Effects of Y2O3 on the property of copper based contact materials
掺铜TiO_2光催化剂光催化氧化还原性能的研究
第23卷 第5期感光科学与光化学Vo l.23 N o.5 2005年9月Pho tog raphic Science and P hotochemistr y Sept.,2005 研究论文掺铜TiO2光催化剂光催化氧化还原性能的研究吴树新1,2,3,尹燕华2,何 菲1,秦永宁1(1.天津大学化工学院,天津300072;2.第718研究所,河北邯郸056027;3.唐山师范学院化学系,河北唐山063000)摘 要:利用浸渍法制备了掺铜二氧化钛光催化剂,分别以乙酸降解和二氧化碳还原反应为探针,研究了催化剂的光催化氧化光催化还原性能.结果表明,铜掺杂能显著提高催化剂的光催化性能;结合光电子能谱、X光衍射分析等物理表征结果,对铜掺杂改性机制进行了讨论.关键词:光催化;乙酸;铜离子掺杂;XPS;TiO2;二氧化碳还原文章编号:1000 3231(2005)05 0333 07 中图分类号:O64 文献标识码:A纳米级二氧化钛具有合适的禁带宽度、较大的比表面积、较高的光化学稳定性、较强的氧化还原性及无毒、成本低等优点,被广泛用作光催化反应的催化剂,但从其光催化效率看,还存在半导体载流子复合率高等缺点[1].为提高光催化效率,必须有效抑制光生载流子的复合,为此,人们采用了多种手段如贵金属沉积、利用不同能级的半导体进行耦合以及金属离子掺杂等对纳米二氧化钛进行改性[2 4].其中过渡金属离子掺杂被认为是一种有效手段,但人们对掺杂改性的机理还未达成共识,而且掺杂催化剂的评价大多仅考察其光催化氧化性能[5,6]或光催化还原性能[7],而从氧化和还原两个方面同时考察掺杂催化剂的研究还少见报道.本文利用浸渍法制备了掺铜二氧化钛光催化剂,分别以乙酸降解和二氧化碳还原反应为探针,考察了催化剂的光催化氧化和光催化还原性能,并利用光电子能谱、X光衍射分析等物理表征手段,对铜掺杂改性机制进行了初步的探讨.1 实验部分1.1 催化剂的制备与表征收稿日期:2005 03 07;修回日期:2005 06 03.通讯联系人:尹燕华.作者简介:吴树新(1968 ),男,副教授,博士研究生,主要从事绿色化学和新型催化技术的研究,E mail:hdwushx @.333掺铜二氧化钛利用浸渍法得到:用计量的锐钛矿型二氧化钛超声分散于计量的硝酸铜溶液中,超声时间为15min.然后在烘箱中80 烘干,450 焙烧2h.得到掺铜量分别为0.08%、0.2%、0.8%、2%、8%、10%的掺铜二氧化钛.采用日本理学D/MAX 2038型X 射线衍射仪分析催化剂物相结构;实验所用的XPS 装置是美国Pekin Elmer 公司生产的PH 1600型能谱仪,以本体的污染碳Cls 结合能(284.6eV)为标准,对样品进行核电校正,从而确定元素的结合能.1.2 光催化剂的活性评价反应器为三层同心圆筒形装置[8],最外两层为普通玻璃,中间层由石英玻璃制成.光源为125W 中压汞灯,主波长为365nm.以乙酸水溶液降解评价其光催化氧化性能:将0.6g 催化剂加入300mL 浓度为250mg/L 的乙酸水溶液中,摇匀.打开汞灯预热5min,通冷却水,使反应体系温度维持在室温.光照过程中,中速电磁搅拌,以200mL/m in 通入空气.反应2.5h 后,分析体系COD,扣除物理吸附和光解的影响,计算降解率[9].以二氧化碳还原反应评价催化剂光催化还原性能:反应底液为碳酸钠和亚硫酸钠的混合溶液,体积为200mL,其中碳酸钠的浓度为0.25mol/L,亚硫酸钠的浓度为0.08mol/L,催化剂投加量为0.2g /100mL,二氧化碳流量为120mL/min,以反应6h 后还原产物的种类及累积浓度作为评价催化剂性能的指标,还原产物分析方法见文献 .2 结果与讨论表1是掺铜前后催化剂光催化氧化性能的比较.可以看出,随着掺铜量从质量分数0.08%提高到10%,乙酸的消除率先是逐渐提高,并在0.2%时达到最大,随后便逐渐降低.表1 掺杂前后光催化氧化性能的比较Comparison of photocatalytic oxidation activity before and after doping掺杂浓度(%,质量分数)00.080.20.8210100降解率D (%)21.5255.263.1635.8222.629.3 4.7图1是未掺杂二氧化钛和掺杂0.2%铜的二氧化钛催化剂上光催化还原二氧化碳还原产物的情况.从图中可以看出,未掺铜催化剂上光催化还原产物只有甲酸和甲醛,而掺铜后的催化剂上除了这两种产物外,还出现了甲醇,说明掺铜后催化剂的光催化还原能力得到了提高.图2是掺铜前后样品的XRD 图,发现掺铜催化剂除了二氧化钛外,并未出现其它晶相.考虑到掺铜量为0.2%,铜物种可能进入二氧化钛晶格中,或者高度分散于二氧化钛表面[10].利用XPS 分析了掺铜催化剂表面组成和元素价态,发现铜含量为0.8%,高于掺杂 杨秋华.纳米钙钛矿光催化性能的研究[D].博士学位论文,天津大学化工学院,2002.334 感 光 科 学 与 光 化 学第23卷图1 掺杂前后催化剂上还原产物情况The reduction products on th e doped(0.2%)and undoped catal ysts量0.2%,说明铜物种有表面富集的倾向.图3是掺铜0.2%的催化剂的XPS 图谱.根据峰形特点及元素结合能数据可知,催化剂表面的铜物种有两类,932eV 附近的+1价铜及933eV 附近的+2价铜[11].氧物种也是两类结合能,即位于529eV 的晶格氧和530eV 附近的吸附氧[12].图2 掺杂前后的XRD 图D patterns of catalysts (a)before and (b)after doping(0.2%)表2给出了掺铜催化剂的O1s XPS 拟合结果.从图3(a)和表2可知,掺杂前后催化剂表面虽然都存在两类氧种,但铜掺杂使表面吸附氧提高了.在光催化氧化过程中,表面吸附氧对于捕获光生电子、抑制电子空穴复合具有非常重要的作用[13].这很可能是掺铜催化剂光催化氧化性能得以改善的原因之一.对于光催化还原过程,由于反应在二氧化碳气氛中进行,因此,催化剂的表面吸附氧捕获电子的过程将被抑制,表面吸附氧性能对光催化反应的影响则可以忽略.所以,掺铜催化剂光催化还原性能的改善不能从吸附氧的角度加以解释,一定存在着其它原因,尚待进一步研究.第5期吴树新等:掺铜T iO 2光催化剂光催化氧化还原性能的研究335图3 掺铜TiO 2的XPS 图谱The analysis and fitting of the XPS spectra of T i O 2doped w ith copper(a)O1s,(b)Cu2p 3/2,(c)T i2p 3/2表2 O 1s 的XPS 拟合结果Fitting res ults of O1s XPS电子结合能(E BE /eV)氧物种类别氧物种浓度(%,体积分数)掺杂前529.60晶格氧81.97530.65吸附氧10.03掺杂后529.45晶格氧62.5530.59吸附氧37.5表3给出了不同掺铜量催化剂的O1s 和Cu2p 3/2的XPS 结果.从表3可知,随着掺铜量的提高,吸附氧单调增加.而Cu +含量则在0.2%达到最大后开始下降,直至10%掺铜时,+1价铜消失,只剩下+2价铜.表3 O1s 和Cu2p 3/2的XPS 拟合结果Fitting results of O1s and Cu2p 3/2XPS of the catalysts掺杂浓度(%,质量分数)00.080.2210吸附氧含量(%,体积分数)10.0333.4537.539.7944.01Cu +含量(%,质量分数)027.5236.3125.520图4表示的是Cu +/Cu 2+和甲醇产生量随催化剂掺铜量的变化情况.从图4中可知,二者的变化具有大体一致的趋势,这说明掺铜催化剂的光催化还原性能的提高可能与 336 感 光 科 学 与 光 化 学第23卷Cu +/Cu 2+值的大小有关.图4 产物甲醇、Cu +/Cu 2+随掺杂量的变化Variation of Cu +/Cu 2+and amount of methanol w ith dopant level在所研究的各掺铜量情况下,掺铜量为0.2%的催化剂光催化氧化活性也最高,因此Cu +/Cu 2+值的大小可能也与光催化氧化性能有关.作者认为低价铜的出现可能使光催化氧化反应体系中进行着如下的电子转移过程:Cu ++O adsO ads -+Cu 2+ (界面电子传递)Cu 2++e -cb Cu + (光生电子捕获)一方面,促进了光生电子的捕获,有效抑制了与空穴的复合.另一方面,增加了表面吸附氧捕获电子的机会,因而能生成更多具有强氧化性的过氧化氢自由基和羟基自由基,使得催化剂光催化氧化性能得以提高.而在光催化还原反应体系中,催化剂还原性能改善的可能过程是:Cu 2++e CBCu 1+ (光生电子的捕获)Cu 1++CCu 1++C* (捕获的电子传递给碳物种,C 表示碳物种)C*HCOOH e H CHO e CH 3OH通过捕获电子抑制了电子和空穴的复合,提高了光催化效率,通过向碳物种传递电子,促进了还原反应的进行.掺铜量为10%时,表面吸附氧量最大,但光催化氧化活性并未达到最大,这可能与Cu +的量小影响了电子转移过程导致电子空穴复合加快有关.总之,低价铜的出现对于形成Cu +/Cu2+,进而对催化剂光催化氧化还原性能的改善起到了关键作用.在前面的XRD 研究中,作者发现掺杂催化剂样品并未出现铜物种的晶相.另外,前文研究结果[5]显示,当掺杂量大于8%时,二氧化钛表面也只有二价铜离子.这说明掺杂铜量很少并且高度分散在催化剂表面,是产生低价铜的条件.高度分散的二价铜离子具有更强的反应活性,TPR 的结果也显示了这种高度分散性和较强的氧化还原活性[14].郑小明等人[15]在研究二氧化铈负载的氧化铜时,发现负载一定含量的氧化铜第5期吴树新等:掺铜T iO 2光催化剂光催化氧化还原性能的研究337后,XPS 分析发现了低价铜,并认为这与Ce 4+/Ce 3+有关.结合他们的研究结果,作者认为,在本文研究的体系中,高度分散的二价铜离子可能通过以下途径部分生成低价铜:Cu 2++Ti 3+Cu 1++Ti 4+由于Ti 3+被氧化成Ti 4+,所以XPS 分析中未发现T i 3+,这和实验结果相吻合.当然,低价铜形成的原因有待进一步研究.3 结论铜掺杂(0.2%)使催化剂的光催化氧化和还原性能都能得到显著改善.Cu +、Cu 2+共存可能有助于抑制电子空穴复合,从而提高催化剂的光催化性能.参考文献:[1] Choi W Y,Termin A.The role of metal ion dopents in quantum sized T i O 2:correlation betw een photoreactivity andcharge carrier recombination dynamics[J ].J.Phys.Chem.,1994,98:13669 13679.[2] 崔玉民,范少华.复合纳米微粒Rh 3+/TiO 2/S nO 2的合成、表征及光催化降解4 (2 吡啶偶氮)间苯二酚的研究[J].感光科学与光化学,2003,21(3):161 168.Cui Y M ,Fan S H.Synthesis,characteri zati on and applicati on of complex nanometer particles of Rh 3+/T iO 2/SnO 2in photocatalytic degradati on of PAR[J].Photographic S cience a nd Photochemistry ,2003,21(3):161 168.[3] 卢 萍,姚明明,张 颖,等.过渡金属离子的掺杂对T iO 2光催化活性的影响[J].感光科学与光化学,2002,20(3):185 190.Lu P,Yao M M ,Zhang Y,et al .The effect of doping transition metal ion on photocatalysis of TiO 2and its property[J].Photog rap hic Scie nc e and Photoche mistry ,2002,20(3):185 190.[4] 汤 斌,张庆庆.光析出二氧化钛负载银膜的制备及其光催化特性[J].感光科与光化学,2003,21(5),328 333.T ang B,Zhang Q Q.The preparation of si lver loaded titanium dioxide film an d its photocatalytic property[J].Photo gr ap hic S cience and Photochemistry ,2003,21(5):328 333.[5] 吴树新,马 智,秦永宁,等.掺铜二氧化钛光催化剂的XPS 研究[J].