調(diào)制比對(duì)磁控濺射法生長(zhǎng)DLC/WSx多層膜微結(jié)構(gòu)和力學(xué)性能的影響

鄭曉華，林玲玲，常新新，王貢啟，楊芳兒

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調(diào)制比對(duì)磁控濺射法生長(zhǎng)DLC/WS多層膜微結(jié)構(gòu)和力學(xué)性能的影響

鄭曉華，林玲玲，常新新，王貢啟，楊芳兒

(浙江工業(yè)大學(xué) 材料科學(xué)與工程學(xué)院，杭州 310014)

采用磁控濺射法在200 ℃Si(100)基體上交替沉積WS和類金剛石碳膜(DLC)制備不同調(diào)制比的DLC/WS多層膜(周期為10 nm)。利用掃描電鏡(SEM)、能譜儀(EDS)、X射線衍射儀(XRD)、X射線光電子譜(XPS)等手段分析調(diào)制比對(duì)多層膜成分、微觀結(jié)構(gòu)及界面的影響。利用薄膜應(yīng)力測(cè)試儀、納米壓痕儀、涂層附著力劃痕儀和球盤式摩擦磨損試驗(yàn)機(jī)等測(cè)試多層膜的力學(xué)性能及大氣中的摩擦磨損性能。結(jié)果表明：DLC/WS多層膜結(jié)構(gòu)致密而平整，界面強(qiáng)化效應(yīng)明顯，膜中WS均為非晶結(jié)構(gòu)。隨著調(diào)制比增大，多層膜的(S)/(W)由0.77增大至1.08，硬度先降低后升高，膜內(nèi)壓應(yīng)力逐漸減小，結(jié)合力先增大后減小，摩擦因數(shù)由0.307降至0.171，磨損率逐漸上升。調(diào)制比為1:39的多層膜性能最優(yōu)，硬度可達(dá)11.4 GPa，磨損率低至1.17×10?15 m3?N?1?m?1，顯著優(yōu)于純WS薄膜的。

WS2；類金剛石碳；多層膜；調(diào)制比；顯微組織；摩擦；磨損

過渡族金屬硫化物(MS)由于其特殊的六方層狀結(jié)構(gòu)，層與層之間的剪切強(qiáng)度很低，使其擁有優(yōu)異的潤(rùn)滑特性[1?2]。其中，WS2因其在真空環(huán)境下摩擦因數(shù)低、工作溫度高、耐磨性能好等優(yōu)點(diǎn)而被廣泛應(yīng)用于機(jī)械加工和航天航空等領(lǐng)域中[3?4]。然而，純WS2薄膜結(jié)構(gòu)疏松，其硬度及承載能力有限，且在潮濕環(huán)境中易潮解和氧化形成WO3，致使?jié)櫥阅芗眲∠?降[5?6]。

