Chang Hui , Zhou Lian , Zhang Tingjie
2007, 36(9):1505-1510.
Abstract:綜述了近年來國內外學者在鈦合金固態(tài)相變理論和實驗研究方面的進展情況,介紹了幾種鈦合金固態(tài)相變的研究實驗方法,并對鈦合金中馬氏體、硼、亞穩(wěn)腳分解等相變動力學、晶體學以及組織的演變、形核生長等進行了總結和歸納。
Jia Wanming , Zhang Quanxiao , Bai Zhiguo , Ma Shaohua , Yao Dong , Wang Yingqi
2007, 36(9):1511-1516.
Abstract:In this paper, the progresses on manufacturing and precision forming techniques home and overseas have been introduced for exact shaped charge liners in detail. Some trends of advanced manufacturing techniques for heavy metal liners have been also discussed and predicted for the future. It is considered that the material of liners is key to improve the penetrating properties of shaped charges, and the forming technology plays an important role in the jets characters, then influences the penetration effect for shaped charge liners.
Shen Jun , Pei Xinfeng , Peng Guilin , Fu Hengzhi
2007, 36(9):1517-1522.
Abstract:The effects of inductor structure, the positions of solid/liquid interface and melt top, and different alloys on the melt shape in electromagnetic contactless shaping process have been simulated by FEM method in the present paper. It is found that the inductor with an oblique inside wall makes the melt form an ideal vertical periphery. The position variation of solid/liquid interface and melt top can change the melt shape obviously. The electrical current frequency and the material kind have hardly effects on the melt shape. The experiment results have good agreements with the simulation results. Finally, some bars and plates of Al alloy, TiAl intermetallics and superalloy are produced in an unidirectional control of their structures by the contactless forming process.
Yu Zhongliang , Zhao Yongqing , Zhou Lian , Sun Jun , Qu Henglei
2007, 36(9):1523-1526.
Abstract:研究了缺口對TC21合金在不同溫度高周和低周疲勞強度的影響。疲勞試樣為光滑和V型缺口(Kt=3)2種試樣,疲勞載荷為應力控制,循環(huán)應力比為0.1,高周疲勞實驗溫度為315℃,低周疲勞實驗溫度為室溫及400℃。結果表明,在循環(huán)應力較低,缺口根部未塑性變形時,缺口使疲勞強度明顯降低。循環(huán)應力升高使缺口根部產生塑性變形時,缺口對疲勞強度影響降低,當循環(huán)應力升高使光滑試樣失穩(wěn)時,缺口試樣的疲勞強度高于光滑試樣的疲勞強度。斷口的SEM分析表明,缺口試樣的疲勞裂紋在缺口根部萌生,即使高周疲勞裂紋源也是多個。
Li Shuhua , Wang Fuchi , Tan Chengwen , Chen Zhiyong , Sun Zhi
2007, 36(9):1527-1529.
Abstract:Microstructural evolution of the adiabatic shear bands originated by the deformation of high strain for TA2 has been examined. Tests were performed using a specially designed stepped specimens in a Hopkinson bar. Upon completion of deformation, the region is cooled below half the temperature achieved during adiabatic heating for less than one millisecond. Microsturctural characterizations of shear bands were analysed using SEM, TEM and the TEM of high resolving power. No evidence of transition from a-Ti to another phases within the adiabatic shear bands could be found. However, the kinetics of boundary refinement processes were not taken into account in these studies with the distinctive characteristic of recrystallized microstructure. It is shown that there is no phase transformation in the TA2 adiabatic shear bands, which are composed of fine equiaxed grains. The dynamic recrystallization in the TA2 adiabatic shear bands was performed by the mixed mechanism of grain mechanical fragmentation, grain boundary transfer and subgrain roughen, and the recrystallization mechanism of progressive subgrain misorientation.
Shen Qianhong , Yang Hui , Gao Jiwei , Yang Jiegeng
2007, 36(9):1530-1533.
