 2004,35B(3):517 [1]Porter J R.Swann P R.High voltage microscopy of reduction of [8]Wechsler B A,Prewitt C T.Crystal structure of ilmenite (Fe- hematite to magnetite.Ironmaking Steelmaking.1977.4(5): TiO3)at high temperature and at high pressure.Am Miner, 300 1984,69(1/2):176 [2] Watanabe Y,Takemura S,Kashiwaya Y,et al.Reduction of [9]Wilson N C.Muscat J.Mkhonto D.et al.Structure and proper- haematite to magnetite induced by hydrogen ion implantation.J ties of imenite from first principles.Phys Rev B.2005,71(7):1 Phys D,1996,29(1):8 [10]Adachi H.Kowada Y.Tanaka I.et al.Elementary calculation [3] Watanabe Y.Ishii K.Orientation relationships and transformation for electron state.Tokyo:Sankyo Press,1999,67 Microreaction mechanism of the reduction of ilmenite to iron by H2 ion implanta- tion DAI Yunduo,GUO Xingmin,ZHANG Jiayun Metallurgical and Ecological Engineering School.University of Science and Technology Beijing.Beijing 100083.China ABSTRACI H2 ions were implanted into ilmenite at room temperature,and the microreaction mechanism dur- ing the reduction of ilmenite was investigated by transmission electron microscopy.The results indicate that dur ing the course of reduction,metallic iron with [110]orientation is formed on ilmenite along [1431]direction. (222)or (222)plane of iron is transformed from (4264)or (4264)plane of ilmenite firstly.The structure change during the course of reduction from ilmenite to iron is a gradually changing process. KEY WORDS ilmenite;hydrogen ion implantation;reduction process;microreaction;microstructure change假定图2C～G 中过渡结构出现的衍射斑点是 钛铁矿到金属铁还原过程晶格膨胀或收缩引起的 分别通过式（1）～（4）按钛铁矿和金属铁的衍射晶面 来计算推算晶体转变过程中钛铁矿和金属铁晶格 常数变化如表1所示．从表1可以看出对于钛铁 矿向金属铁转变过程中出现的过渡结构从 C 点到 G 点其晶胞常数的变化逐渐偏离钛铁矿的晶胞常 数而接近金属铁的单胞常数这与钛铁矿到金属铁 还原的过程是一致的．因此可以认为钛铁矿到金 属铁的结构转变是一个渐变过程． 表1 按钛铁矿和金属铁计算的过渡结构的晶胞常数 Table1 Lattice parameters of transition structure calculated according to the diffraction patterns of ilmenite or iron nm 位置 已确定的物相 过渡结构 钛铁矿 金属铁 按钛铁矿计算的结果 按金属铁计算的结果 B a＝0∙50884c＝1∙40930 － － － C a＝0∙50884c＝1∙40930 － a＝0∙34368c＝0∙74392 a＝0∙24463 D a＝0∙50884c＝1∙40930 － a＝0∙34368c＝0∙74392 a＝0∙24463 E － － a＝0∙27883c＝0∙96307 a＝0∙22149 F － － a＝0∙28487c＝0∙91988 a＝0∙22375 G － a＝0∙28818 a＝0∙28933c＝0∙88470 a＝0∙22607 H － a＝0∙28664 － － 3 结论 （1） ［1 － 10］方向的金属铁晶体在［1 － 43 － 1］方向的 钛铁矿晶体上生成； （2） 钛铁矿还原过程中金属铁的（2 － 2 － 2 － ）或 （222）晶面优先由钛铁矿的（426 － 4 － ）或（4 － 2 － 64）晶面转 变而来； （3） 钛铁矿还原到铁的结构变化是一个渐变过程． 参 考 文 献 ［1］ Porter J RSwann P R．High-voltage microscopy of reduction of hematite to magnetite．Ironmaking Steelmaking19774（5）： 300 ［2］ Watanabe YTakemura SKashiwaya Yet al．Reduction of haematite to magnetite induced by hydrogen ion implantation．J Phys D199629（1）：8 ［3］ Watanabe YIshii K．Orientation relationships and transformation in iron oxides．Mater Sci Forum1996207／209（1）：369 ［4］ Watanabe YIshii KIshikawa Net al．In situ observation of transformation in α－Fe2O3 under hydrogen implantation．J Phys Condens Matter200214（49）：13643 ［5］ Katsumi MTamura YKashiwaya Yet al．TEM observation of magnetite and wustite implanted with hydrogen∥Proceedings of the Sixth International Iron and Steel Congress．Nagoya1990： 50 ［6］ Makhlij N AKovalenko A ATsvetkov Y V．Reduction of surface layers of magnetite single crystals by accelerated hydrogen ions．Fiz Khim Obrab Mater1995（5）：103 ［7］ Guo X MSasaki YKashiwaya Yet al．Microreaction mechanism in reduction of magnetite to wustite．Metall Mater Trans 200435B（3）：517 ［8］ Wechsler B APrewitt C T．Crystal structure of ilmenite （FeTiO3） at high temperature and at high pressure．Am Miner 198469（1／2）：176 ［9］ Wilson N CMuscat JMkhonto Det al．Structure and properties of ilmenite from first principles．Phys Rev B200571（7）：1 ［10］ Adachi HKowada YTanaka Iet al．Elementary calculation for electron state．Tokyo：Sankyo Press1999：67 Microreaction mechanism of the reduction of ilmenite to iron by H ＋ 2 ion implantation DAI Y unduoGUO XingminZHA NG Jiayun Metallurgical and Ecological Engineering SchoolUniversity of Science and Technology BeijingBeijing100083China ABSTRACT H ＋ 2 ions were implanted into ilmenite at room temperatureand the microreaction mechanism during the reduction of ilmenite was investigated by transmission electron microscopy．The results indicate that during the course of reductionmetallic iron with ［1 － 10］ orientation is formed on ilmenite along ［1 － 43 － 1］ direction （222） or （2 － 2 － 2 － ） plane of iron is transformed from （426 － 4 － ） or （4 － 2 － 64） plane of ilmenite firstly．The structure change during the course of reduction from ilmenite to iron is a gradually changing process． KEY WORDS ilmenite；hydrogen ion implantation；reduction process；microreaction；microstructure change ·376· 北 京 科 技 大 学 学 报 第29卷