研究表明，在WS2薄膜中摻入單質(zhì)金屬如Ti[7?8]，Ag[9]、Cr[10]、Ni[11?12]等元素，可以改善薄膜的抗氧化性和耐磨性；而在WS2薄膜中添加非金屬元素如C、N以及化合物[13?17]制成復(fù)合薄膜，其硬度、彈性模量、耐磨性等也得到了明顯提升，如WU等[18]采用磁控濺射和脈沖激光沉積技術(shù)制備了WC/DLC/WS2納米復(fù)合膜(Diamond like carbon，DLC)，發(fā)現(xiàn)復(fù)合膜主要呈非晶結(jié)構(gòu)，表面平整致密，具有很好的摩擦學(xué)性能和環(huán)境適應(yīng)性。此外，納米多層化亦是薄膜性能改良的有效方法之一[19?22]，由于納米多層膜的界面強(qiáng)化效應(yīng)有助于提高薄膜的硬度、韌性、耐磨性和抗氧化性能，特別是在軟硬交替的多層膜體系中。ZHU等[23]采用磁控濺射和低溫離子滲硫復(fù)合技術(shù)制備了WS2/MoS2多層膜，發(fā)現(xiàn)WS2和MoS2之間產(chǎn)生交互作用，提高薄膜致密度，增強(qiáng)抗氧化性，并且多層膜較純WS2膜具有較低的摩擦系數(shù)和較優(yōu)的耐磨性。GONG等[24]采用等離子體化學(xué)氣相沉積和中頻脈沖非平衡磁控濺射相結(jié)合的方法制備了類石墨烯/MoS2復(fù)合多層膜，發(fā)現(xiàn)具有分層結(jié)構(gòu)的納米多層膜摩擦學(xué)性能較好，在潮濕空氣中可達(dá)到超滑(摩擦因數(shù)約0.004)。楊芳兒等[25?26]制備了不同層厚比和不同調(diào)制周期的WS/a-C多層膜，發(fā)現(xiàn)多層膜結(jié)構(gòu)致密，表面平整，其硬度、結(jié)合力以及在大氣中的耐磨性有所改善。劉京京等[27]制備了CrA1N/WS2納米多層膜，發(fā)現(xiàn)六方結(jié)構(gòu)的WS2在CrA1N的模板作用下會(huì)轉(zhuǎn)變?yōu)锽1-NaCl型面心立方結(jié)構(gòu)并與CrA1N層發(fā)生共格外延生長(zhǎng)，使薄膜的力學(xué)性能和耐磨性得到強(qiáng)化。WATANABE等[28]采用磁控濺射法制備了WS2/MoS2納米多層膜，結(jié)果表明多層膜具有超晶格結(jié)構(gòu)，與單一薄膜相比，表現(xiàn)出良好的力學(xué)性能以及較長(zhǎng)的使用壽命；XU等[29]對(duì)MoS2/Mo-S-C納米多層膜的研究發(fā)現(xiàn)，所制備的多層膜中MoS2呈現(xiàn)出明顯的(002)晶面擇優(yōu)生長(zhǎng)，并且多界面設(shè)計(jì)可以改變相鄰子層的結(jié)構(gòu)，使薄膜的韌性和耐磨性得到很大改善。

鑒于類金剛石碳膜(DLC)的高硬度、在大氣環(huán)境中的優(yōu)異摩擦學(xué)性能[30?31]以及納米多層界面效應(yīng)對(duì)薄膜性能的有益作用，本文作者嘗試構(gòu)筑DLC/WS納米多層膜，通過研究不同調(diào)制比DLC/WS納米多層膜的成分、結(jié)構(gòu)、力學(xué)和摩擦磨損性能，闡明DLC膜層與WS膜層之間的作用機(jī)理，為理解DLC/WS納米多層膜的性能奠定理論和實(shí)驗(yàn)基礎(chǔ)，也為進(jìn)一步提升WS2薄膜在大氣環(huán)境中的耐磨性，拓展其應(yīng)用范圍提供實(shí)驗(yàn)依據(jù)和新思路。

1 實(shí)驗(yàn)

采用磁控濺射法交替濺射WS2靶和石墨靶，在Si(100)基體上沉積DLC/WS多層膜，通過控制基體在WS2靶和石墨靶上方的停留時(shí)間，獲得調(diào)制周期約為10 nm、調(diào)制比DLC/WSx(單個(gè)周期內(nèi)DLC膜和WS膜的厚度之比)分別為1:39、1:19、1:9、3:20、1:4(分別編號(hào)為樣品2~6)的DLC/WS多層膜，薄膜總厚度約為500 nm(50個(gè)周期)，且先沉積WS層。鍍膜前先將拋光的基體(單晶硅片，P型，á100?晶向)放入體積分?jǐn)?shù)為10%氫氟酸溶液中清洗5min，再分別用丙酮和無水乙醇各清洗15min，烘干后裝入JPG?450型真空鍍膜機(jī)，腔體內(nèi)的本底真空度為1.5×10?3Pa，隨后采用如下條件進(jìn)行濺射：靶基距70 mm，濺射氣壓0.6 Pa，偏壓?50 V，基體溫度200 ℃，WS2靶功率60 W，石墨靶功率65 W。另外，在相同工藝條件下制備了厚度約為500 nm的純WS膜(樣品1)和DLC膜(樣品7)，以便進(jìn)行對(duì)比分析。