Abstract:采用浸漬提拉法依次在普通載玻片上制備PEDT/PSS(聚乙撐二氧噻吩(PEDT)摻雜聚苯乙烯磺酸鹽(PSS))薄膜層和TiO2薄膜層,從而獲得TiO2-PEDT/PSS雙層復合膜。考察了PEDT/PSS涂膜液的組成、PEDT/PSS薄膜層厚度以及Ti02薄膜層厚度對TiO2-PEDT/PSS復合膜光催化活性的影響。發(fā)現(xiàn)PEDT/PSS溶液與正硅酸乙酯(TEOS)水解產物的體積比為10:1~15:1時,PEDT/PSS涂膜液性能最優(yōu),PEDT/PSS薄膜層的最佳厚度為2μm,TiO2薄膜層的最佳厚度在200nm左右。此外,還對復合膜光催化活性提高的機制進行了探討。結果表明,由于PEDT/PSS的最低空余軌道的電位低于Ti02的導帶電位,紫外光照下,TiO2中產生的光生電子注入到PEDT/PSS層,有效抑制了電子.空穴對的復合,增加了復合膜表面空穴的濃度,因此復合膜光催化活性比單一TiO2薄膜高。
Gao Zhiyong , Wu Bosen , Lu Xili , Tang Zhenyu
2007, 36(9):1534-1538.
Abstract:采用動態(tài)機械分析儀(DMA)、透射電鏡(TEM)和示差掃描量熱分析儀(DSC)等手段,系統(tǒng)地研究了時效處理對TiNi合金阻尼行為的影響規(guī)律及其微觀機制。結果表明,第二相粒子對合金阻尼行為具有不同的影響。細小、彌散的Ti3Ni4相提高了TiNi合金相變過程中馬氏體的阻尼值,粗片狀的Ti3Ni4相對阻尼行為的影響較小。
Li Jianzhang , Zhang Litong , Cheng Laifei , Xu Yongdong , Li Douxing
2007, 36(9):1539-1544.
Abstract:在連續(xù)纖維增強陶瓷基復合材料中,界面調節(jié)脆性基體與脆性纖維之間匹配關系的功能以及自身特有的物理化學性質,決定著復合材料的整體綜合效能。本研究從實踐中發(fā)現(xiàn)界面區(qū)的存在,并嘗試提出界面區(qū)的概念。界面區(qū)是具有一定厚度,含有兩處界面(界面相/基體和界面相/纖維)和體相(界面相)的區(qū)域。采用透射電子顯微技術從微結構的角度研究了3DC/SiC內界面區(qū)與裂紋的相互作用行為。TEM觀察表明,由于裂紋偏斜/貫穿競爭隨時空的推演,基體主裂紋會在界面區(qū)的多處位置產生單多重偏斜、裂紋尖端前方應力集中誘發(fā)脫粘和開裂、納米尺度微裂紋橋連等相互作用,其發(fā)生的具體部位和方式由界面區(qū)內各種相關界面(或斷裂)韌性共同決定。此外,結合影響因素的討論,初步建立起3DC/SiC內基體裂紋與界面區(qū)相互作用的物理模型。
Liu Changjiu , Wang Huijing , Wu Huabin , Sun Dan
2007, 36(9):1545-1548.
Abstract:采用快速冷凍沉淀法制備出了非晶態(tài)納米氫氧化鎳。對制得材料樣品進行了XRD,SEM,TEM,DSC和比表面積與孔徑分析,將其制成MH-Ni電池正極材料進行充放電性能測試。結果表明:材料粉體為非品態(tài),顆粒粒度為納米級,類似球形。非晶納米Ni(OH)2的熱分解溫度286.4℃低于常規(guī)球形Ni(OH)2的熱分解溫度333.8℃,同時具有較大得比表面積和孔徑,分別為76.2089m^2·g^-1和37.7nm。與普通β-Ni(OH)2相比較,非晶態(tài)納米氫氧化鎳電極充電電壓低,放電電壓平臺時間長,且高達1.258V,放電比容量為349.85mAh/g,具有較好的循環(huán)性能,20次循環(huán)后其容量衰減僅為1.28%。
Wen Zhixun , Gou Wenxuan , Yue Zhufeng
2007, 36(9):1549-1553.
Abstract:采用緊湊拉伸(CT)試樣研究了3種不同溫度(950,850,760℃)和3種不同晶體取向([001],[011],[111])下鎳基單晶合金DD3的斷裂特征,采用光學顯微鏡和掃描電子顯微鏡觀察分析了裂紋擴展路徑及斷口形貌。采用率相關晶體滑移有限元程序對試件裂紋尖端三維分切應力場結構、裂紋啟裂和擴展機制以及滑移系激活規(guī)律進行了模擬計算分析。結果表明:晶體取向和環(huán)境溫度對裂紋啟裂和擴展以及斷裂強度和斷裂形式有較大的影響,低溫下裂紋擴展沿著特定的滑移帶方向,與裂紋平面成一斜角,[001]裂紋取向下為45°,[011]裂紋取向下為53.7°,[111]裂紋取向下為90°,這使得宏觀上裂紋擴展路徑呈現(xiàn)Z字形外觀。而溫度較高時,發(fā)生的Ⅰ型裂紋擴展與加載方向垂直。并且隨著溫度的升高,斷裂形式逐步由脆性斷裂轉化為韌性斷裂。
Zhang Wei , Li Ning , Wen Yuhua , Huang Shuke
2007, 36(9):1554-1557.
