Dissertation > Excellent graduate degree dissertation topics show

Research on Dip-Coating-Brazing between Ceramics and Aluminum

Author: WangBo
Tutor: NingXiaoShan
School: Tsinghua University
Course: Materials Science and Engineering
Keywords: Al2O3 AlN brazing hot dip coating transient liquid bonding
CLC: TG454
Type: Master's thesis
Year: 2011
Downloads: 23
Quote: 0
Read: Download Dissertation

Abstract


Ceramics have high-temperature strength, good corrosion resistance,high wear-resistance and high electrical isolation. Aluminum has uniqueproperties such as ductility, conductivity, resistance to corrosion, light weight,low permeability to H2and N2. Joining ceramics and aluminum is increasinglyimportant in the production of automobiles, electronic packaging and newceramic armor. However Al oxidized easily, the stable oxides formed on thesurface impede wetting and bonding ceramics to Al.In this paper, Al alloy films were formed on the surface of Al2O3andAlN ceramics by hot-dip aluminizing, and then the ceramics were brazed to Alby adopting conventional brazing methods. The Aluminizing bathcomposition was Al-Si and Al-Cu alloys. To improve the joining of AlNceramic and Al, Fe or Ti were deposited onto AlN ceramic by Magnetronsputtering.Hop-dip aluminizing method can improve wettability of ceramics by Alalloys. Under certain temperature and atmosphere conditions, Al-Si alloyfilms can be formed on Al2O3and AlN ceramics by hop-dip aluminizing andthen Al plates can be brazed tightly on the ceramics by using the films asbraze filler metal. The peel strength exceeds15N/mm. The best brazingtemperature for Al2O3and AlN are625℃to655℃and650℃to655℃,respectfully.During brazing process, Al-Si alloy films become liquid phase, and theliquid phase subsequently solidifies as a consequence of continued diffusionof Si into Al plates. At the end of process, the liquid phase completelysolidifies and a homogeneous metallurgical bond is produced. The bondingmechanism is similar to a transient liquid phase bonding.Increasing Si content in Al-Si alloy films can lower the brazingtemperature and decrease unbounded area. However Si has no direct effect ontear strength of joints. Increasing heating rate can reduce loss of Si and lower brazing temperature.Sputtering Fe on AlN ceramic is harmful for AlN and Al bonding.Sputtering Ti on AlN ceramic can reduce dip-coating temperature, but haslittle effect on brazing.

Related Dissertations

  1. Technology of Filling Clearance and Optimizing the Bonds during Ultrasonic Brazing,TG454
  2. Fabricationand Properties of SiC-AlN Multiphase Ceramics Prepared by Gelcasting,TQ174.62
  3. Preparation, Characterization and Catalytic Activity of Ni-Mn/γ-Al2O3 Catalyst for CO2 Methanation,O643.36
  4. Integrative Process of Vacuum Brazing and Heat-treating for YG6C Cemented Carbide and 5CrMnMo Steel,TG454
  5. Tribological Characterization of Uhmwpe Loaded with Alendronate Sodium in Ball-on-Disc Test,TQ325.12
  6. Prepatation of Pr/Al2O3 and Its Activity in Catalytic Ozonation,X703
  7. A Study on Highly Oriented AlN Thin Film Prepared by Pulsed Laser Deposition,O484.1
  8. Research on Phosphorus Oxychloride-Catalyzed Aniline N-Alkylation,O643.32
  9. Research of Properties and Preparation Technology of Multiphase Ceramic Coating with Reactive Flame Spraying Process on AZ31B,TG174.44
  10. Study on Preparation Technology and Properties of Al2O3-TiB2 Solid-state Reaction Multiphase Ceramic Coating on AZ31B Alloy,TG174.44
  11. Research on Deep Desulfurization and Regeneration Performance of the Adsorbents for Ultra-deep Reactive Adsorption Desulfurization of Diesel Fuel,TE624.5
  12. Preparation and Characterization of Al2O3/C Hybrid Aerogels and Al2O3 Aerogels,O648.17
  13. Compatibility Study of Interface between Na~+ Conductive Ceramic and Na,TQ174.1
  14. Application of Hierarchically Macro-/Mesoporous Structured Metal Oxides to Hydrodesulfurization of Thiophene and Benzothiophene,TQ032
  15. The Study of Plasma Spraying Al2O3 Insulating Coating on RAFM Steel and 316L Steel,TG174.444
  16. Preperation of Low Friction and Wear Resistant High-Purity Alumina Ceramic,TQ174.1
  17. Thermal Cycle Stability of SOFC Seal Material,TM911.4
  18. Degradation 2,4-DNP Using a Coupled Photocatalytic-BAF Process,X703
  19. Study on the Structure and Properties of Electrical Brush Planting Ni-P/Al2O3 Coating Aftering Heat Treatment,TQ153
  20. Preparation and Properties of Metal Toughened TiN/AIN Nano Multiayered Films Deposited by Magnetron Supptering,O484.1
  21. Synthesis of Dimethyl Oxalate by the Carbon Monoxide Coupling Reaction in Gas-phase,TQ225.242

CLC: > Industrial Technology > Metallurgy and Metal Craft > Welding, metal cutting and metal bonding > Welding process > Brazing
© 2012 www.DissertationTopic.Net  Mobile