采用型號(hào)為Bruker D8 Advance的Х射線衍射儀(XRD)分析多層膜的晶體結(jié)構(gòu)，Cu靶K射線(=0.154 056 nm)，步長(zhǎng)0.033 (°)/s，掃描角度6°~63°。用型號(hào)為∑IGMA的蔡司場(chǎng)發(fā)射掃描電鏡(SEM)觀察DLC/WS多層膜磨損前后的表面形貌，并用電鏡自帶的能譜儀(EDS)分析多層膜的化學(xué)成分。采用型號(hào)為AXIS ULTRA DLD的X射線光電子能譜儀(XPS)測(cè)定元素的光電子譜，激發(fā)源為Al靶K單色輻射(=1486.7 eV)，功率為45 W，步長(zhǎng)50 meV，通能20 eV，所得譜線在XPSPEAK軟件中用Shirley法扣除背底，然后用洛倫茲?高斯函數(shù)進(jìn)行擬合。采用型號(hào)為L(zhǎng)abRAM HR UV的激光拉曼光譜儀對(duì)DLC膜樣品的拉曼光譜進(jìn)行分析，激光波長(zhǎng)為632.8 nm，所得譜線用線性插值法扣除背底，用洛倫茲?高斯函數(shù)進(jìn)行擬合。采用型號(hào)為SuPro FST 150的薄膜應(yīng)力測(cè)試儀[32]測(cè)量基體鍍膜前后曲率半徑的變化，從而計(jì)算出多層膜內(nèi)應(yīng)力，硅基體的彈性模量為190 GPa，泊松比為0.2。采用型號(hào)為Nano Indenter G200的納米壓痕儀及連續(xù)剛度法測(cè)量薄膜的硬度，壓入深度約為50 nm。采用型號(hào)為WS?2005的涂層附著力劃痕儀[33]測(cè)定多層膜與基體間的結(jié)合力，加載速率100 N/min，最大載荷100 N，劃痕長(zhǎng)度4 mm，劃痕速度4 mm/min。采用型號(hào)為WTM?1E的球盤式摩擦試驗(yàn)機(jī)測(cè)試薄膜在大氣中(相對(duì)濕度約45%)的摩擦學(xué)性能，球試樣為直徑3 mm的GCr15鋼球(62HRC)，盤試樣為薄膜樣品，試驗(yàn)載荷0.5 N，相對(duì)滑動(dòng)速度0.105 m/s，測(cè)試時(shí)長(zhǎng)10 min。采用型號(hào)為Dektak3的臺(tái)階儀測(cè)量薄膜表面磨痕的截面輪廓并計(jì)算磨損體積，然后依據(jù)滑行距離、法向載荷和磨損體積計(jì)算出多層膜的磨損率。

2 結(jié)果與討論

2.1 薄膜的S、W摩爾比與結(jié)構(gòu)

眾所周知，磁控濺射制備的WS膜，其S、W摩爾比一般小于2，這是因?yàn)殡x子輻射、選擇性濺射、WS2靶材中S元素和W元素的濺射產(chǎn)額差異、高沉積溫度、低沉積氣壓等[34?35]諸多因素均能降低薄膜的(S)/(W)。圖1所示為能譜(EDS)分析法測(cè)得的薄膜(S)/(W)，可見純WS膜的(S)/(W)最高(為1.36)，而多層膜(樣品2~6)的(S)/(W)遠(yuǎn)低于純WS膜且隨著調(diào)制比的增大而增大。這說明DLC膜層在WS膜中的插入顯著降低WS膜的(S)/(W)，本文作者推測(cè)這可能是由于S元素與Si的親和力優(yōu)于DLC膜，而W元素則相反，從而導(dǎo)致DLC膜表面對(duì)W元素的吸附作用高于S元素，致使多層膜的(S)/(W)較低。另外，較厚的DLC膜層可有效抵擋高能粒子對(duì)WS層的轟擊，抑制S元素的揮發(fā)，繼而降低S元素?fù)p失，因而WS層的(S)/(W)隨DLC層膜厚的增加而增加。

圖1 薄膜的S、W摩爾比

由薄膜的XRD譜(見圖2)可知，純WS膜在2≈34°處出現(xiàn)了明顯的WS2(101)衍射峰，2≈14°處的WS2(002)衍射峰極其微弱，而多層膜均未出現(xiàn)與WS2相相關(guān)的衍射峰，這表明多層膜中的WS均為非晶(或微晶)結(jié)構(gòu)，即DLC層的插入顯著降低WS2相的結(jié)晶度。此外，所有多層膜和DLC膜中均未出現(xiàn)石墨和金剛石相的衍射峰，說明碳膜也以非晶或微晶的形式存在。DLC膜的拉曼光譜分析表明，其譜線由位于1331 cm?1的D峰和位于1530 cm?1的G峰疊加而成，其D/G(D峰與G峰的強(qiáng)度之比)為1.45。