Abstract:研究了等通道轉角擠壓后時效處理對FeMnSiCrNiC合金碳化物的析出和形狀記憶效應的影響。結果發(fā)現(xiàn),擠壓態(tài)合金經973K時效處理150min后,平均晶粒尺寸約10btm,同時晶內和晶界處析出大量碳化物。碳化物析出在回復完成前即開始,擠壓產生的大量缺陷降低了碳化物析出的激活能,促進了碳化物析出。細晶強化和碳化物析出強化的共同作用顯著提高了合金的基體強度,抑制預變形中的塑性變形,使更多的變形由應力誘發(fā)馬氏體承擔。因此,合金形狀回復率達到89.4%(預變形4.33%時),比固溶態(tài)高120%,比直接時效高40%。
2007, 36(9):1558-1561.
Abstract:使用“固體與分子經驗電子理論”(EET)分別計算了純Mo,W原子的價電子結構表電子結構,使用“鍵距差法”(BLD)分別對純Mo,W及Mo.30W合金進行了計算,按照“固體與分子經驗電子理論”基本思想提出了雜階數(shù)目多則材料抗腐蝕性高的觀點。結果表明:Mo-30W合金的耐液態(tài)鋅的腐蝕性、彈性、塑性、強度等指標遠高于純Mo,W材料,更具有工業(yè)價值。
Long Zhaohui , Liao Shuzhi , Wu Xiaozan , Gui Xuchun , Deng Zhihong , Zhang Bangwei
2007, 36(9):1562-1565.
Abstract:用改進分析型嵌入原子模型(MAEAM)計算了Mo-Pd二元合金在2個典型溫度的邊際固溶度。在淬火溫度為1473K時,Pd在Mo(a相區(qū))中的邊際固溶度為0.6%(原子分數(shù),下同):Mo在Pd(聲相區(qū))中的邊際固溶度為26.8%;在包晶溫度2028K附近,Pd在Mo(a相區(qū))中的邊際固溶度為1.1%;Mo在Pd(聲相區(qū))中的邊際固溶度為29.5%。計算結果與已有理論和實驗結果大體上是吻合的。
Zhang Qi , Li Tingjü , Wang Tongmin , Jin Junze
2007, 36(9):1566-1569.
Abstract:Static simulation experiment is done for the Sn-3.5%Pb alloy of low-melting point to verify the effect of inner traveling magnetic field on the solidification microstructure of hollow tubular billet by continuous casting. The results show that the traveling magnetic field can provoke the circulation flow in the vertical section of molten metal, reduce the temperature gradient of solidification front and the cooling rate of molten metal, facilitate the transition from columnar to equiaxed structure, and refine the grains. So, the solidification microstructure of hollow tubular billet by continuous casting.was improved by the inner traveling magnetic field.
2007, 36(9):1574-1577.
Abstract:采用檸檬酸溶膠.凝膠法成功地合成了Sm^3+,Li^+摻雜的SrZn02系列熒光粉。用XRD,PL等手段研究了樣品的物相結構和光致發(fā)光性能。SrZnO2:Sm^3+樣品的激發(fā)主峰位于413nm附近,能有效地被近紫外光激發(fā);最大發(fā)射峰在607nm。在SrZnO2:Sm^3+熒光體中共摻雜Li^+后,樣品的晶化程度增加,晶格稍膨脹;在發(fā)光性能上,降低了基質的激發(fā)效率,也削弱了Sm^3+-O^2-的電荷轉移激發(fā)強度,但是增強了樣品的橙紅光發(fā)射。研究顯示,SrZnO2:Sm^3+,Li^+熒光體可望成為一種與InGaN管芯匹配的LED用紅色熒光粉。
Zhang Jianjun , Wang Yongxin , Chen Zheng , Liu Bing
2007, 36(9):1578-1583.
