發(fā)布時(shí)間：2018-06-20 02:39

  本文選題：高熵合金涂層 + 磁控濺射　； 參考：《四川理工學(xué)院》2015年碩士論文

【摘要】：材料表面合金化是金屬表面防腐的重要手段之一,隨著材料應(yīng)用的多樣化和使用環(huán)境的復(fù)雜化,對(duì)表面合金防腐層的性能要求也多重化。多數(shù)表面合金層難以同時(shí)滿足高硬度、高耐熱性、高耐腐蝕性、高耐磨抗性、抗氧化性等多重化性能的要求。高熵合金由五種及以上元素組成,各元素百分含量介于5at% 35at%,是一種新型合金體系。在高混合熵下,高熵合金表現(xiàn)出優(yōu)異的綜合性能,其中耐蝕性能甚至優(yōu)于304不銹鋼。將高熵合金引入到材料表面改性具有廣泛的應(yīng)用前景。本文采用等離子體五靶磁控濺射方法在X80基體上制得Al Ti Cr Ni Ta高熵合金耐蝕涂層。利用X射線衍射儀(XRD)、場(chǎng)發(fā)射掃描電鏡(FESEM)、原子力顯微鏡(AFM)、能譜儀(EDX)、附著力劃痕試驗(yàn)儀對(duì)涂層物相、微觀形貌、成分、附著力進(jìn)行表征。研究了濺射偏壓(0V,-100V,-120V,-160V)和濺射氣壓(0.2Pa,0.4Pa,0.6Pa,0.8Pa)對(duì)沉積速率、表面粗糙度、膜密度、涂層附著力的影響。利用電化學(xué)方法對(duì)不同工藝下(濺射偏壓、濺射氣壓、濺射功率、退火溫度)Al Ti Cr Ni Ta高熵合金涂層在0.5mol/L H2SO4溶液中的耐蝕性能進(jìn)行評(píng)價(jià)。并對(duì)涂層、X80基體在3.5wt%Na Cl溶液和0.5mol/L H2SO4溶液兩種腐蝕體系中的腐蝕行為進(jìn)行對(duì)比分析。研究發(fā)現(xiàn):在濺射氣壓0.4Pa,負(fù)偏壓為-100V下制得的Al Ti Cr Ni Ta高熵合金涂層,僅為單一的BCC結(jié)構(gòu),具有超細(xì)納米晶結(jié)構(gòu),此時(shí)涂層最致密,粗糙度最小,臨界載荷最大;電化學(xué)測(cè)試表明Al Ti Cr Ni Ta高熵合金可提高X80基體的耐Cl—腐蝕性能、致鈍化性能,在0.4Pa,負(fù)偏壓為-100V,0.5mol/L H2SO4溶液中涂層致鈍電流密度最大;自然腐蝕狀態(tài)下,Clˉ存在涂層腐蝕程度加劇;退火處理可釋放部分涂層內(nèi)應(yīng)力,提高涂層耐局部腐蝕性能。
[Abstract]:Surface alloying is one of the most important methods for anticorrosion of metal surface. With the diversification of material application and the complication of application environment, the performance requirements of surface alloy anticorrosive coating are also multiple. It is difficult for most surface alloy layers to meet the requirements of high hardness, high heat resistance, high corrosion resistance, high wear resistance, oxidation resistance and so on. The high entropy alloy is composed of five or more elements. The content of each element is between 5at% and 35ats. it is a new alloy system. The high entropy alloy exhibits excellent comprehensive properties under high mixing entropy, and the corrosion resistance of the alloy is even better than that of 304 stainless steel. The introduction of high entropy alloy to the surface modification of materials has a wide application prospect. In this paper, Al Ti Cr Ni Ta high entropy alloy corrosion resistant coatings were prepared by plasma five target magnetron sputtering on X80 substrate. The phase, microstructure, composition and adhesion of the coating were characterized by X-ray diffractometer, field emission scanning electron microscope (SEM), atomic force microscope (AFM), energy spectrometer (EDS) and scratch test. The effects of sputtering bias voltage (0V / 100V) and sputtering pressure on deposition rate, surface roughness, film density and coating adhesion were investigated. The corrosion resistance of Al Ti Cr Ni Ta high entropy alloy coating in 0.5 mol / L H _ 2SO _ 4 solution was evaluated by electrochemical method (sputtering bias voltage, sputtering pressure, sputtering power, annealing temperature and annealing temperature). The corrosion behavior of the coating X80 substrate in 3.5 wtNaCl solution and 0.5 mol / L H2SO4 solution was compared and analyzed. It is found that the Al Ti Cr Ni Ta high entropy alloy coating prepared at the sputtering pressure of 0.4 Pa and negative bias voltage of -100 V is a single BCC structure with ultrafine nanocrystalline structure. The coating is the densest, the least roughness and the most critical load. The electrochemical measurements showed that the high entropy Al Ti Cr Ni Ta alloy could improve the Cl-corrosion resistance and passivation performance of the X80 matrix. In 0.4 Pa, the negative bias voltage was -100 V + 0.5 mol / L H _ 2SO _ 4 solution, and the coating had the highest passivation current density in 0.5 mol / L H _ 2SO _ 4 solution. The corrosion degree of the coating is aggravated under natural corrosion condition, and annealing treatment can release part of the internal stress of the coating and improve the local corrosion resistance of the coating.
【學(xué)位授予單位】：四川理工學(xué)院
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TG174.4

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本文編號(hào)：2042561