圖2 薄膜的XRD譜

采用XPS技術(shù)對(duì)多層膜樣品2的價(jià)鍵結(jié)構(gòu)進(jìn)行分析。圖3所示為經(jīng)過30s氬離子刻蝕后樣品2的S2p和W4f XPS譜圖及擬合結(jié)果，多層膜中的S元素主要以WS2((162.0±0.1) eV、(163.2±0.1) eV)的形式存在(見圖3(a))，而W元素主要以WS2((32.6±0.1) eV、(34.8±0.1) eV)、WSO((33.8±0.2) eV、(35.9±0.2) eV)和WO3((35.7±0.2) eV、(37.9±0.2) eV)的形式存在(見圖3(b))，其中，WSO是WS2發(fā)生部分氧化的產(chǎn)物，WO3則是薄膜長(zhǎng)時(shí)間暴露大氣后的完全氧化產(chǎn)物?？梢?，多層膜中的W元素和S元素主要以WS2相的形式存在，無單質(zhì)W或單質(zhì)S。樣品2的C1s譜圖信噪比很低，這是因?yàn)镈LC膜厚度很小(約0.25 nm)，刻蝕之后已被完全清除，從而難以判斷膜中是否形成WC相。事實(shí)上，樣品2刻蝕前的C1s和W4f譜圖中未發(fā)現(xiàn)W—C鍵對(duì)應(yīng)的結(jié)合能峰(283.5和32.0 eV)，因而可以斷定多層膜中未形成WC相。

圖4(a1)~(a4)所示為薄膜的SEM像。從圖4(a1)中可知，純WS膜表面由“小顆?！睜钗镔|(zhì)聚集而成，“小顆?！钡某叽缂s10~50 nm，結(jié)構(gòu)較為疏松，這種結(jié)構(gòu)易在大氣中發(fā)生潮解氧化。而多層膜樣品表面與純DLC膜類似(見圖4(a2)~(a4))，致密而平整，表現(xiàn)為無特征膜形式。圖4(b1)~(b4)所示為薄膜橫截面的SEM像。從圖4(b1)中可以看到，純WS膜底部組織致密，上部呈疏松柱狀結(jié)構(gòu)生長(zhǎng)，與文獻(xiàn)[26]的結(jié)果一致。從圖4(b2)和(b3)中可以看到，多層膜與基體結(jié)合良好，結(jié)構(gòu)致密，表面比純WS膜光滑得多，調(diào)制比為3:20樣品的層狀幾何結(jié)構(gòu)明顯(見圖4(b3))?？梢?，多層結(jié)構(gòu)設(shè)計(jì)以及DLC層的引入，能夠有效抑制WS膜的柱狀生長(zhǎng)、降低表面粗糙度、提高薄膜致密度，從而有利于抑制其吸潮氧化。

圖3 多層膜樣品2表面各元素的結(jié)合能

2.2 薄膜的力學(xué)性能

圖5所示為薄膜硬度實(shí)測(cè)值和多層膜的理論混合硬度計(jì)算值。其中，DLC/WS多層膜的理論混合硬度采用下式計(jì)算[36]：

composite=(WSx/total)×WSx+(DLC/total)×DLC(1)

式中：WSx、DLC分別為單個(gè)多層周期中WS和DLC膜的厚度；WSx、DLC分別為WS和DLC單層膜的硬度，也即相同參數(shù)條件下制備的WS和DLC膜硬度值(1.2 GPa和19.8 GPa)，composite為納米多層膜的理論混合硬度。