物理化学学报,2003,19(10):967 969.W u S X ,M a Z,Qin Y N,et al .XPS study of copper dopi ng T iO 2photocatalyst[J].J.A cta Chimica S inica,2003,19(10):967 969.[6] 吴树新,马 智,秦永宁,等.过渡金属掺杂二氧化钛光催化性能的研究[J ].感光科学与光化学,2005,23(2):94 101.W u S X,M a Z,Qin Y N,et al .S tudy on photocatalytic acti vity of transition metal oxide 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L,Stephanopoulos M F.Reduction characteristics of copper oxide i n cerium and zirconium oxide systems[J ].App lied Catalysis ,A :G eneral ,1998,171:13 29.[12] 梁新义,秦永宁,马 智,等.超声共沉淀法制备纳米结构LaNiO 3及其性质[J].物理化学学报,2002,18(6):567 571.Liang X Y,Qin Y N,M a Z,et al .Properties and sonochemical preparation of nanostructured LaNiO 3[J ].Acta Phys. Chim.Sin.,2002,18(6):567 571.[13] Linsebigler A L,Luo G Q.Photocatalysi s on T i O 2surface :principles,mechanisms and selected results[J].Chem.Rev .,1995,95:735 738.[14] 吴树新,尹燕华,秦永宁,等.掺铜方法对二氧化钛光催化氧化还原性能的影响[J].河北大学学报(自然科学版),2005,印刷中.W u S X ,Yin Y H ,Qin Y N,et al .Photocatalytic activity of copper doping TiO 2prepared by several methods[J].Jou rnal of Hebei Univ ersity (Natural S cience Edition ),2005,in press.[15] 蒋晓原,周仁贤,郑小明,等.CuO/Ce 2O 催化剂的催化氧化性能及其表征[J].中国稀土学报,2002,20(2):111115.Jiang X Y,Zhou R X,Zheng X M ,et al .Characterization of catalyti c properties of CuO/CeO 2mixed oxides [J].Jou ral o f The Chinese Rare Earth S ociety ,2002,20(2):111 115.Photocatalytic Redox Performance of CopperDoped TiO 2PhotocatalystWU Shu x in 1,2,3,Y IN Yan hua 2,HE Fei 1,Q IN Yong ning 1(1.School of Chemical Engineerin g and Technology,Tia nj in Univer sity,Tian j in 300072,P.R.China ;2.The 718th Rese arch Institute,Handan 056027,Hebei,P.R.China;3.T an g shan T ea cher s College,Tangshan 063000,H e bei,P.R.China)Abstract:Copper doped tit anium dioxide was prepared by impregnat ion of T iO 2materials with aque ous solution of Cu(NO 3)2under ult rasonic irradiation,followed by calcinations at 450 .T he cata lysts were charact erized by X ray diffraction(XRD)and X ray photoelectron spectrosc opy(XPS).T he photocatalytic activity of the doped catalysts were evaluated using the react ion of photocatalytic oxidat ion of acetic and photocatalytic reduction of CO 2.T he results show that t he photocatalytic ac t ivit y can be significant ly improved by doping c opper.T he raised content of adsorbed oxygen and co ex ist ence of Cu 2+and Cu +are likely to be two of the reasons responsible for the improved photo cat alyt ic act ivity.Key words:photocatalyt ic;acet ic acid;copper ion doping;XPS;T iO 2;CO 2reduct ion Corresponding author:YIN Yan hua 第5期吴树新等:掺铜T iO 2光催化剂光催化氧化还原性能的研究339。
铜材料的高温氧化行为研究与优化
铜材料的高温氧化行为研究与优化铜是一种常见金属材料，在许多领域都有广泛应用，例如电子、建筑、航空航天等。
然而，在高温环境下，铜材料容易发生氧化反应，导致其性能下降甚至损坏。
因此，研究铜材料的高温氧化行为并寻找优化方法变得尤为重要。
一、铜材料的高温氧化行为高温氧化指的是铜材料在高温条件下与氧气发生反应的过程。
铜在高温环境中会与氧气发生氧化反应，生成氧化铜。
氧化铜的产生不仅会导致铜材料的颜色变化，还会影响其物理性质和化学性质。
1. 氧化层形成过程在高温环境中，铜材料表面会出现一层氧化层。
氧气与铜发生反应，首先生成氧化亚铜（Cu2O），然后继续与氧气反应生成二氧化铜（CuO）。
氧化铜形成的速度与温度有关，温度越高，氧化层形成越快。
2. 影响因素铜材料的高温氧化行为受到多种因素的影响，包括温度、氧气浓度、气氛成分等。
温度是影响氧化层形成速度的主要因素，温度升高会加速氧化反应的进行。
氧气浓度越高，氧化层形成越厚。
此外，不同的气氛成分对铜材料的氧化行为也有影响，例如存在硫化物的气氛会加速铜的氧化。
二、铜材料高温氧化行为研究方法为了深入了解铜材料的高温氧化行为并寻找优化方法，研究人员采用了多种方法进行实验研究。
1. 热重分析热重分析是一种常用的实验手段，用于测量材料在不同温度下的质量变化。
通过热重分析，可以得到铜材料在高温下的氧化速率、氧化动力学参数等信息。
2. 电化学方法电化学方法是研究铜材料高温氧化行为的重要手段之一。
通过浸泡铜试样于电解液中，在一定电位下进行实验，可以得到铜材料的氧化电位、氧化电流等数据，从而推断出铜材料的氧化行为。
3. 表面分析技术表面分析技术包括扫描电镜（SEM）、能谱仪（EDS）等，可以观察铜材料表面的形貌和元素分布情况。
通过分析铜材料表面的微观结构，可以揭示其氧化行为的细节。
三、铜材料高温氧化行为的优化方法基于对铜材料高温氧化行为的研究，研究人员提出了一些优化方法，以延缓铜材料的氧化速度，提高其高温稳定性。
Ni含量对Sn-0.7Cu无铅钎料钎焊性能的影响
Vol. 11, No. 9September 2021第11卷第9期2 0 2 1年9月有色金属工程Nonferrous Metals Engineeringdoi ：10. 3969/j. issn. 2095-1744. 2021. 09. 007Ni 含量对Sn-0. 7Cu 无铅钎料钎焊性能的影响樊江磊王宁格翟恒涛⑺，梁柳博1，2,刘建秀1,2(1.郑州轻工业大学机电工程学院河南省机械装备智能制造重点实验室，郑州450002；2.郑州轻工业大学河南省先进材料成型与测试工程技术研究中心，郑州450002)摘 要：以Sn-0. 7Cu 无铅钎料为基础，以改善二元Sn-Cu 钎料合金的性能为目标,研究了 Ni 含量对Sn-0. 7Cu 钎料合金组织和 性能的影响。
通过组织观察、力学性能测试、熔化特性测试、润湿性能测试、电阻率测试、耐腐蚀性测试、时效处理等，研究了 Ni 含 量对Sn-0. 7Cu-^Ni(^=0. 5.1. 0,1. 5.2. 0)钎料合金凝固行为和钎焊性能的影响规律。
结果表明：随着Ni 含量添加，金属间化合 物相(Ni 3Sn 4)体积分数逐渐增大,Ni 含量为2%时,硬度最大值为14.2 HV ；Ni 含量为0.5%时，熔程最小为4.4 °C ；Ni 含量为1% 时，铺展面积最大值为92. 4 当血含量为2%时，电阻率最大为1.1X 10_7 n • m ；IML 厚度随着时效时间的延长先增加后趋于均匀；当Ni 含量为2%时，钎料在酸性腐蚀条件下最稳定。
关键词:Sn-Cu-Ni 系无铅钎料;微观组织;力学性能;钎焊性能中图分类号:TG42 文献标志码：A 文章编号：2095-1744(2021)09-0046-10Effect of Ni Content on Solder Ability of Sn-0. 7Cu Lead-free SolderFAN Jianglei 1'2 ,WANG Ningge 1'2 ,ZHAI Hengtao 1'2, LIANG Liubo 1'2 ,LIU Jianxiu 1'2(1. Henan Key Laboratory of Intelligent Manufacturing of Mechanical Equipment , School of Mechanical and Electrical Engineering ,Zhengzhou University of Light Industry ,Zhengzhou 450002,China ；2. Henan Engineering Research Center of Advanced Materials Processing and Testing , Zhengzhou University ofLight Industry , Zhengzhou 450002, China)Abstract : In order to improve the properties of binary Sn-Cu solder alloy , the effect of Ni content onMicrostructure and properties of Sn-0. 7Cu solder alloy was studied. The effect of Ni content on solidification behavior and brazing properties of Sn-0. 7Cu-^：Ni (h = 0. 5, 1. 0, 1. 5, 2. 0) solder alloy was investigated by the microstructure characterization , mechanical property test, melting property test, wettability test, resistivity test, corrosion resistance test and aging treatment. The results show that the volume fraction of intermetallic phase(Ni 3Sn 4)increases gradually with the addition of Ni. When the Ni content is 2%, the maximum hardness is 14. 2 HV ； when the Ni content is 0.5%, the minimum melting range is 4. 4 °C ； when the Ni content is 1 %, the maximum spreading area is 92・ 4 mm 2 ； when the Ni content is 2% ,the maximum resistivity is 1. 