Abstract:基于Thomas—Fermi模型,系統(tǒng)定量地計算研究了在電場作用下Al6CuMg4準晶相對于Al-Cu-Mg固溶體及普通化合物的自由能和吉氏自由能的變化趨勢。結果表明:Al6CuMg。準晶相、Al2CuMg及Al-Cu-Mg固溶體的自由能與吉氏自由能,均隨著電場強度的增大而升高。正電場作用要高于負電場作用,但差距不大。Al6CuMg。準晶相的自由能與吉氏自由能相對于固溶體對電場的變化更為敏感,隨著電場的升高,Al6CuMg4與固溶體間的自由能與吉氏自由能的差值迅速增加。電場作用使得準晶相的不穩(wěn)定性增加,Al2CuMg的穩(wěn)定性顯著高于Al6CuMg4的電場穩(wěn)定性。對于Al-Cu-Mg固溶體,隨著Mg含量的增加,合金對電場的敏感性增強,但增大幅度要遠遠小于化合物與準晶相的增大幅度。
Ma Yilong , Liu Ying , Zhang Ran , Li Jun , Gao Shengji , Tu Mingjing
2007, 36(9):1584-1587.
Abstract:采用熔體快淬結合靜態(tài)晶化法,制備出高性能、低溫度系數(shù)雙相納米晶復合永磁材料(NdDy)11.5Fe81.4Nb1B6.1及(NdDy)11.5Fe76.4Nb1Co5B6.1,并著重研究了Co的添加對復合添加Dy,Nb磁體的磁性能、微觀結構以及高溫穩(wěn)定性的影響。結果表明:隨著Co含量的增加,內稟矯頑力先減小后增大,剩磁則先增加后減小,合金晶粒逐步細化;Co的添加并沒有降低磁體的磁通不可逆損失,當Co含量大于5%(原子分數(shù),下同)時,磁通不可逆損失大幅度提高。
2007, 36(9):1588-1591.
Abstract:對LF2鋁合金攪拌摩擦焊接接頭的靜載力學行為和疲勞特性進行了研究,建立了焊接接頭的孓Ⅳ曲線。力學實驗結果表明:LF2鋁合金攪拌摩擦焊接接頭的最高抗拉強度為252.8MPa,是母材抗拉強度的95.4%。疲勞實驗結果表明:攪拌摩擦焊接接頭表現(xiàn)出良好的疲勞性能,疲勞壽命N=10^5次的疲勞強度為59~65MPa。顯微組織分析表明:攪拌摩擦焊接接頭具有細小的等軸晶粒和狹窄的熱影響區(qū),阻礙了滑移帶的形成和裂紋的擴展,從而提高了接頭的疲勞性能。疲勞斷口分析顯示:隨著駐留滑移帶的擴展逐漸萌生裂紋,在交變應力作用下最終導致失效。
Li Rong , Zhou Shangqi , Liang Guoming , Sun Yuyang , Liu Shouping , Luo Xiaoling , Wan Yan
2007, 36(9):1592-1596.
Abstract:利用電荷自洽離散變分Xa(SCC—DV-Xa)方法計算了吸熱型金屬合金化對釩基貯氫材料性能的影響。結果表明:在V54H64中加入吸熱型金屬Cr,Mn,F(xiàn)e,Co,Ni后,隨著原子序數(shù)的增加,V51M2H64中H的凈電荷逐漸增加,V的凈電荷逐漸減?。粴浠颲51M2H64中V-H之間的離子性相互作用逐漸減弱,共價性相互作用逐漸增強。材料放氫的平衡壓力與其費米能有很好的一致關系,加入吸熱型金屬后,氫化物V51M12H64中費米能增加,氫化物更不穩(wěn)定,從而改善材料的吸放氫性能。
Wang Xuemin , Zeng Xiaoqin , Wu Guosong , Yao Shoushan
2007, 36(9):1597-1600.
Abstract:研究了AZ31鎂合金在釔離子劑量為5×10^16,1×10^17及5×10^17ions/cm^2注入條件下的氧化性能。純氧氣氛、500℃下的氧化實驗結果表明,釔離子注入能提高AZ31鎂合金的抗氧化性能,而且隨著注入劑量的增大,合金表面抗氧化性能提高越大。俄歇電子能譜(AES)和X光電子能譜(XPS)分析表明:釔離子注入以后,在鎂合金表面形成了具有雙層結構的氧化層,外層主要由MgO組成,而內層主要由Y2O3,MgO構成。這一新形成的氧化層有利于提高AZ31鎂合金的抗氧化性能。
Zhang Jinling , Wang Shebin , Wei Yinghui , Zhang Junyuan , Li Mingzhao , Xu Bingshe
2007, 36(9):1601-1604.
