Mechanical Stability of Passivation Films Deposited on Aluminium Substrates

1993 ◽  
Vol 309 ◽  
Author(s):  
P. Scafidi ◽  
M. Ignat ◽  
M. Dupeux
Keyword(s):  
Surface Roughness ◽  
Tensile Testing ◽  
Longitudinal Strain ◽  
Mechanical Stability ◽  
Substrate Surface ◽  
Crack Density ◽  
Testing Device ◽  
Substrate Surface Roughness ◽  
Scanning Electron

AbstractThe damage of films of two different passivation materials deposited on aluminium substrates was investigated. These systems were subjected to uniaxial stretch in an in situ tensile testing device adapted to a scanning electron microscope. Successive stages of crack development were observed: the failure is first in the film, then at the interface. The presence of a thermally grown aluminium oxide interlayer delays the decohesion process. The substrate surface roughness weakens the systems. The evolution of the crack density with the longitudinal strain was analysed and then fitted with a model based on a Weibull distribution function.

EFFECT OF SURFACE ROUGHNESS ON THE ADHESIVE AND TRIBOLOGICAL CHARACTERISTICS OF DLC COATING PREPARED ON Co-Cr-Mo ALLOY

2002 ◽  
Vol 16 (06n07) ◽  
pp. 952-957 ◽  
Author(s):  
D. Sheeja ◽  
B. K. Tay ◽  
H. M. Lam ◽  
S. K. Ng
Keyword(s):  
Surface Roughness ◽  
Life Span ◽  
Substrate Surface ◽  
Resistance Coefficient ◽  
Metal Alloy ◽  
Deposition Condition ◽  
Dlc Coatings ◽  
Dlc Coating ◽  
Short Life Span ◽  
Substrate Surface Roughness

The Co-Cr-Mo alloy is extensively used for tribological applications, including orthopaedic components in total joint replacements. High quality diamond-like carbon (DLC) coatings on metal/alloy substrates are of great interest as they are able to protect them from severe wear and thus prolong the life span of the component. Since the roughness of the metal/alloy varies depending on the applications, a study has been carried out to investigate the effect of substrate surface roughness on the microstructure, sliding life, wear-resistance, coefficient of friction, adhension and hardness of DLC coatings prepared on Co-Cr-Mo alloy substrates under the same deposition condition. The microstructure of the films studied using Raman spectroscopy suggests that the film prepared on a smoother surface contains slightly higher fraction of sp 3 bonded carbon atoms. The characterization using a pin-on-disk tribometer reveals that, the film prepared on the roughest sample (Ra ~ 0.06 μm) exhibits a very short life span of about 20 cycles compared to the film that is prepared on a relatively smoother surface (Ra ~ 0.02 μm), which exhibits a life span of about 340,000 cycles. In order to investigate the origin of this improved property of the DLC film on the smoother surface, adhesive strength and hardness of the films were studied by using a micro-scratch tester and a Nano-indenter, respectively. The results suggest that the film prepared on the smoother surface exhibits better adhesion (higher critical load) and relatively higher hardness.

Determination of Spread Activation Energy and Assessment of Wetting Behavior of Solders on Metallic Substrates

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
K. N. Prabhu ◽  
G. Kumar
Keyword(s):  
Surface Roughness ◽  
Operating Temperature ◽  
Substrate Surface ◽  
Substrate Material ◽  
Metallic Substrates ◽  
Wetting Behavior ◽  
Substrate Surface Roughness ◽  
Exponential Power ◽  
Kinetics Of

The effects of substrate material, substrate surface roughness, and operating temperature on the wetting behavior of Sn–37Pb, Sn–3.5Ag, and Sn–9Zn eutectic solders on metallic substrates were investigated. Solder spreading kinetics was successfully represented by the exponential power law (EPL): ϕ=exp(−Kτn). The EPL parameter K has the significance of accelerating the kinetics of relaxation while the parameter n represents the resistance to spreading process (spread resistance parameter). EPL parameters exhibited a decreasing trend with an increase in surface roughness. Estimated activation energies for solder spreading were found to be in between those reported for inert and highly reactive spreading systems.

Surface Properties and Cell Response of Bioactive Thermally Grown TiO2 Nanofibers

2014 ◽  
Vol 575 ◽  
pp. 219-222
Author(s):  
A.W. Tan ◽  
Belinda Pingguan-Murphy ◽  
Roslina Ahmad ◽  
Sheikh Akbar
Keyword(s):  
Surface Roughness ◽  
Articular Chondrocytes ◽  
Substrate Surface ◽  
Control Sample ◽  
Degree Of Crystallinity ◽  
Crystallographic Structure ◽  
Cartilage Growth ◽  
Bovine Articular Chondrocytes

Titania nanofiber (TiO2 NFs) arrays were fabricated in situ on a Ti-6Al-4V substrate by an oxidation process. Their surface morphology, crystallographic structure, surface roughness and wettability were characterized, as well as their in vitro interaction with bovine articular chondrocytes at different time points. Results showed that TiO2 NFs possessed greater surface roughness, hydrophilicity and degree of crystallinity. The in vitro cell studies revealed that TiO2 NFs substrate triggers enhanced cell adhesion, proliferation and extracellular matrix (ECM) formation compared to the untreated control sample. These results showed that chondrocytes have an affinity to the nanofibrous substrate surface and thus we suggest that such surfaces are suited to be used as an implant designed for cartilage growth.

Mechanical Characterization of Polymer Nanowires Using MEMS

2006 ◽  
Author(s):  
B. A. Samuel ◽  
Bo Yi ◽  
R. Rajagopalan ◽  
H. C. Foley ◽  
M. A. Haque
Keyword(s):  
Mechanical Properties ◽  
Tensile Testing ◽  
Furfuryl Alcohol ◽  
Mechanical Characterization ◽  
Uniaxial Tensile ◽  
Testing Device ◽  
Uniaxial Tensile Testing ◽  
Polymer Nanowires

We present results on the mechanical properties of single freestanding poly-furfuryl alcohol (PFA) nanowires (aspect ratio > 50, diameters 100–300 nm) from experiments conducted using a MEMS-based uniaxial tensile testing device in-situ inside the SEM. The specimens tested were pyrolyzed PFA nanowires (pyrolyzed at 800° C).

Stretchability enhancement of buckled polypyrrole electrodes for stretchable supercapacitors via engineering substrate surface roughness

2020 ◽  
Vol 343 ◽  
pp. 136099 ◽  
Author(s):  
Chen Zhao ◽  
Xiaoteng Jia ◽  
Kewei Shu ◽  
Changchun Yu ◽  
Yonggang Min ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Substrate Surface ◽  
Substrate Surface Roughness
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