1X10-7 Q ・ m. Theresults show that the thickness of IML increases firstly and then tends to be uniform with the prolongation of aging time ； when the Ni content is 2% ,the solder is the most stable under acid corrosion condition.Key words : Sn-Cu-Ni lead-free solder ； microstructure ； mechanical ； properties ； brazing properties收稿日期：2021-01-08基金项目：国家自然基金资助项目(U1904175)；郑州市重大科技创新专项(2O19CXZXOO65);2O18年度河南省高等学校青年骨干教师培养计 划项目(2O18GGJSO9O);河南省研究生教育改革与质量提升工程项目(YJS2021AL026)Fund : Supported by the National Natural Science Foundation of China(U1904175) ； Zhengzhou Major Science and Technology Innovation Project (2019CXZX0065) ； Training Plan for Young Backbone Teachers of Colleges and Universities in Henan Province in 2018 (2018GGJS090)；Postgraduate Education Reform and Quality Improvement Project in Henan Province(YJS2021AL026)作者简介:樊江磊(1983—),男，博士，副教授，主要从事金属材料成型与凝固技术研究。
La元素对MoSi_(2)涂层的宽温域氧化行为影响
第33卷第3期中国表面工程Vol．33No．32020年6月CHINA SUＲFACE ENGINEEＲINGJune 2020收稿日期：2019-08-03；修回日期：2020-08-27通信作者：张世宏（1981—），男（汉），教授，博士；研究方向：表面技术；E-mail ：zsh136********@163．com 基金项目：国家自然科学基金（51671002）；安徽省重点研究与开发计划项目（1804b06020370）Fund ：Supported by National Science Foundation of China （51671002）and Anhui Provincial Key Ｒesearch and Development Program（1804b06020370）引用格式：杨英，毛绍宝，巫业栋，等．La 元素对MoSi 2涂层的宽温域氧化行为影响［J ］．中国表面工程，2020，33（3）：152-159．YANG Y ，MAO S B ，WU Y D ，et al．Effects of La element on oxidation behavior of MoSi 2coatings in wide temperature range ［J ］．China Surface Engineering ，2020，33（3）：152-159．doi ：10.11933/j.issn．10079289.20190803001La 元素对MoSi 2涂层的宽温域氧化行为影响杨英1，2，毛绍宝2，3，巫业栋1，2，3，张世宏1，2，3（1．安徽工业大学先进金属材料绿色制备与表面技术教育部重点实验室，马鞍山243002；2．安徽工业大学现代表界面工程研究中心，马鞍山243002；3．安徽工业大学材料科学与工程学院，马鞍山243002）摘要：采用包渗法在稀土La 2O 3掺杂钼合金基体上制备MoSi 2涂层，并就La 元素对MoSi 2涂层宽温域氧化行为的影响机制进行了系统研究。
EBSD在超细硬质合金WC晶粒尺寸统计中的应用
EBSD在超细硬质合金WC晶粒尺寸统计中的应用李园园;徐银超;林江华;左锐;于涛;温光华;陈响明【摘要】As the WC grain size of cemented carbide decreasing,the WC grain size statistic becomes rather more difficult. Relying on a lots experiment, the authors succeeded in applying EBSD technology for WC grain size statistic of superfine WC-Co cemented carbide material. For sample A (with practical grain size of 0.2~0.4μm), the average grain size was determined as 0.36μm by EBSD. At the same time, several other grain size statistic methods were used to compare and analysis. Besides, sample B (with finer WC grains of 0.1~0.3μm) was processed in two different sintering temperatures; and the effect of temperature on superfine WC grain growth was also explored.%硬质合金中WC晶粒度的统计随其尺寸的降低，难度大幅升高。
本文作者在多次实验的基础上，成功地将电子背散射衍射(EBSD)技术应用于超细 WC-Co 硬质合金 WC 晶粒尺寸统计。
以样品 A 合金(晶粒度约0.2～0.4μm)为例，应用EBSD统计其平均晶粒尺寸为0.36μm的同时，还与其他晶粒度统计方法进行对比分析。
Effect of alloying elements on the microstructure and mechanical properties of nanostructured
LetterEffect of alloying elements on the microstructure and mechanical properties of nanostructured ferritic steels produced by spark plasmasinteringSomayeh Pasebani,Indrajit Charit ⇑Department of Chemical and Materials Engineering,University of Idaho,Moscow,ID 83844,USAa r t i c l e i n f o Article history:Received 23November 2013Received in revised form 23January 2014Accepted 29January 2014Available online 15February 2014Keywords:NanostructuresMechanical alloying Powder metallurgyTransmission electron microscopy High temperature alloya b s t r a c tSeveral Fe–14Cr based alloys with varying compositions were processed using a combined route of mechanical alloying and spark plasma sintering.Microstructural characteristics of the consolidated alloys were examined via transmission electron microscopy and atom probe tomography,and mechanical prop-erties evaluated using microhardness nthanum oxide (0.5wt.%)was added to Fe–14Cr leading to improvement in microstructural stability and mechanical properties mainly due to a high number den-sity of La–Cr–O-enriched nanoclusters.The combined addition of La,Ti (1wt.%)and Mo (0.3wt.%)to the Fe–14Cr base composition further enhanced the microstructural stability and mechanical properties.Nanoclusters enriched in Cr–Ti–La–O with a number density of 1.4Â1024m À3were found in this alloy with a bimodal grain size distribution.After adding Y 2O 3(0.3wt.%)along with Ti and Mo to the Fe–14Cr matrix,a high number density (1.5Â1024m À3)of Cr–Ti–Y–O-enriched NCs was also detected.For-mation mechanism of these nanoclusters can be explained through the concentrations and diffusion rates of the initial oxide species formed during the milling process and initial stages of sintering as well as the thermodynamic nucleation barrier and their enthalpy of formation.Ó2014Elsevier B.V.All rights reserved.1.IntroductionNanostructured ferritic steels (NFSs),a subcategory of oxide dis-persion strengthened (ODS)steels,have outstanding high temper-ature strength,creep strength [1,2]and excellent radiation damage resistance [3].These enhanced properties of NFSs have been attrib-uted to the high number density of Y–Ti–O-enriched nanoclusters (NCs)with diameter of 1–2nm [4].The Y–Ti–O-enriched NCs have been found to be stable under irradiation and effective in trapping helium [5].These NCs are formed due to the mechanical alloying (MA)of Fe–Cr–Ti powder with Y 2O 3during high energy ball milling followed by hot consolidation route such as hot isostatic pressing (HIP)or hot extrusion [6–8].Alinger et al.