Effect of Surface Morphologies on the Isothermal Oxidation Behavior of MCrAlY Coatings Fabricated by High-velocity Oxyfuel Processes

Focusing on improving the galvanizability of the third generation automotive steel, the effect of surface oxides morphologies on the galvanizability was studied. The results show that the surface oxide types of sample steels by XPS analysis after annealing in different conditions are the same, only MnO and Cr2O3 were detected and no complex oxides exist on the surface. Morphologies of surface oxides can greatly influence the galvanizability of the third generation automotive steel, nodule-like oxides surface can contribute to better wettability and inhibition layer than vitreous film-like oxides surface. Galvanizing panels of nodule-like oxides surface steels only show pinhole-sized bare spots, while panels galvanized from vitreous film-like oxide surface steels reveal larger areas of bare spots and uncoated areas. Inhibition layer observed in galvanizing panels of nodule-like oxides surface steels are compact but not homogeneous, some inhibition layer grains are fine, and others are coarse. While the inhibition layer grains of panels galvanized from vitreous film-like oxide surface steels have a non-compact morphology with some particularly fine equiaxed crystals which developed deficiently.

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Isothermal Oxidation Behavior of Ru Modified Aluminide Coating on a Fourth Generation Single Crystal Superalloy

Materials Science Forum ◽

10.4028/www.scientific.net/msf.512.111 ◽

2006 ◽

Vol 512 ◽

pp. 111-116 ◽

Cited By ~ 1

Author(s):

Yuki Matsuoka ◽

Kazuyoshi Chikugo ◽

Takakazu Suzuki ◽

Yasuo Matsunaga ◽

Shigeji Taniguchi

Keyword(s):

Phase Transformation ◽

Oxidation Behavior ◽

Coating Layer ◽

Aluminide Coating ◽

Isothermal Oxidation ◽

Fourth Generation ◽

Short Term ◽

Cross Sectional ◽

Local Oxidation ◽

Sectional Analysis

Ru coating prior to aluminizing is one of the effective methods to reduce the harmful intermediate layer that forms under the coating (SRZ) on a 4th generation Ni-base SC superalloy. This study examined the short-term isothermal oxidation behavior of this Ru-modified coating at 1373 K in air. Surface observation by SEM showed that the scale becomes flat and uniform in comparison to simple aluminide coating. XRD and cross-sectional analysis results also showed that phase transformation from β-NiAl to γ’-Ni3Al seldom occurs in the Ru-modified coating layer leading to the prevention of local oxidation.

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Mechanical Interlocking on Leadframe Surface for Bondability of Au Wedge Bond

Materials Science Forum ◽

10.4028/www.scientific.net/msf.857.79 ◽

2016 ◽

Vol 857 ◽

pp. 79-82

Author(s):

Roslina Ismail ◽

Fuaida Harun ◽

Azman Jalar ◽

Shahrum Abdullah

Keyword(s):

Optical Microscope ◽

Bonding Process ◽

Mechanical Interlocking ◽

Average Roughness ◽

Force Microscopy ◽

Atomic Force ◽

Surface Morphologies ◽

Scanning Electron ◽

Effect Of Surface

This work is a contribution towards the understanding of wire bond integrity and reliability in relation to their microstructural and mechanical properties in semiconductor packaging.The effect of surface roughness and hardness of leadframe on the bondability of Au wedge bond still requires detail analysis. Two type of leadframes namely leadframe A and leadframe B were chosen and scanning electron microscope (SEM) and optical microscope were used to inspect the surface morphology of leadframes and the quality of created Au wedge bond after wire bonding process. It was found that there were significant differences in the surface morphologies between these two leadframes. The atomic force microscopy (AFM) which was utilized to measure the average roughness, Ra of lead finger confirms that leadframe A has the highest Ra with value of 166.46 nm compared to that of leadframe B with value of 85.89 nm. While hardness value of different lead finger from the selected leadframe A and B obtained using Vicker microhardness tester are 180.9 VH and 154.2VH respectively.

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