Melt Treatment-Porosity Formation Relationship in Al-Si Cast Alloys

The present study focuses on the porosity formation in three Al-Si cast alloys widely used in automotive industries viz. A319.0, A356.0, and A413.0 alloys under various conditions: stirring, degassing. Sr level, amount of grain refining, combined modification and grain refining, as well as hydrogen level. The solidification rate was the same for all alloys in terms of the mold used and its temperature. The microstructural investigations were carried out quantitatively using an optical microscope-image analyzer system scanning systematically over a polished sample area of 25 mm × 25 mm and qualitatively using an electron probe microanalzer equipped with EDS and WDS systems. The results were coupled with hardness measurements.

Fabrication and characterization of ZnO/Si Heterojunction by Laser Ablation for Solar Cell Application

Nanoparticles of semiconductor material have get more interest due to their desirable properties and applications in different areas. In this study Zinc Oxide Nanoparticles (ZnO NPs) were synthesized using laser ablation in water by applying (1600 pulses) of Nd- YAG laser ( λ = 1064 nm ) . The crystal structure morphology of synthesized ZnO NPs were investigated using X-Ray diffraction, atomic force microscope (AFM) , optical microscope image , and optical properties characterized using UV-VIS as well as FTIR spectroscopy . The investigation revealed high purity of the ZnO NPs thin film prepared with a regular and homogeneous semi-spherical shape nanoparticles distribution on the substrate surface with size around 50nm. The optical properties shows energy band gap (1.5 and 4) eV respectively. I-V characteristics have been studied for the heterojunction structure of (Ag/ZnO/Si/Al) indicates that this heterojunc-tion could be used as a solar cell with efficiency about 10.9%.

Effect of Cooling and Isothermal Aging on Microstructure Using Electroless Nickel (Boron) Plating

This paper presents a study on relationship of cooling rates towards the intermetallic compound (IMC) morphology. Cooling rate is an important parameter as it has significant effect towards the IMC microstructure formation that indirectly affects solders joint reliability. However, there is still insufficient study regarding the effect of cooling rate on the IMC thickness and microstructure behavior by using Nickel Boron as surface finish material in the electronic packaging industry. In this study, Sn-3Ag-0.5Cu solder was used on Nickel Boron as coating layer. Cooling rates were obtained by cooling specimens in different media which is water and air. The elemental composition was confirmed using Energy-dispersive X-ray spectroscopy and the microstructure of each IMC then analyzed using optical microscope, image analyzer and ImageJ. In this study, faster cooling rate (water) found to provide thicker IMC (6μm) compared to the other medium used. The morphology shape of each IMC also differs between different medium of cooling. IMC that undergoes faster cooling showed continues like layer while the one using air cooling formed scallop like IMC.

Study on Parameters Measurement System of Ball-End Cutter Based on Optical Vision Detection

In manufacturing field, the geometric parameters measurement of tool is an essential process in manufacturing ball-end cutter. An optical visual inspection system of ball-end cutter parameters was studied through designing CCD camera, optical microscope, image grabbing card, visual light and 3D detection tables. Through the grabbing and processing image information of ball-end cutter, visual inspection method was applied to measure parameters of ball-end cutter. Some algorithms including the gray scale processing, median filtering, edge detection and least square fitting method of measured data were analyzed to develop image processing and tool detection software of ball-end cutter. The reliability and accuracy of this detection system were verified through the practical test.

In-Situ Observations on Crack Propagation Along Polymer/Glass Interfaces.

The propagation of crack fronts along a PET-glass interface is illustrated. The experimental set-up consists of an Asymmetric Double Cantilever Beam in an optical microscope. Image processing techniques used to isolate the crack fronts are discussed in some detail. The fronts are found to propagate inhomogeneously in space and time, in forward bursts that spread laterally along the front for some distance. In some cases the forward movement of a crack can be almost entirely due to the lateral movement of forward steps (analogous to “kinks”) along the crack front.