[4]have investigated the effect of alloying elements on the formation mechanism of NCs in NFSs processed by hot isostatic pressing (HIP)and reported both Ti and high milling energy were necessary for the formation of ler and Parish [9]suggested that the excellent creep properties in yttria-bearing NFSs result from the pinning of thegrain boundaries by a combined effect of solute segregation and precipitation.Although HIP and hot extrusion are commonly used to consoli-date the NFSs,anisotropic properties and processing costs are con-sidered challenging issues.Recently,spark plasma sintering (SPS)has been utilized to sinter the powder at a higher heating rate,low-er temperature and shorter dwell time.This can be done by apply-ing a uniaxial pressure and direct current pulses simultaneously to a powder sample contained in a graphite die [10].Except for a few studies on consolidation of simple systems such as Fe–9Cr–0.3/0.6Y 2O 3[11]and Fe–14Cr–0.3Y 2O 3[10],the SPS process has not been extensively utilized to consolidate the NFSs with complex compositions.Recently,the role of Ti and Y 2O 3in processing of Fe–16Cr–3Al–1Ti–0.5Y 2O 3(wt.%)via MA and SPS was investigated by Allahar et al.[12].A bimodal grain size distribution in conjunc-tion with Y–Ti–O-enriched NCs were obtained [12,13].In this study,Fe–14Cr (wt.%)was designed as the base or matrix alloy,and then Ti,La 2O 3and Mo were sequentially added to the ferritic matrix and ball milled.This approach allowed us to study the effect of individual and combined addition of solutes on the formation of NCs along with other microstructural evolutions.Furthermore,SPS instead of other traditional consolidation methods was used to consolidate the NFS powder.The mixture/10.1016/j.jallcom.2014.01.2430925-8388/Ó2014Elsevier B.V.All rights reserved.⇑Corresponding author.Tel.:+12088855964;fax:+12088857462.E-mail address:icharit@ (I.Charit).of Fe–Cr–Ti–Mo powder with Y2O3was also processed and characterized in a similar manner for comparison with the rest of the developed alloys.2.ExperimentalThe chemical compositions of all the developed alloys along with their identi-fying names in this study are given in Table1.High energy ball milling was per-formed in a SPEX8000M shaker mill for10h using Ar atmosphere with the milling media as steel balls of8mm in diameter and a ball to powder ratio(BPR) of10:1.A Dr.Sinter Lab SPS-515S was used to consolidate the as-milled powder at different temperatures(850,950and1050°C)for7min using the pulse pattern 12–2ms,a heating rate of100°C/min and a pressure of80MPa.The SPSed samples were in the form of disks with8mm in height and12mm in diameter.The density of the sintered specimens was measured by Archimedes’method. Vickers microhardness tests were performed using a Leco LM100microhardness tester operated at a load of1000g–f(9.8N).A Fischione Model110Twin-Jet Elec-tropolisher containing a mixture of CH3OH–HNO3(80:20by vol.%)as the electrolyte and operated at aboutÀ40°C was used to prepare specimens for transmission elec-tron microscopy(TEM).A FEI Tecnai TF30–FEG STEM operating at300kV was used. The energy dispersive spectroscopy(EDS)attached with the STEM was used to roughly examine the chemical composition of the particles.A Quanta3D FEG instrument with a Ga-ion source focused ion beam(FIB)was used to prepare spec-imens for atom probe tomography(APT)studies on14L,14LMT and14YMT sam-ples.The APT analysis was carried out using a CAMECA LEAP4000X HR instrument operating in the voltage mode at50–60K and20%of the standing volt-age pulse fraction.The atom maps were reconstructed using CAMECA IVAS3.6soft-ware and the maximum separation algorithm to estimate the size and chemical composition of NCs.This was applied to APT datasets each containing20–30million ions for each specimen.Lower evaporationfield of the nanoparticles and trajectory aberrations caused estimation of higher Fe atoms in the nanoclusters.Although the contribution of Fe atoms from the matrix was examined here,the matrix-correction was not addressed in this study.3.Results and discussionThe TEM brightfield micrographs for the various alloys SPSed at 950°C for7min are illustrated in Fig.1a–d.The microstructure of 14Cr alloy shown in Fig.1a revealed a complex microstructure with submicron subgrain-like structures,relatively high density of dislocations and low number density of oxide nanoparticles. The nanoparticles were larger(25–65nm)than the other SPSed al-loys and found to have chemical compositions close to Cr2O3and FeCr2O4as analyzed by energy dispersive spectroscopy.The microstructure of the consolidated14L alloy is shown in Fig.1b.The microstructure consisted of more ultrafine grains (<1l m but>100nm),a few nanograins with sharp boundaries and a higher number of nanoparticles mainly in the grain interiors. The number density of nanoparticles was higher than that of14Cr alloy shown in Fig.1a but lower than14LMT(Fig.1c)and14YMT (Fig.1d).In14L alloy,the nanoparticles with2–11nm in diameter were found inside the grains(hard to be observed at magnification given in Fig.1b and micrographs taken at higher magnifications was used for this purpose)whereas the nanoparticles with 50–80nm in diameter were located at the grain boundary regions. The particles on the boundaries are likely to be mainly Cr2O3and LaCrO3,but the chemical analysis of those smallest particles could not be done precisely due to the significant influence of the ferritic matrix.Fig.1c shows the microstructure of the SPSed14LMT alloy, consisting of both ultrafine grains(as defined previously)and nanograins(6100nm).The nanoparticles present in the micro-structure were complex oxides of Fe,Cr and Ti.The nanoparticles with faceted morphology and smaller than10nm in diameter were enriched in La and Ti.No evidence of stoichiometric La2TiO5or La2Ti2O7particles was observed based on the EDS