The influence of substrate surface roughness on microstrip transmission line loss using conventional analyses and length-scale fractal analysis

2009 ◽  
Vol 42 (1) ◽  
pp. 21-35 ◽  
Author(s):  
Tracey Vincent ◽  
Brendan Powers ◽  
Isa Bar-On
Keyword(s):  
Surface Roughness ◽  
Transmission Line ◽  
Fractal Analysis ◽  
Substrate Surface ◽  
Length Scale ◽  
Microstrip Transmission Line ◽  
Substrate Surface Roughness ◽  
Line Loss ◽  
Influence Of Substrate

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.

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