Abstract:在真空Ar氣氛中熔煉AZ91鎂合金,測定了不同精煉溫度下Mg元素的蒸發(fā)速率。結果表明,隨著精煉溫度的升高,Mg元素的蒸發(fā)量增大。通過計算可知,Mg的蒸氣壓是Al的10^9倍,是Zn的46倍,因此主要是Mg的蒸發(fā)而導致合金其他元素含量升高。XRD分析表明,蒸發(fā)物是Mg元素。結合Mg元素的蒸發(fā)機制,在該試驗條件下推導出Mg元素蒸發(fā)率的計算公式以及Mg元素的表觀傳質系數(shù)、蒸發(fā)率與精煉溫度的關系,計算得出Mg元素蒸發(fā)率為0.86×10^-3-1.35×10^3g/cm^2·s,Mg元素的表觀傳質系數(shù)在2×10^-5-24×10^-5cm/s范圍內。
Hou Xueling , Kong Junfeng , Li Shitao , Zhou Bangxin , Ni Jiansen , Xu Hui , Zhang Shaojie
2007, 36(9):1605-1607.
Abstract:為了解決Gd5Si2Ge2磁制冷合金居里點低,制冷溫區(qū)狹窄問題,采用合金化的方法,利用添加元素Sn代替Si或Ge,提高了Gd5Si1.9Ge2Sn0.1材料的居里溫度,同時保持工質材料Gd5Si2Ge2的巨磁熱效應,并相對于Gd5Si2Ge2合金的制冷溫區(qū)有了很大的拓展。
Ouyang Hongwu , Yu Wentao , Chen Xin , He Shiwen , Huang Jinsong
2007, 36(9):1608-1612.
Abstract:利用“球化效應”,在SLS設備上探索將異形Ti粉轉化為高性能球形粉末的可行途徑。通過系統(tǒng)地改變激光功率、掃描速度,以及選取合適的激光掃描間距,探明了形成“球化效應”的工藝條件,并在激光功率為600W,掃描速度為30mm/s時,獲得了較為理想的球形Ti粉。通過對球化過程進行理論分析,得出了選取激光掃描制備球形Ti粉工藝參數(shù)的準則。
Xin Shewei , Zhao Yongqing , Zheng Weidong , Wu Huan , Yang Haiying , Li Qian
2007, 36(9):1613-1616.
Abstract:Two Ti-V-Cr system burn-resistant titanium alloys of Ti-25V-15Cr-0.2Si and Ti-25V-15Cr-2Al-0.2Si were prepared. Their creep, thermal stability properties and microstructure were tested under different conditions. The result shows that Al strengthened the roomtemperature mechanical properties and reduced the creep and thermal stability properties of Ti-V-Cr system burn-resistance alloys. The microstructures of two alloys only contained a phase and Ti5Si3 phase under the experiment condition, other transition phases and intermetallic compounds were not found. During creep and thermal exposure processes, the decrease of structure stability and much more precipitated phases are attributed to the effect of alloying element Al which caused the reduction of thermal stability and creep properties of Ti-V-Cr burn resistant titanium alloy.
Yuan Xinjian , Sheng Guangmin , Qin Bin , Huang Wenzhan
2007, 36(9):1617-1622.
Abstract:采用純鎳箔作中間過渡層,在脈沖加壓擴散連接工藝下,對TA17鈦合金與0Cr18Ni9Ti不銹鋼進行了連接試驗,并測定了接頭的拉伸強度。結果表明:采用鎳箔作中間過渡金屬的脈沖加壓擴散連接,實現(xiàn)了鈦合金與不銹鋼的高效良好連接,接頭抗拉強度達到了334MPa。采用金相顯微鏡和掃描電鏡,對拉伸斷口形貌進行了觀察和分析;利用能譜儀(EDS)測定了拉伸斷口各區(qū)域內的微區(qū)成分;并對拉伸斷口進行了剝層試驗。結果表明:拉伸斷裂發(fā)生在Ni-Fe和Ni—Ti之間,Ni-Fe和Ni—Ti區(qū)均承載拉伸力,中間層Ni的存在成功地阻止了Fe與Ti之間的互擴散。
2007, 36(9):1623-1627.