and diffraction data.A similar type of microstructure was revealed in the SPSed 14YMT alloy as shown in Fig.1d.The particle size distribution histograms of the14Cr,14L, 14LMT and14YMT alloys are plotted in Fig.2a–d,respectively. Approximately1000particles were sampled from each alloy to de-velop the histograms.The average particle size decreased in order of14Cr,14L,14LMT and14YMT.The highest fraction of the particle size as shown in the histograms of14Cr,14L,14LMT and14YMT was found to be associated with25±5nm(18±2.5%),10±5nm (28±3%),5±1nm(40±6%)and5±1nm(46±5%)in diameter, respectively.The number density of nanoparticles smaller than 5±1nm was higher in14YMT than14LMT alloy.The3-D APT maps for14L alloy revealed a number density (%3Â1022mÀ3)of CrO–La–O-enriched NCs.The average Guinier radius of these NCs was1.9±0.6nm.The average composition of the NCs in14L was estimated by using the maximum separation algorithm to be Fe–17.87±3.4Cr–32.61±3.2O–8.21±1.1La(at.%).A higher number density(%1.4Â1024mÀ3)and smaller NCs with average Guinier radius of 1.43±0.20nm were observed in the APT maps for14LMT alloy as shown in Fig.3a.The NCs were Cr–Ti–La–O-enriched with the average composition of Fe–10.9±2.8Cr–30.9±3.1O–17.3±2.5Ti–8.2±2.2La(at.%).According to the LEAP measurements,the chemical composition of NCs dif-fered considerably from stoichiometric oxides.A large amount of Fe and Cr was detected inside the NCs,and La/Ti and La/O ratios were not consistent with La2TiO5or La2Ti2O7as expected based on thermodynamic calculations,rather the ratios were sub-stoichi-ometric.The3-D APT maps for14YMT alloy were similar to14YMT alloy as shown in Fig.3b.The NCs with an average radius of 1.24±0.2nm and a number density of1.5Â1024mÀ3were Cr–Ti–Y–O-enriched.The chemical composition of NCs was estimated close to Fe–8.52±3.1Cr–37.39±4.5O–24.52±3.1Ti–10.95±3.1Y (at.%).The matrix-corrected compositions are currently being ana-lyzed and will be reported in a full-length publication in near future.The relative density of various alloys sintered at850–1050°C is shown in Fig.4a.Generally,a higher density was obtained in the specimens sintered at higher temperatures.At850and950°C, the density of unmilled14Cr specimen(97.2%and97.5%)was higher than the milled/SPSed14Cr(92.8%and95.5%)because the unmilled powder particles were less hard(due to absence of strain hardening)and plastically deformed to a higher degree than the milled powder leading to a higher density.Adding0.5and 0.7wt.%of La2O3and0.3wt.%Y2O3to the14Cr matrix significantly decreased the density of the specimen,especially at850and 950°C;however,adding Ti to14L and14Y improved the density to some extent.The microhardness data of various alloys processed at different temperatures are shown in Fig.4b.In general,microhardness in-creased with increasing SPS temperatures up to950°C and then decreased.Both Y and La increased the hardness due to the disper-sion hardening effect.The hardness increased at the higher content of La due to the greater effect of dispersion hardening.Adding Ti separately to the14Cr matrix improved the hardness due to theTable1The alloy compositions and processing conditions(milled for10h and SPSed at850-1050°C for7min).Alloy ID Elements(wt.%)Cr Ti La2O3Y2O3Mo Fe14Cr-unmilled140000Bal.14Cr140000Bal.14T141000Bal.14L1400.500Bal.14Y14000.30Bal.14LM1400.500.3Bal.14LT1410.500Bal.14LMT(0.3)1410.300.3Bal.14LMT1410.500.3Bal.14LMT(0.7)1410.700.3Bal.14YMT14100.30.3Bal.S.Pasebani,I.Charit/Journal of Alloys and Compounds599(2014)206–211207dispersion hardening but only at lower temperature(850°C).The coarsening of Ti-enriched particles at above850°C plausibly decreased the hardness.However,at950°C,higher hardness (457HV)was achieved by a combined addition of La and Ti toFig.2.Particle size frequency histogram for(a)14Cr,(b)14L,(c)14LMT and(d)14YMT alloys. Fig.1.TEM brightfield micrographs for various alloys(a)14Cr,(b)14L,(c)14LMT and(d)14YMT.the14Cr matrix to produce14LT.Further addition of Mo to14LT improved the hardness through solid solution strengthening in 14LMT(495HV).High dislocation density and no well-defined grain boundaries were characteristics of14Cr alloy as shown in Fig.1a.The presence of a low number density and larger oxide particles(FeCr2O4and Cr2O3)at the boundaries could not create an effective pinning effect during sintering.As a result,some of these particles became confined within the grain interiors.The coarse grains had the capacity to produce and store high density of dislocations that subsequently resulted in the strain hardening effect.The hardening mechanism in14Cr alloy can thus be attributed to greater disloca-tion activities and resulting strain hardening effect.The grain boundary or precipitation hardening cannot be the dominant mechanism because of larger particles,greater inter-particle spac-ing and weakened Zener drag effect at the temperature of sinter-ing.Such strain hardening capability in nanocrystalline Fe consolidated via SPS was reported by other researchers,too [14,15].Interestingly,the high hardness in Fe–14Cr alloy consoli-dated via SPS at1100°C for4min by Auger et al.[10]wasFig.3.Three-dimensional atom maps showing NCs for(a)14LMT–91Â34Â30nm3and(b)14YMT–93Â30Â30nm3.Fig.4.