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用Al_2O_3/Tin双联沉积工艺改善铝合金在重载条件下的摩擦性能

作　者: Samir Hamid Awad Al-Rubyai
导　师: 钱翰城
学　校: 重庆大学
专　业: 材料加工工程
关键词: 铝合金微等离子体氧化陶瓷膜层
分类号: TG113.25
类　型: 博士论文
年　份: 2005年
下　载: 140次
引　用: 0次
阅　读: 论文下载

内容摘要

铝合金作为最重要的轻合金已广泛用于制造业,它具有一系列优越的物理、力学和工程性能:如比强度高,优良的导电及导热率,易于成形和加工,抗大气腐蚀能力强等优点。当然它亦表现出某些不足之处,例如其表面硬度较低,从而导致其耐磨性能较差,为改善其耐磨性,常采用表面沉积陶瓷膜层技术以提高其硬度,常用的气相沉积技术如物理气相沉积（PVD Physical vapour deposition）化学气相沉积（CVD Chemical vapour deposition）,物理化学气相沉积（PCVD Physical chemical vapour deposition）或物理辅助化学气相沉积（PACAD Plasma assisted chemical vapour deposition）以及离子增强化学气相沉积（PECVD Plasma enhanced chemical vapour deposition）。* 气相沉积法可在工件表面生成1-10μm的陶瓷膜如TiN,CrN、BN,WN 等,膜层硬而薄,致密光滑,摩擦系数低,适合于在低表面载荷情况下工作。另一种是液相沉积技术,如微等离子体氧化技术（MPO Microplasma oxidation）,此法是在特定成份电解液中通过微等离子体放电在工件表面沉积30-200μm（或更厚）的Al2O3 膜层,此膜层硬而厚,承载能力强,但较粗糙,摩擦系数高,适宜于在润滑条件下工作。本研究的目的是开发一种新的MPO/PVD 双联沉积工艺,在铝合金表面形成Al₂O₃/TiN 复合陶瓷层,此复合层既具有承载能力强的优点,又具有摩擦系数低,减磨、耐磨的特点。本研究对扩大铝合金的应用范围有理论意义和实用价值。本研究的创新点如下: ①提出了MPO/PVD 双联沉积工艺的设想,并成功地制备出了Al₂O₃/TiN 复合陶瓷层,该复合层承载能力高于单一沉积层,在干摩擦及润滑条件下服役均较理想。②研究了MPO 工艺沉积参数与膜层孔隙率的关系,同时提出了控制膜层孔隙率的方法,为获得优质Al₂O₃ 膜层提出了理论依据及具体方法。③研究了在MPO 工艺形成的Al₂O₃ 绝缘层上用PVD 工艺沉积TiN 层的技术并获得了结合良好的界面。本研究的其它重要工作还包括: ①探明了MPO 工艺电解液成份及操作参数与膜层厚度、硬度,生长速度等的关系,对膜层颗粒微观结构的影响,同时提出了获得高质量膜层的临界参数概念,为实现过程控制奠定了基础。

全文目录

Chinese abstract  5-7
English abstract  7-15
List of tables  15-17
List of figures  17-21
1 Introduction  21-33
  1.1 introductory remarks  21
  1.2 Tribological properties of aluminum alloys  21-24
  1.3 Main concept and inherent advantages of surface engineering  24
  1.4 Surface engineering of aluminum alloys  24-27
    1.4.1 Main task and early developments  24-25
    1.4.2 developments and main issues of present techniques  25-27
  1.5 Thesis objectives and outline  27-33
2 Literature review and overview of thesis research efforts  33-55
  2.1 Literature review  33-53
    2.1.1 Preface  33-34
    2.1.2 Single coating  34-39
    2.1.3 Simulation approaches  39-41
    2.1.4 Microplasma oxidation (MPO)  41-46
    2.1.5 Duplex coatings technologies  46-52
    2.1.6 Perspective of research in the literature  52-53
  2.2 Overview of thesis research efforts  53-55
3 Microplasma oxidation concept  55-69
  3.1 Dverview  55-56
  3.2 Fundamentals  56-62
    3.2.1 Phenomenology  56-57
    3.2.2 Theoretical models  57-60
    3.2.3 Discharge parameters  60
    3.2.4 Critical voltage  60-62
  3.3 Equipment  62-63
  3.4 Inherent advantages and Applications  63-66
  3.5 Summary  66-69
4 Vapour deposition and magnetron sputtering techniques  69-89
  4.1 Background  69
  4.2 General characteristics of PVD technique  69-72
  4.3 Common characteristics of PVD and CVD technique  72
  4.4 Classification of deposition techniques  72-75
  4.5 Classification of PVD techniques  75-77
  4.6 Magnetron and unbalanced magnetron sputtering  77-83
    4.6.1 Background  77
    4.6.2 Inherent advantages and benefits  77-78
    4.6.3 Basic and key technologies for development  78-83
  4.7 Importance of A1203/TiN coating in the thesis to PVD processes  83
  4.8 TiN coating  83-88
    4.8.1 Important properties and applications  83-85
    4.8.2 Plastic deformation and coating failure  85-86
    4.8.3 Widely researched duplex coatings combining TiN coating: benefits,issues and prospective future  86-88
  4.9 Summary  88-89
5 Optimization and Experimental Details  89-107
  5.1 Introduction  89
  5.2 Optimization of MPO electrolyte and deposition parameters  89-94
    5.2.1 Optimization of MPO electrolyte  89-93
    5.2.2 Optimization of deposition parameters  93-94
  5.3 Materials and specimens  94-95
  5.4 MPO equipment and setting  95-96
  5.5 Deposition of TiN coating  96-99
  5.6 Measurement of hardness and coating thickness  99
  5.7 Friction and wear tests  99-101
    5.7.1 Timken tester  99-100
    5.7.2 Pin-on disc test  100-101
  5.8 Scratch test  101-103
  5.9 SEM and XRD analysis  103
  5.10 Pores characterization  103-104
  5.11 Summary of the Experiments  104-107
6 Results and discussion  107-155
  6.1 Optimization of MPO electrolyte and deposition parameters  107-114
    6.1.1 Optimization of MPO electrolyte  107-110
    6.1.2 Optimization of deposition parameters  110-114
    6.1.3 MPO coating prepared using the optimized data  114
  6.2 MPO coating of different thickness  114-131
    6.2.1 Wear test results  114-119
    6.2.2 Micro structural observation and porosity characterization  119-125
    6.2.3 Hardness distribution  125-126
    6.2.4 Controlling porosity: study on research advances and selection of probable process  126-131
  6.3 Duplex coatings deposited using different TiN coating deposition parameters  131-140
    6.3.1 Effect of deposition condition on sample temperature  131-132
    6.3.2 XRD analysis  132-133
    6.3.3 SEM observation  133-135
    6.3.4 Mechanical properties  135
    6.3.5 Tribological properties  135-140
  6.4 Duplex coatings at different MPO coating thickness  140-153
    6.4.1 Mechanical properties  140-141
    6.4.2 Timken test  141-149
    6.4.3 Results from Pin-on-disc test  149-151
    6.4.4 Scratch test  151-153
  6.5 Summary of the Results  153-155
7 Conclusions and future work  155-159
  7.1 summary and findings  155-157
  7.2 future work  157-159
Acknowledgements  159-161
References  161-177
VITA  177-179
Appendices  179-197
  1. List of publication  179-191
  2. Chinese translation of the conclusions and summaries  191-197

用Al_2O_3/Tin双联沉积工艺改善铝合金在重载条件下的摩擦性能

内容摘要

全文目录

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