圖4 薄膜的表面與橫截面的SEM像

圖5 薄膜硬度和多層膜的理論混合硬度

由圖5可知，多層膜的硬度隨著調(diào)制比的增大先降低后升高，并顯著高于其理論混合硬度值，這一方面說明多層膜的硬度服從復(fù)合材料混合法則，另一方面說明多層膜內(nèi)出現(xiàn)了明顯的多層界面強(qiáng)化效應(yīng)；小調(diào)制比多層膜內(nèi)的界面強(qiáng)化效應(yīng)十分強(qiáng)烈，比調(diào)制周期為50 nm的WS/a-C多層膜[37]中觀察到的要強(qiáng)烈得多。這是由于多層膜相鄰兩層材料的晶格常數(shù)不同，晶格常數(shù)較小的受到拉應(yīng)力，晶格常數(shù)較大的受到壓應(yīng)力，從而在多層膜的生長(zhǎng)方向上形成了交變應(yīng)力 場(chǎng)[38]，導(dǎo)致多層膜硬度升高。此外，硬質(zhì)相DLC與基質(zhì)WS2剪切應(yīng)力不同，位錯(cuò)運(yùn)動(dòng)需要更大能量，從而使多層膜硬度變大。再者，多層膜相鄰兩層的相不一樣，使材料生長(zhǎng)狀況交替改變，阻礙位錯(cuò)運(yùn)動(dòng)。

圖6所示為薄膜的內(nèi)應(yīng)力和結(jié)合力變化趨勢(shì)。從圖6(a)中可以發(fā)現(xiàn)，樣品5多層膜樣品呈現(xiàn)拉應(yīng)力，而其他多層膜樣品為壓應(yīng)力(用負(fù)值顯示)，幅值低于純WS膜和DLC膜且隨著調(diào)制比的增大而減小。研究表明，薄膜內(nèi)應(yīng)力主要源于薄膜生長(zhǎng)過程中的非平衡性、薄膜特有的微觀結(jié)構(gòu)以及不同材料的熱膨脹系數(shù)差異[39]。納米多層結(jié)構(gòu)以及DLC層的引入可以使薄膜形成復(fù)雜的界面結(jié)構(gòu)，抑制WS晶粒的柱狀生長(zhǎng)，從總體上改善界面間熱膨脹系數(shù)的差異和結(jié)構(gòu)錯(cuò)配度，從而降低內(nèi)應(yīng)力。另外，界面強(qiáng)化效應(yīng)增強(qiáng)，會(huì)阻礙位錯(cuò)的產(chǎn)生和增殖，進(jìn)而為內(nèi)應(yīng)力釋放提供更大的空間。從圖6(b)中可以發(fā)現(xiàn)，隨著調(diào)制比增大，薄膜結(jié)合力先增大后減小(4號(hào)多層膜例外)，這是由于少量的DLC就能阻斷WS膜層的柱狀生長(zhǎng)，使薄膜變得平整致密，從而提高結(jié)合力。隨著DLC層厚度進(jìn)一步增大，多層膜界面強(qiáng)化效應(yīng)減弱，層間滑動(dòng)阻力減小且更易于出現(xiàn)層間分離，致使結(jié)合力下降。至于多層膜5號(hào)樣品的內(nèi)應(yīng)力和4號(hào)樣品的結(jié)合力出現(xiàn)反常的具體原因，需要進(jìn)一步深入研究。

圖6 薄膜的內(nèi)應(yīng)力和結(jié)合力

2.3 薄膜的摩擦磨損性能

圖7所示為薄膜在大氣環(huán)境(相對(duì)濕度(RH)45%)中摩擦測(cè)試后的SEM像。從圖7中可以看出，純WS膜(見圖7(a))表面磨痕寬度較大，犁溝數(shù)量眾多，這與其硬度低、耐磨性能差等因素相關(guān)。樣品2(見圖7(b))的表面磨痕寬度較小，僅有少量磨屑粘附于磨斑兩邊，薄膜未被磨穿；樣品4(見圖7(c))磨損嚴(yán)重，膜層脫落嚴(yán)重，磨斑兩邊磨屑尺寸較大，Si基底大面積裸露，這與薄膜的結(jié)合力差，在摩擦過程中極易發(fā)生剝落結(jié)果相符；而純DLC膜(見圖7(d))表面基本完好，只有少量磨屑。