Abstract:Ti5Si3-TiCo-Ti2Co multiphase intermetallic alloy with wear resistant has been fabricated by laser melt deposition process. The microstructure of intermetallic alloys is characterized by OM, SEM, XRD and EDS and the wear properties are evaluated in the room-temperature dry sliding wear conditions and the wear mechanism is discussed. It is found that the Ti5Si3-TiCo-Ti2Co multiphase intermetallic alloy has an excellent wear resistance under room-temperature dry sliding wear conditions. The wear mass loss increases very slowly, and the wear mass loss rate increases first then decreases with wear time increasing due to the high hardness of Ti5Si3, and the abnormal yield strength of intermetallics with temperature and the formation of smearing-layer on the worn surface.
Huang Lanping , Chen Kanghua , Li Song , Song Min
2007, 36(9):1628-1633.
Abstract:研究了高溫預析出對Al-Zn—Mg—Cu系7055合金的應力腐蝕、晶間腐蝕和剝蝕行為以及時效硬化的影響,并通過對預析出/時效組織的透射電鏡觀察,闡述了預析出對7055合金各種腐蝕行為和時效硬化的影響。組織觀察及腐蝕性能和力學性能測試結果表明:高溫預析出處理可使7055合金抗應力腐蝕性能得到明顯改善,合金應力腐蝕開裂界限應力強度因子局KISCC由7.4MPa·m^1/2提高至9.8MPa·m^1/2,合金抗拉強度仍能保持在680MPa左右。經高溫預析出處理后的7055合金晶間腐蝕、剝蝕敏感性降低,7055合金的剝蝕等級由EC降為EA-。同時,高溫預析出處理使晶界析出相粗化顯著、離散度增大,晶界平衡析出相的Cu含量為60.18at%,且晶界析出相Cu含量提高。
Li Hai , Wang Zhixiu , Zheng Ziqiao
2007, 36(9):1634-1638.
Abstract:采用常規(guī)拉伸和慢應變速率拉伸方法測試了Al-9.88Zn-2.40Mg-2.32Cu-0.12Zr鋁合金在T6,RRA及T73時效狀態(tài)下的力學性能和抗應力腐蝕性能,并通過SEM和TEM觀察了慢應變速率拉伸斷口形貌及析出相特征。TEM結果表明,T6,RRA和T73時效狀態(tài)的晶內析出相分別以GP區(qū)+η'相、η'相+η相、η相為主,并且晶內和晶界析出相尺寸以及晶界PFZ寬度依次增大:同時晶界析出相逐漸由長條狀連續(xù)分布逐漸轉變成球狀不連續(xù)分布。這些微觀組織特點使得3種時效狀態(tài)下實驗合金具有不同應力腐蝕開裂傾向、常規(guī)拉伸性能和斷口形貌特征。
Yin Zhoulan , Zhong Shengkui , Wang Zhixing , Chen Qiyuan
2007, 36(9):1639-1643.
Abstract:通過碳熱還原法合成了鋰離子電池正極材料Li3V2(PO4)3,考察了不同合成溫度、時間對產物晶形結構、形貌和電化學性能的影響。結果表明,當合成溫度、時間分別為800℃,20h時,所合成的樣品屬于單斜晶系,且粒度大小分布比較均勻,該材料以0.2C充放電,其首次放電容量為120mAh·g^-1,循環(huán)30次后其比容量達108mAh·g^-1。
He Yushi , Liao Xiaozhen , Ma Zifeng , Yuan Xianxia , Wang Baofeng , Jiang Yi
2007, 36(9):1644-1648.
Abstract:采用高溫固相碳熱還原法(CTR,Carbothermal Reduction)合成了LiFePO4/C復合正極材料。采用XRD,SEM以及BET等方法對產物進行表征。結果表明,所得LiFeP04/C材料有著單一的橄欖石型晶體結構。750℃下制備產物的BET比表面積為39.7002m^2/g。利用恒流充放電,循環(huán)伏安法(CV),電化學阻抗譜(EIS)等電化學手段研究了LiFePO4/C材料的電化學性質。結果表明:750℃下制備的LiFePO4/C復合材料在25℃工作溫度下,有著優(yōu)異的循環(huán)穩(wěn)定性和大倍率充放電性能,使用850ma/g(5C)的電流密度對電池充放電90次后,電池放電比容量仍能保持11lmAh/g。在55℃工作溫度下1C充放電倍率時,首次和第90次循環(huán)的放電比容量分別為14513mAh/g和142.9mAh/g。
Hou Guangya , Jin Zhihao , Zheng Xiaohui , Qian Junmin
2007, 36(9):1649-1652.
