發(fā)布時間：2023-04-22 07:41

　　電子連接器的可靠性在很大程度上取決于表面涂層的抗腐蝕性能。為了降低表面金保護(hù)層的厚度,考慮提高擴(kuò)散阻擋層的耐腐蝕性能。鎳及其合金成本低、易于制備,并且在酸性條件下和含有氯離子的腐蝕介質(zhì)中具有優(yōu)異的耐腐蝕性。電沉積是合成具有可調(diào)節(jié)晶粒尺寸和結(jié)構(gòu)的納米晶鎳合金鍍層的方法。然而,納米晶鎳基材料的機(jī)械性能和腐蝕性能可能由于原子的擴(kuò)散和晶粒尺寸的粗化而下降。此外,當(dāng)晶粒尺寸小于30nm時,晶界的不穩(wěn)定性可能導(dǎo)致耐腐蝕性能下降。因此本課題研究在適當(dāng)溫度下對鎳鉬合金進(jìn)行退火處理從而穩(wěn)定晶界,通過直流電沉積制備納米晶鎳鉬合金涂層,并在高溫下進(jìn)一步退火。通過SEM,EDS,XRD和XRF分別表征了鎳鉬鍍層的表面形貌、化學(xué)組成、晶體結(jié)構(gòu)和厚度,并采用電化學(xué)測試來研究鍍層的抗腐蝕性能。主要結(jié)果如下:(a)通過改變鍍液的組成來調(diào)節(jié)鍍層中的鉬含量,結(jié)果表明沉積的鎳鉬鍍層的鉬含量對表面形態(tài)和腐蝕行為起主要影響。晶粒尺寸隨著鉬含量的增加而減小,但“顆�！背叽缭龃�。在這種情況下,隨著鉬含量增加,抗腐蝕性降低。此外,在1M硫酸中觀察到樣品的鈍化行為,而在3.5wt%氯化鈉中沒有發(fā)生明顯的鈍化。(b)研究了電流密度對耐腐...

【文章頁數(shù)】：75 頁

【學(xué)位級別】：碩士

【文章目錄】：
摘要
abstract
CHAPTER1 INTRODUCTION
    1.1 Research background
    1.2 Electrical connector
        1.2.1 Structure,function and materials of electrical connector
        1.2.2 Failures of Connectors
        1.2.3 Coatings for connector
    1.3 Surface functional materials for connectors
        1.3.1 Tin
        1.3.2 Nickel
        1.3.3 Ni-based alloys
    1.4 Research propose
CHAPTER2 EXPERIMENTAL METHODS AND CHARACTERIZATION DEVICES
    2.1 Materials and process for experiments
        2.1.1 Chemicals and materials for experiments
        2.1.2 Electrodeposition of Ni-Mo alloys
        2.1.3 Heat-treatment device
        2.1.4 Electrochemical characterization device
    2.2 Materials characterizations
        2.2.1 Field emission scanning electron microscope(FESEM)
        2.2.2 Energy dispersive X-ray spectroscopy(EDS)
        2.2.3 X-ray fluorescence thickness gauge(XRF)
        2.2.4 X-ray diffractometer(XRD)
    2.3 Electrochemical characterization
        2.3.1 Electrochemical Impedance Spectroscopy
        2.3.2 Polarization test
CHAPTER3 CORROSION RESISTANCE OF NI-MO ALLOY COATING WITH DIFFERENT MO CONTENT
    3.1 The preparation of Ni-Mo alloys
    3.2 Characterizations of as-deposited Ni-Mo coatings
    3.3 Anti-corrosion behavior of Ni-Mo coatings
        3.3.1 Anti-corrosion behavior of as-deposited Ni-Mo coatings in3.5wt%NaCl··
        3.3.2 Anti-corrosion behavior of as-deposited Ni-Mo coatings in1M H2SO
    3.4 Conclusion
CHAPTER4 EFFECT OF CURRENT DENSITY ON THE CORROSION BEHAVIOR OF NI-MO COATINGS
    4.1 The preparation of Ni-Mo alloys
    4.2 Characterizations of Ni-Mo coatings
    4.3 Electrochemical analysis of Ni-Mo coatings
    4.4 Conclusion
CHAPTER5 CORROSION BEHAVIOR OF AS-ANNEALED NI-MO COATINGS
    5.1 Thermal treatments
    5.2 Characterizations of as-annealed Ni-Mo coatings
    5.3 Anti-corrosion measurements of as-annealed Ni-Mo coatings
    5.4 Conclusion
CHAPTER6 SUMMARY
REFERENCES
致謝



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