(a)The relative density and(b)microhardness values for different SPSed alloys processed at different SPS temperatures for a dwell time of7min.attributed to the formation of martensitic laths caused by higher carbon content diffusing from the die,possible Cr segregation and rapid cooling during SPS.It is noteworthy to mention that no martensite lath was observed in the consolidated14Cr alloy in the present study.The level of solutes in the bcc matrix could be much greater than the equilibrium level,associated with a large number of vacancies created during milling.Our recent study[16]has shown that high energy ball milling has a complex role in initiating nucle-ation of La–Ti–O-enriched NCs in14LMT alloy powder,with a mean radius of%1nm,a number density of3.7Â10À24mÀ3and a composition of Fe–12.11Cr–9.07Ti–4.05La(at.%).The initiation of NCs during ball milling of NFSs has also been investigated by other researchers[8,17,18].According to Williams et al.[8],due to a low equilibrium solubility of O in the matrix,the precipitation of nanoparticles is driven by an oxidation reaction,subsequently resulting in reduction of the free energy.As the SPS proceeds,the number density of NCs would decrease and larger grain boundary oxides would form with the grain structure developing simulta-neously during the sintering process[8].Formation of larger grain boundary oxides as shown in Fig.1a could have been preceded by segregation of O and Cr to grain boundaries leading to a decrease in the level of the solutes in the ferritic matrix.The initial oxides forming in a chromium-rich matrix can be Cr2O3as suggested by Williams et al.[8].However,formation of LaCrO3in14L alloy (shown in Fig.1b)was associated with a higher reduction in the free energy according to the enthalpy of formation of various oxi-des given in Table2.The presence of nanoparticles caused grain boundary pinning and subsequently stabilized the nanocrystalline grains.The high density of defects(dislocations and vacancies)in a supersaturated solid solution,such as14LMT and14YMT alloys, could dramatically increase the driving force for accelerated sub-grain formation during the initial stage of sintering.At the initial stage,the vacancies created during the milling are annihilated [8,17].Meanwhile,the temperature is not high enough to produce a significant number of thermal vacancies;subsequently,any nucleation of new NCs will be prevented.As the SPS proceeds with no nucleation of new NCs,the high concentrations of extra solutes in the matrix are thermodynamically and kinetically required to precipitate out to form larger oxide particles.The larger solute-enriched oxide particles can be formed more favorably on the grain boundaries due to the higher boundary diffusivity.On the other hand,it should be considered that there is a dynamic plastic deformation occurring within the powder particles during SPS. The interaction of larger particles and dislocations introduced by dynamic hot deformation can explain the coarsening in some grains;because larger particles could not effectively pin the dislo-cations and the grain boundary migration could be facilitated fol-lowing the orientation with lower efficiency of Zener drag mechanism[19].Once the extra solutes present in the matrix pre-cipitated out,the microstructure will remain very stable because of the grain boundary pinning by triple-junctions of the grain bound-aries themselves[20],along with the high density of NCs and other ultrafine oxide particles[8].Further coarsening of the grains will be prevented even for longer dwell times at950°C.Therefore,a bi-modal grain size distribution emerged.The hardening of14LMT and14YMT alloys were attributed to a combined effect of solid solution strengthening,Hall-Petch strengthening and precipitation hardening.Based on the APT studies of the as-milled powder[16]and for-mation mechanism of the oxide particles suggested by Williams et al.[8]it could be speculated that in14LMT and14YMT alloys, Cr–O species formfirst and then absorb Ti and La/Y.This is associ-ated with a change in the interfacial energy of Cr–O species even though it is not thermodynamically the most favorable oxide.It has been established that the driving force for the oxide precipi-tates to form is the low solubility limit of oxygen in the ferritic ma-trix.The change in free energy due to oxidation reaction and nucleation of oxide nanoparticles is the leading mechanism[8].The majority of the oxygen required to generate the oxide nano-particles may be provided from the surface oxide during milling process.Furthermore,higher concentrations of Cr led to greater nucleation of Cr–O by influencing the kinetics of oxide formation. Concentrations and diffusivities of the oxide species along with the energy barrier for nucleation will control the nucleation of oxide nanoparticles.After the Cr–O formed during sintering,the Ti–O and Y/La-enriched clusters could form.The sub-stoichiome-tric NCs in14LMT and14YMT alloys were not due to insufficient level of O in the matrix[8].Formation of stoichiometric Y2Ti2O7 and Y2TiO5requires very high temperatures[8],which were outside the scope of this study.4.ConclusionThe SPSed Fe–14Cr alloy was found to have a higher hardness at room temperature due to the strain hardening effect.The stability of its microstructure at high temperatures was improved by addi-tion of La forming the Cr–La–O-enriched NCs.Adding La and Ti to Fe–14Cr matrix significantly improved the mechanical behavior and microstructural stability further due to the high number density of Cr–Ti–La–O-enriched NCs in14LMT alloy.It is demon-strated that the potential capability of La in developing new NFSs is promising but further investigations on their thermal and irradiation stability will still be required.AcknowledgementThis work was supported partly by the Laboratory Directed Research and Development Program of Idaho National Laboratory (INL),and by the Advanced Test Reactor National Scientific User Facility(ATR NSUF),Contract DE-AC07-05ID14517.The authors gratefully acknowledge the assistance of the staff members at the Microscopy and Characterization Suite(MaCS)facility at the Center for Advanced Energy Studies(CAES).References[1]M.J.Alinger,G.R.Odette,G.E.Lucas,J.Nucl.Mater.307–311(2002)484.