Abstract:使用Ca(NO3)2-P2O5乙醇溶液體系制備納米羥基磷灰石,研究了在該體系中水浴溫度、煅燒溫度、陳化時間等因素對粉體的相成分,粒度和結晶度的影響。結果表明:水浴溫度低,合成的粉體粒度小(約20nm),顆粒均勻且具有良好的分散性,但是結晶度較低;陳化后導致粉體粒度變大,結晶度增加;隨著煅燒溫度的升高,粉體的結晶度增加,600℃時可以得到結晶高的單一的羥基磷灰石粉體。在800℃煅燒時,羥基磷灰石發(fā)生部分分解。
Zhai Yongqing , Liu Yuanhong , Li Change , Zhang Yue
2007, 36(9):1657-1660.
Abstract:采用微波法快速合成了Y2O2S:Tb綠色熒光粉。用X射線衍射(XRD)儀、掃描電鏡(SEM)、熒光分光光度計等對合成產物的相結構、形貌、以及發(fā)光特性進行了研究。結果表明:材料的晶體結構為六方晶系,與Y2O2S相同。顆粒的形貌為類球形,分散性很好,平均晶粒尺寸在300nm左右。發(fā)射光譜由384,418,439,460,475,498,547,590,624nm等一系列窄帶發(fā)射峰組成,歸屬于Tb^3+從^5D3,^5D4到^7FJ(J=0~6)的躍遷。研究發(fā)現(xiàn)Tb的摻雜濃度對樣品的發(fā)射光譜有著很重要的影響,當其濃度為0.5%(摩爾分數(shù),下同)時,^5D3→^7FJ的藍光發(fā)射發(fā)生猝滅,當其濃度為9%時,^5D4→^7FJ的綠光發(fā)射發(fā)生猝滅。
Cheng Jikuan , Gao Jiqiang , Liu Junlin , Jiang Xian , Yang Jianfeng , Qiao Guanjun
2007, 36(9):1661-1664.
Abstract:研究了用物理氣相傳輸(PVT)法制備SiC單晶的過程中附加碳源對晶體生長速度及缺陷的影響,并將活性炭與SiC粉末一起加入到石墨坩堝中進行晶體生長。用XRD分別測定了晶體生長前后坩堝與活性炭的石墨化度,并用光學顯微鏡觀察了晶體中的缺陷。結果表明,隨晶體生長過程的進行石墨坩堝的活性降低,直接導致晶體生長速度減慢,并使籽晶表面Si液相形成的可能性增大,與Si液相相關的缺陷增多。活性炭的加入給生長過程提供了充足的碳源,提高了晶體的生長速度,并抑制了籽晶表面Si液相的形成,從而降低了與Si液相相關缺陷出現(xiàn)的幾率。
2007, 36(9):1665-1667.
Abstract:采用攪拌球磨法制備了納米復相Nd2Fe14B/a—Fe永磁合金。借助X射線衍射(XRD)、差示掃描量熱法(DSC)、透射電子顯微鏡(TEM)等分析方法研究了不同球磨時間及晶化處理溫度對合金微觀組織和磁性能的影響規(guī)律。結果表明:隨球磨時間的延長,Nd2Fel4B相及a-Fe相的晶粒尺寸迅速減小,球磨5h后粉末由非晶相和晶粒尺寸約為10nm的a-Fe相組成,當晶化處理溫度為650℃,保溫時間為30min時,兩相的晶粒尺寸比較細小,此時磁性能最好,達到Br=1.06T,Hci=347kA/m,(BH)m=142kJ/m^3。
Wu Xueqing , Ma Mo , Tan Chaogui , Liu Xuebin , Lin Jianguo
2007, 36(9):1668-1671.