圖8(a)所示為薄膜在大氣環(huán)境中的平均摩擦因數(shù)。由圖8(a)可知，純WS膜的摩擦因數(shù)最低(0.138)，而多層膜的摩擦因數(shù)隨調(diào)制比的增大出現(xiàn)逐漸降低的趨勢(shì)。這是由于多層膜的摩擦因數(shù)不僅與薄膜的剪切強(qiáng)度有關(guān)，也與多層膜中潤(rùn)滑相WS2的含量和S/W比、致密度、表面粗糙度等因素有關(guān)。隨著調(diào)制比增大，多層膜的界面強(qiáng)化效應(yīng)逐漸減弱，薄膜的剪切強(qiáng)度下降，因而多層膜的剪切阻力降低，此外，WS層中S、W摩爾比增大也有利于降低摩擦因數(shù)。圖8(b)所示為薄膜在大氣環(huán)境中(相對(duì)濕度45%)的磨損率，多層膜的磨損率低于純WS膜，并且隨著調(diào)制比增加磨損率逐漸增大(樣品4的除外)，導(dǎo)致這一結(jié)果的原因與薄膜的結(jié)構(gòu)、硬度和結(jié)合力等因素相關(guān)。本文作者認(rèn)為，樣品2的結(jié)構(gòu)致密、硬度和結(jié)合力較高，因而磨損率較低，約為1.17×10?15 m3?N?1?m?1；而樣品4由于結(jié)合力低，容易從基體上剝落，加上硬度也較低，因此，樣品很快被磨穿，出現(xiàn)如圖7(c)所示的磨損形貌。

圖7 薄膜在大氣中(相對(duì)濕度45%)摩擦測(cè)試后的磨痕形貌

圖8 薄膜在大氣(相對(duì)濕度45%)環(huán)境中的摩擦因數(shù)和磨損率

3 結(jié)論

1) 多層結(jié)構(gòu)設(shè)計(jì)以及DLC層的引入可顯著降低WS膜層的S和W的摩爾比，有效抑制WS膜層的柱狀生長(zhǎng)，并誘導(dǎo)強(qiáng)烈的界面強(qiáng)化效應(yīng)，大幅度提高薄膜硬度，且WS膜層為非晶結(jié)構(gòu)。

2) 多層結(jié)構(gòu)有利于降低薄膜內(nèi)應(yīng)力，顯著提高薄膜的耐磨性能，而大氣環(huán)境中的摩擦因數(shù)高于純WS薄膜的。調(diào)制比為1:39的多層膜性能最優(yōu)，其硬度可達(dá)11.4 GPa，磨損率低至1.17×10?15 m3?N?1?m?1。

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Effect of modulation ratio on microstructure and mechanical properties of DLC/WSmultilayer films by magnetron sputtering

ZHENG Xiao-hua, LIN Ling-ling, CHANG Xin-xin, WANG Gong-qi, YANG Fang-er

(College of materials science and engineering, Zhejiang University of Technology, Hangzhou 310014, China)

The DLC/WSmultilayer films with various modulation ratios and modulation period of 10 nm were layer-by-layerdeposited on Si(100) substrates by magnetron sputtering method at 200 ℃. The effects of modulation ratio on the chemical composition, microstructure and interface of the films were characterized by means of scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffractometry (XRD) and X-ray photoelectron spectroscopy (XPS). The mechanical properties and tribological properties in atmosphere of the films were evaluated by residual stress tester, nano-indentation tester, scratch tester and ball-on-disc tribotester. The results show that DLC/WSmultilayers are compact and smooth, the strengthening of interfacial effect is remarkable and WSphase is defined as amorphous structure. As the modulation ratio increasing, the molar ratio of S and W increases from 0.77 to 1.08, the hardness decreases first and then increases while the compressive stress decreases in the film gradually, the adhesion to substrate increases first and then decreases, the friction coefficient decreases from 0.307 to 0.171, and the wear rate increases. Compared with pure WSfilm, DLC/WSmultilayer films have much better mechanical properties, and the film with modulation ratio of 1:39 has the best performance, its hardness is 11.4 GPa and its wear rate is of 1.17×10?15 m3?N?1?m?1.

WS2; diamond like carbon; multilayer; modulation ratio; microstructure; friction; wear

Project(LY15E010007) supported by Zhejiang Provincial Natural Science Foundation of China

2017-06-16;

2018-01-12

YANG Fang-er; Tel: +86-571-88320479; E-mail: yfe1230@163.com

10.19476/j.ysxb.1004.0609.2018.07.09

1004-0609(2018)-07-1343-08

TH117

A

浙江省自然科學(xué)基金資助項(xiàng)目(LY15E010007)

2017-06-16；

2018-01-12

楊芳兒，教授級(jí)高工；電話：0571-88320479；E-mail：yfe1230@163.com

(編輯 李艷紅)