[2]R.L.Klueh,J.P.Shingledecker,R.W.Swindeman,D.T.Hoelzer,J.Nucl.Mater.341(2005)103.[3]M.J.Alinger,G.R.Odette,D.T.Hoelzer,J.Nucl.Mater.329–333(2004)382.[4]M.J.Alinger,G.R.Odette,D.T.Hoelzer,Acta Mater.57(2009)392.Table2The standard enthalpies of formation of various oxide compounds at25°C[8,21,22].Element CompositionÀD H f(kJ molÀ1(oxide))Cr Cr2O31131CrO2583Fe Fe3O41118Fe2O3822Ti TiO543TiO2944Ti2O31522Ti3O52475Y Y2O31907YCrO31493Y2Ti2O73874La La2O31794La2Ti2O73855LaCrO31536210S.Pasebani,I.Charit/Journal of Alloys and Compounds599(2014)206–211[5]G.R.Odette,M.L.Alinger,B.D.Wirth,Annu.Rev.Mater.Res.38(2008)471.[6]ai,T.Okuda,M.Fujiwara,T.Kobayashi,S.Mizuta,H.Nakashima,J.Nucl.Sci.Technol.39(2002)872.[7]ai,M.Fujiwara,J.Nucl.Mater.307–311(2002)749.[8]C.A.Williams,P.Unifantowicz,N.Baluc,G.D.Smith,E.A.Marquis,Acta Mater.61(2013)2219.[9]ler,C.M.Parish,Mater.Sci.Technol.27(2011)729.[10]M.A.Auger,V.De Castro,T.Leguey,A.Muñoz,Pareja,R,J.Nucl.Mater.436(2013)68.[11]C.Heintze,M.Hernández-Mayoral, A.Ulbricht, F.Bergner, A.Shariq,T.Weissgärber,H.Frielinghaus,J.Nucl.Mater.428(2012)139.[12]K.N.Allahar,J.Burns,B.Jaques,Y.Q.Wu,I.Charit,J.I.Cole,D.P.Butt,J.Nucl.Mater.443(2013)256.[13]Y.Q.Wu,K.N.Allahar,J.Burns,B.Jaques,I.Charit,D.P.Butt,J.I.Cole,Cryst.Res.Technol.(2013)1,/10.1002/crat.201300173.[14]K.Oh-Ishi,H.W.Zhang Hw,T.Ohkubo,K.Hono,Mater.Sci.Eng.A456(2007)20.[15]B.Srinivasarao,K.Ohishi,T.Ohkubo,K.Hono,Acta Mater.57(2009)3277.[16]S.Pasebani,I.Charit,Y.Q.Wu, D.P.Butt,J.I.Cole,Acta Mater.61(2013)5605.[17]M.L.Brocq,F.Legendre,M.H.Mathon,A.Mascaro,S.Poissonnet,B.Radiguet,P.Pareige,M.Loyer,O.Leseigneur,Acta Mater.60(2012)7150.[18]M.Brocq,B.Radiguet,S.Poissonnet,F.Cuvilly,P.Pareige,F.Legendre,J.Nucl.Mater.409(2011)80.[19]H.K.D.H.Bhadeshia,Mater.Sci.Eng.A223(1997)64.[20]H.K.D.H.Bhadeshia,Mater.Sci.Technol.16(2000)1404.[21]W.Gale,T.Totemeier,Smithells Metals Reference Book,Amsterdam,Holland,2004.[22]T.J.Kallarackel,S.Gupta,P.Singh,J.Am.Ceram.Soc.(2013)1,http:///10.1111/jace.12435.S.Pasebani,I.Charit/Journal of Alloys and Compounds599(2014)206–211211。
Ga2O3
第52卷第7期 辽 宁 化 工 Vol.52，No. 7 2023年7月 Liaoning Chemical Industry July，2023基金项目： 武汉工程大学研究生创新基金（项目编号：CX2021177）。
收稿日期： 2022-11-12Ga 2O 3/p -GaN 异质结自供电日盲紫外光探测器的制备与光电性能研究孙雅迪，王超，付秋明（武汉工程大学 湖北省等离子体化学与新材料重点实验室 材料科学与工程学院，湖北 武汉 430205）摘 要：采用水热法在p -GaN 衬底上生长Ga 2O 3纳米棒阵列，构建了Ga 2O 3/p -GaN 异质结自供电日盲紫外光探测器。
首先对异质结的形貌和结构性能进行了研究，并进一步对异质结紫外光探测器的伏安特性和紫外光探测性能进行了探索。
结果表明在0 V 偏压和254 nm 紫外光照下，器件表现出明显的自供电日盲紫外光响应，响应度为718.8 mA/W，并具有良好的稳定性和重复性。
结合异质结能带理论对器件的自供电紫外光响应机理进行了讨论。
关 键 词：氧化镓；异质结；自供电；日盲紫外光探测器中图分类号：TQ133.51 文献标识码： A 文章编号： 1004-0935（2023）07-0954-04大气层中的臭氧层对紫外光具有吸收与散射作用，这使得太阳光中波长在200~280 nm 波段的紫外光几乎到达不了地球表面，我们将这个波段的紫外光称为日盲紫外光。
因此在大气层内的地球表面，由于没有太阳辐射的干扰，日盲紫外光探测器具备出色的抗干扰能力，较高的灵敏度等优点，常被应用于短波通讯、火灾预警、导弹追踪等方面[1-4]。
目前，常见的日盲紫外光探测器大多是光电探测器，它利用光电效应，将入射的光学信号转化为电学信号，再被检测仪器接收，这类探测器还被分为光电导型探测器和光伏型探测器[5-6]。
相较于光电导型探测器，光伏型探测器中由于肖特基结或PN 结的存在，光生载流子会在内建电场的作用下分离，这使得器件可以在没有外加电源的情况下工作，这就是自供电特性。
铜材料与镓基液态金属相容性的研究进展
铜材料与镓基液态金属相容性的研究进展丁建伟，邱长军，杨帆（南华大学机械工程学院，湖南衡阳421001）摘要：铜合金与镓基液态金属接触时会发生较强的腐蚀现象，严重影响了镓基液态金属优质冷却性能的发挥。
文中综述了铜材料在镓基液态金属中的腐蚀及涂层防腐的研究进展，重点从温度因素对腐蚀行为及机理的影响方面进行了综述。
同时，指出了目前镓基液态金属中铜材料的腐蚀防护方面存在的主要问题及今后的发展方向。
关键词：铜；镓基液态金属；腐蚀；涂层中图分类号:TG17文献标志码:A文章编号：1002-2333（2021）04-0013-03 Research Progress on Compatibility of Copper Material with Gallium Base Liquid MetalDING Jianwei,QIU Changjun,YANG Fan（School of Mechanical Engineering,University of South China,Hengyang421001,China）Abstract:The strong corrosion phenomenon occurs when the copper alloy comes into contact with gallium base liquid metal,which seriously affects the excellent cooling performance of gallium base liquid metal.This paper reviews the research progress of copper corrosion and coating corrosion protection in gallium base liquid metal,with emphasis on the influence of temperature on corrosion behavior and mechanism.At the same time,the main problems existing in the corrosion protection of copper materials in liquid gallium base metal and the future development direction are pointed out. Keywords:copper;gallium base liquid metal;corrosion;coating0引言目前已知的熔点低于或接近室温的金属元素有钫（Fr）、铯（Cs）、铷（Rb）、汞（Hg）和镓（Ga）。
基于分形方法的YSZ热障涂层有效热导率分析
第33卷第3期中国表面工程Vol．33No．32020年6月CHINA SUＲFACE ENGINEEＲINGJune 2020收稿日期：2019-09-09；修回日期：2020-03-25通信作者：丁坤英（1981—），男（汉），副教授，博士；研究方向：热喷涂；E-mail ：dingkunying@126．com 基金项目：国家自然科学基金（51501222）；民航局科技项目（MHＲD2*******）Fund ：Supported by National Natural Science Foundation of China （51501222）and Science and Technology Program of Civil Aviation of China（MHＲD2*******）引用格式：丁坤英，李志远，王者，等．基于分形方法的YSZ 热障涂层有效热导率分析［J ］．中国表面工程，2020，33（3）：104-110．DING K Y ，LI Z Y ，WANG Z ，et al．Analysis of YSZ effective thermal conductivity based on fractal theory ［J ］．China Surface Engi-neering ，2020，33（3）：104-110．doi ：10.11933/j.issn．10079289.20190909001基于分形方法的YSZ 热障涂层有效热导率分析丁坤英，李志远，王者，程涛涛（中国民航大学天津市民用航空器适航与维修重点实验室，天津300300）摘要：陶瓷基热障涂层具有优异的阻热性能、耐热腐蚀性能以及热稳定性能，在航空发动机热端部件中广泛使用。
利用大气等离子喷涂方法制备ZrO 2－8%Y 2O 3（YSZ ）涂层，利用聚苯酯（PHB ）调节涂层的孔隙形态和含量，利用扫描电镜（SEM ）和图像软件分析涂层的截面形貌，计算了孔隙的分形维数，建立了基于分形维数的有效热导率计算方法，优化了热导率与涂层孔隙的定量关系。
铜矿石提高回收率的选矿新工艺探究
采矿工程M ining engineering 铜矿石提高回收率的选矿新工艺探究杨 宇（紫金（厦门）工程设计有限公司，福建 厦门 ３６１００９）摘 要：我国的铜矿资源虽然十分丰富，但人均占有量较低，并且我国的铜矿资源中还有很多低品位、复杂难选的铜矿资源，在当前铜矿资源日益枯竭的背景下，如何对这些特殊的铜矿资源实现进一步的开发利用有着非常重要的现实意义。