Abstract:采用單輥甩帶法制備出完全非晶態(tài)的Al88Ni6La6薄帶,并用X射線衍射(XRD)儀和示差掃描量熱計(Dsc)對該非晶薄帶的非晶特性及其晶化過程進行了研究。該非晶薄帶的晶化過程分為兩步,其晶化溫度約為239℃和332℃。在0.01mol/L NaCl溶液中對完全非晶態(tài)的A188Ni6La6試樣及其部分晶化和完全晶化試樣的電化學腐蝕行為進行了研究。結果表明,部分晶化的試樣表現(xiàn)出最佳抗電化學腐蝕性能,而經過完全晶化的試樣,其抗腐蝕性能明顯下降。
Li Qian , Wu Zhu , Lu Xionggang , Zhou Guozhi , Xu Kuangdi
2007, 36(9):1672-1676.
Abstract:The Mg-based hydrogen storage composites have been successfully prepared by mechanochemical synthesis using Ti0.32Cr0.35V0.07Fe0.26 and Ni as additives. The hydrogen sorption-desorption characteristics were mensurated by an isovolumetric method, and the structures and constitutes, and the surface and body properties were investigated by XRD, SEM, TEM, GC and XPS, respectively. The correlations of the milling time and alloy components with the structure and hydrogen sorption-desorption property were elucidated, then the hydrogen sorption-desorption mechanism was discussed. The results indicate that the hydrogen sorption-desorption temperature decreased and the kinetic properties are improved because the fine Ti0.32Cr0.35V0.07Fe0.26 and Ni particles covering magnesium matrix act as the catalytic phases to produce a significant amount of nanoparticles in favor of the decrease of temperatures and the increase of speed for hydrogen sorption-desorption.
Wei Zhiqiang , Xia Tiandong , Jiang Jinlong , Shen Jie , Xu Yangtao , Zhang Penglin , Yan Pengxun
2007, 36(9):1677-1680.
Abstract:采用陽極弧放電等離子體法成功制備了銀納米粉體,并利用X射線衍射(XRD)、透射電子顯微鏡(TEM)和選區(qū)電子衍射(SAED)對樣品的形貌、晶體結構、粒度及其分布進行性能表征。利用靜態(tài)表面吸附儀測試樣品對N2的吸附-脫附等溫線,依據(jù)BJH理論模型分析樣品的孔結構;利用BET吸附公式計算出樣品的比表面積。結果表明:所制備的銀納米粉末的晶體結構與相應的塊體材料基本相同,為fcc結構,其粒度主要分布在10~50nm,平均粒度為26nm,比表面積為23.81m^2/g,呈規(guī)則的類球形分布。
Zhang Yuejü , Li Xiaojie , Yan Honghao , Liu Kaixin , Qu Yandong , Wang Xiaohong
2007, 36(9):1681-1684.
Abstract:改進爆炸實驗裝置,并利用該裝置實施了預熱爆炸壓實實驗。以商業(yè)ITO納米陶瓷粉末為原料,通過壓力機將粉末壓實到大約50%理論密度的初始壓坯,選擇預熱溫度為800℃以上進行爆炸壓實,從而獲得了致密且晶粒在納米量級的良好燒結體。結果表明:預熱爆炸燒結體微觀組織結構均勻,晶粒尺寸分布在200nm左右,且將燒結體在掃描電鏡上放大到100,000倍時仍未發(fā)現(xiàn)明顯孔洞和微裂紋等缺陷。認為宏觀塑性變形和晶粒長大是導致良好燒結的2個主要機制。
2007, 36(9):1685-1688.
Abstract:從Pd—C催化劑廢料回收Pd(N03)2,然后在SDS/Brij30/H20體系O/W微乳液中制備納米鈀。結果表明:制備的鈀納米粒子的粒度在5-200nm之間:使用該體系不需外加還原劑,可直接利用非離子表面活性劑Brij30作為還原劑,簡化后續(xù)單元操作。并初步探討了SDS/Brij30/H2O體系O/W微乳液中納米鈀的制備機制。
Li Mingzhao , Zhang Junyuan , Wang Xiaomin , Wang Shebin , Xu Bingshe
2007, 36(9):1689-1692.
Abstract:In the process of vacuum melting AZ31 magnesium alloy, Nb powder and Mg-Nd intermediate alloy were added, respectively. The composition of inclusion and absorptivity of Nd in magnesium alloy were measured. The microstructure was observed, the precipitating phases were identified, and the approaches of increasing the mechanical properties of magnesium alloy were dicussed. The results show that amount of inclusion was decreased under vacuum condition. The absorptivity of Nd upon adding Mg-Nd intermediate alloy was higher than that upon adding Nd powder, simultaneously, new phases NdAl2 and Mg12Nd were formed, which fined grains and improved the mechanical properties of the alloy.
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