这就需要相应的开发企业能够使用更为先进、合理的选矿技术，同时进一步提升铜矿石中铜的回收效率，这样不仅有利于提高企业的经济效益，同时还能提高铜矿资源的利用效率，避免了一些不必要的浪费现象，有助于促进我国国民经济的进一步发展。
本文以某铜矿为例，在对该铜矿的矿石性质进行分析的基础上，对当前使用比较广泛的几种选矿方法进行了对比分析，并通过相应的试验分析得出了新工艺的应用价值，以期对促进我国铜矿事业的更好发展有所裨益。
关键词：铜矿石；回收率；选矿新工艺中图分类号：ＴＤ９５２ 文献标识码：Ａ 文章编号：１００２－５０６５（２０２０）１９－００５３－２Research on new mineral processing technology for improving recovery of copper oreYANG Yu（Ｚｉｊｉｎ （Ｘｉａｍｅｎ） Ｅｎｇｉｎｅｅｒｉｎｇ Ｄｅｓｉｇｎ Ｃｏ．， Ｌｔｄ，Ｘｉａｍｅｎ ３６１００９，Ｃｈｉｎａ）Abstract: Ａｌｔｈｏｕｇｈ Ｃｈｉｎａ＇ｓ ｃｏｐｐｅｒ ｒｅｓｏｕｒｃｅｓ ａｒｅ ｖｅｒｙ ｒｉｃｈ， ｂｕｔ ｔｈｅ ｐｅｒ ｃａｐｉｔａ ｓｈａｒｅ ｉｓ ｌｏｗ， ａｎｄ ｔｈｅｒｅ ａｒｅ ｍａｎｙ ｌｏｗ－ｇｒａｄｅ， ｃｏｍｐｌｅｘ ａｎｄ ｒｅｆｒａｃｔｏｒｙ ｃｏｐｐｅｒ ｒｅｓｏｕｒｃｅｓ ｉｎ Ｃｈｉｎａ＇ｓ ｃｏｐｐｅｒ ｒｅｓｏｕｒｃｅｓ． Ｕｎｄｅｒ ｔｈｅ ｂａｃｋｇｒｏｕｎｄ ｏｆ ｉｎｃｒｅａｓｉｎｇｌｙ ｅｘｈａｕｓｔｅｄ ｃｏｐｐｅｒ ｒｅｓｏｕｒｃｅｓ， ｈｏｗ ｔｏ ｆｕｒｔｈｅｒ ｄｅｖｅｌｏｐ ａｎｄ ｕｔｉｌｉｚｅ ｔｈｅｓｅ ｓｐｅｃｉａｌ ｃｏｐｐｅｒ ｒｅｓｏｕｒｃｅｓ ｈａｓ ｖｅｒｙ ｉｍｐｏｒｔａｎｔ ｐｒａｃｔｉｃａｌ ｓｉｇｎｉｆｉｃａｎｃｅ． Ｔｈｉｓ ｒｅｑｕｉｒｅｓ ｔｈｅ ｃｏｒｒｅｓｐｏｎｄｉｎｇ ｄｅｖｅｌｏｐｍｅｎｔ ｅｎｔｅｒｐｒｉｓｅｓ ｔｏ ｂｅ ａｂｌｅ ｔｏ ｕｓｅ ｍｏｒｅ ａｄｖａｎｃｅｄ ａｎｄ ｒｅａｓｏｎａｂｌｅ ｂｅｎｅｆｉｃｉａｔｉｏｎ ｔｅｃｈｎｏｌｏｇｙ， ａｎｄ ｆｕｒｔｈｅｒ ｉｍｐｒｏｖｅ ｔｈｅ ｃｏｐｐｅｒ ｒｅｃｏｖｅｒｙ ｅｆｆｉｃｉｅｎｃｙ ｉｎ ｃｏｐｐｅｒ ｏｒｅ， ｗｈｉｃｈ ｉｓ ｎｏｔ ｏｎｌｙ ｃｏｎｄｕｃｉｖｅ ｔｏ ｉｍｐｒｏｖｉｎｇ ｔｈｅ ｅｃｏｎｏｍｉｃ ｂｅｎｅｆｉｔｓ ｏｆ ｅｎｔｅｒｐｒｉｓｅｓ， ｂｕｔ ａｌｓｏ ｉｍｐｒｏｖｉｎｇ ｔｈｅ ｕｔｉｌｉｚａｔｉｏｎ ｅｆｆｉｃｉｅｎｃｙ ｏｆ ｃｏｐｐｅｒ ｒｅｓｏｕｒｃｅｓ， ａｖｏｉｄｉｎｇ ｓｏｍｅ ｕｎｎｅｃｅｓｓａｒｙ ｗａｓｔｅ ｐｈｅｎｏｍｅｎｏｎ， ａｎｄ ｐｒｏｍｏｔｉｎｇ ｔｈｅ ｆｕｒｔｈｅｒ ｄｅｖｅｌｏｐｍｅｎｔ ｏｆ Ｃｈｉｎａ＇ｓ ｎａｔｉｏｎａｌ ｅｃｏｎｏｍｙ． Ｔａｋｉｎｇ ａ ｃｏｐｐｅｒ ｍｉｎｅ ａｓ ａｎ ｅｘａｍｐｌｅ， ｂａｓｅｄ ｏｎ ｔｈｅ ａｎａｌｙｓｉｓ ｏｆ ｔｈｅ ｏｒｅ ｐｒｏｐｅｒｔｉｅｓ ｏｆ ｔｈｅ ｃｏｐｐｅｒ ｍｉｎｅ， ｔｈｉｓ ｐａｐｅｒ ｍａｋｅｓ ａ ｃｏｍｐａｒａｔｉｖｅ ａｎａｌｙｓｉｓ ｏｆ ｓｅｖｅｒａｌ ｍｉｎｅｒａｌ ｐｒｏｃｅｓｓｉｎｇ ｍｅｔｈｏｄｓ ｗｉｄｅｌｙ ｕｓｅｄ ａｔ ｐｒｅｓｅｎｔ， ａｎｄ ｏｂｔａｉｎｓ ｔｈｅ ａｐｐｌｉｃａｔｉｏｎ ｖａｌｕｅ ｏｆ ｔｈｅ ｎｅｗ ｔｅｃｈｎｏｌｏｇｙ ｔｈｒｏｕｇｈ ｔｈｅ ｃｏｒｒｅｓｐｏｎｄｉｎｇ ｅｘｐｅｒｉｍｅｎｔａｌ ａｎａｌｙｓｉｓ， ｓｏ ａｓ ｔｏ ｐｒｏｍｏｔｅ ｔｈｅ ｂｅｔｔｅｒ ｄｅｖｅｌｏｐｍｅｎｔ ｏｆ ｃｏｐｐｅｒ ｉｎｄｕｓｔｒｙ ｉｎ Ｃｈｉｎａ．Keywords: ｃｏｐｐｅｒ ｏｒｅ； ｒｅｃｏｖｅｒｙ； ｎｅｗ ｍｉｎｅｒａｌ ｐｒｏｃｅｓｓｉｎｇ ｔｅｃｈｎｏｌｏｇｙ某铜矿随着开采时间的不断推移以及开采力度的不断增大，使得了当前该铜矿也由最初的露天开采转变成了地下开采。
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Accepted ManuscriptEffects of Y2O3 on the property of copper based contact materialsZhen Mu, Hao-Ran Geng, Meng-Meng Li, Guang-Lin Nie, Jin-Feng LengPII:S1359-8368(13)00091-7DOI:http://dx.doi.org/10.1016/j.compositesb.2013.02.036Reference:JCOMB 2271
To appear in:Composites: Part BReceived Date:27 September 2012Revised Date:19 January 2013Accepted Date:26 February 2013
Please cite this article as: Mu, Z., Geng, H-R., Li, M-M., Nie, G-L., Leng, J-F., Effects of Y2O3 on the property of
copper based contact materials, Composites: Part B (2013), doi: http://dx.doi.org/10.1016/j.compositesb.2013.02.036
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customerswe are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, andreview of the resulting proof before it is published in its final form. Please note that during the production processerrors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
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Effects of Y2O3 on the property of copper based contact materials Zhen Mu, Hao-Ran Geng1, Meng-Meng Li, Guang-Lin Nie, Jin-Feng Leng Abstract The copper based electric contact materials with multicomponent substance were obtained by powder metallurgy. The hardness and density of the samples increase with adding proper amount of Y2O3. Adding 1.5 wt. % Y2O3 the hardness of the sample reaches the maximum and the density of sample reaches the maximum by adding 2 wt. % Y2O3. In this paper, the effects of addition of Y2O3 on the performance of copper based contact materials were studied by metallographic microscope, XRD, SEM in details. Moreover, the mechanism of the effects was discussed.
Keywords：A.Metal-matrix composites; B.Electrical properties; D.Optical microscopy Physical methods of analysis; E. Sintering; 1. Introduction Electric contact materials are used in electric switches which switch on and off the current, therefore the performances of those materials have important effects on the running stability and service life of instruments [1,2]. Opening or breaking a contact pair switching system usually results in an arc being drawn between the contact pair. Due to electric arc energy, the surface of contact material would come up warming, melting, vaporizing, splashing and solidifying etc. metallurgy process. Therefore contact materials not only need excellent electric contact properties, but also excellent mechanical properties and chemical stability. At present, electrical contact materials used in switching devices are commonly made from silver alloys because of the properties of minimizing contact welding and arc erosion during operation [3-7]. But silver is very expensive and is very difficult to be recycled from the contact materials, so developing a new material which does not contain silver is very desirable. The electrical conductivity and thermal conductivity of copper are similar to those of silver and the resource of copper is abundant, so copper can become the substitute of sliver [8]. Cu-based contact material is often applied to vacuum breaker or high voltage normally closed switch. Copper tends to be oxidized and the oxidized derivative is nonconductive. If copper is used for contact material, its oxidized derivatives will cause the contact resistance to rise sharply, and then the arc erosion become serious and the lifetime get shorten when the switch is operated. Based on the performance requirement of contact materials, this paper developed a new high-performance copper based contact material by powder metallurgy. Y2O3 was used as the dispersion-strengthening phase of the copper alloy owning to the good wettability between the liquid copper and Y2O3 phase and the good chemical stability [9]. The effects of Y2O3 on the performances of copper based materials were
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