Synthesis Of TiO2 Nanoparticles And Characterization Of Sn-3.0Ag-0.5Cu/TiO2 Via Nanoindentation And Selective Electrochemical Etching

Distributions of incorporated TiO2 nanoparticles in the Sn-3.0Ag-0.5Cu (SAC305) solder alloy were investigated by nanoindentation and selective electrochemical etching. Optimum size of the TiO2 reinforcement particles were obtained by the sol-gel centrifuge precipitation method. The SAC305-TiO2 composite solder was successfully blended by the aid of ball milling. Increment on the TiO2 weight percentage significantly refined the morphologies of the SAC305-TiO2 composite solder. Excessive TiO2 addition of 1.5 wt. % induced a reduction on the hardness value. The highest hardness performance was obtained for the SAC305-TiO2 composite solder with 1.0 wt. % of incorporated reinforcement particles. The hardness profiles indicate the dominant distribution of the TiO2 nanoparticles near the solder/substrate interfaces. The optimum SAC305-TiO2 composite solder attained slightly better electrochemical behavior with higher recorded current. Increment on the etching time mainly improved the observation on the shape profile and size refinement of the Cu6Sn5 and Ag3Sn IMC. Etching time up to 150 s deteriorates the morphologies of the IMC phase due to excessive removal of the Sn. Observation on the TiO2 nanoparticles were obtained by higher magnification on the micrographs with optimum etching time of 120 s. Clusters of the TiO2 nanoparticles were observed to cling onto the Cu6Sn5 IMC layer. Higher calculated mass and volume of the Sn removal were attained by the SAC305-TiO2 composite solder due to much favorable dissolution induced by the refinement on the morphologies

Microstructural Analysis of Sn-3.0Ag-0.5Cu-TiO2 composite solder alloy after selective electrochemical etching

This work aims to provide deep morphological observation on the incorporated TiO2 nanoparticles within the SAC305 by selective electrochemical etching. Cyclic voltammetry and chronoamperometry were used to investigate the selective etching performances. The removal of β-Sn matrix was conducted at a fixed potential of−350 mV. Average erformances of 2.19 and 2.30 mAwere attained from the chronoamperometry. The efficiency of β-Sn removal was pproved according to the reduction of the intensities on the phase analysis. Successful observation of the TiO2 near the Cu6Sn5 layer was attained for an optimum duration of 120 s. Clusters of TiO2 nanoparticles were entrapped by Cu6Sn5 and Ag3Sn intermetallic compound (IMC) layer network and at the solder/substrate interface. The presence of TiO2 nanoparticles at the solder interface suppresses the growth of the Cu6Sn5 IMC layer. The absence of a β-Sn matrix also allowed in-depth morphological observations to be made of the shape and size of the Cu6Sn5 and Ag3Sn. It was found that TiO2 content facilitates the β-Sn removal, which allows better observation of the IMC phases as well as the TiO2 reinforcement particles

A simple rectangular microstrip technique for determination of moisture content in Hevea rubber latex

A simple rectangular microstrip sensor for determination of moisture content in Hevea Rubber Latex is presented in this paper. The microstrip patch sensor was designed to operate at microwave frequency range from 1 to 5 GHz on a RT/Duroid substrate with 6.15 ±0.015 permittivity and 1.27 mm thickness. The width and length of the rectangular patch antenna was 18 mm and 38 mm, respectively. The reflection coefficient of the sensor loaded with Hevea latex at various percentages of moisture content from approximately 36.1% to 88.6 %. Calibration equations have been established between moisture content and phase of reflection coefficient at several selected frequencies. These equations were used to predict the amount of moisture content on Hevea latex based on the measured reflection coefficient values. The actual values of moisture content were obtained using standard oven drying method. The lowest mean relative error between actual and predicted moisture contents was 0.04 at 1 GHz

Recent Characterisation of Sol-Gel Synthesised TiO2 Nanoparticles

High demand and current applications have led to continuous study and subsequent improvement of TiO2 nanoparticles. The versatility of the sol-gel method allows employing different process parameters to influence the resultant properties of TiO2 nanoparticles. The evaluation and characterisation process of the synthesised TiO2 nanoparticles commonly involves a series of methods and techniques. Such characterisation methods include phase, structural, morphology and size analysis. A combination of data from these evaluations provides the relationship between the synthesis parameters and the end properties of TiO2 nanoparticles. Apart from the research findings on TiO2 nanoparticles, the characterisation used to obtain these findings is equally important. Thus, this chapter highlights the recent characterisation techniques and practices employed for TiO2 nanoparticles synthesised by the sol-gel method

Effect of TiO2 Nanoparticles on the Horizontal Hardness Properties of Sn-3.0Ag-0.5Cu-1.0TiO2 Composite Solder

The improvement in the hardness of Sn-3.0Ag-0.5Cu solder alloy reinforced with 1.0 wt. % TiO2 nanoparticles was evaluated by nanoindentation. A specific indentation array was performed on four different horizontal cross sections of the composite solder with different heights and diameters, in order to verify the mixing homogeneity of TiO2 nanoparticles within the Sn-3.0Ag-0.5Cu solder paste during the ball milling process. The phase analysis indicated successful blending of the Sn-3.0Ag-0.5Cu with the TiO2 nanoparticles. According the scanning electron microscopy micrographs, presence of the TiO2 nanoparticles reduced the size of the Cu6Sn5 and Ag3Sn intermetallic compound phases. Incorporation of the 1.0 wt. % TiO2 nanoparticles improved the hardness values up to 26.2 % than that of pure SAC305. The hardness values increased gradually from the top cross sections towards adjacent to the solder/substrate interface. The mechanism of the hardness improvement attained by the TiO2 nanoparticles addition were also investigated on the horizontal cross sections of the samples

Permittivity models for determination of moisture content in Hevea Rubber Latex

The commercial open-ended coaxial probe (Agilent 85070E) is the most commonly used sensor to determine the permittivity of wet materials. This paper extends the usability and applicability of the sensor to the estimation of moisture content in Hevea Rubber Latex. The dielectric constant and loss factor were measured using the commercial probe whilst the moisture contents were obtained using the standard oven drying method. Comparison results were obtained between the different dielectric models to predict moisture content in latex. Both the dielectric constant and the loss factor of rubber latex linearly increased with moisture content at all selected frequencies. Calibration equations were established to relate both the dielectric constant and the loss factor with moisture content. These equations were used to predict moisture content in Hevea latex from measured values of the dielectric constant and the loss factor. The lowest mean relative error between actual and predicted moisture contents was 0.02 at 1 GHz when using the Cole-Cole dielectric constant calibration equation

Selective etching and hardness properties of quenched SAC305 solder joints

Purpose – The purpose of this paper is to investigate the morphology of intermetallic (IMC) compounds and the mechanical properties of SAC305 solder alloy under different cooling conditions. Design/methodology/approach – SAC305 solder joints were prepared under different cooling conditions/rates. The performance of three different etching methods was investigated: simple chemical etching, deep etching based on the Jackson method and selective removal of b -Sn by a standard threeelectrode cell method. Phase and structural analyses were conducted by X-ray diffraction (XRD). The morphology of etched solder was examined by a field emission scanning electron microscope. The hardness evaluations of the solder joints were conducted by a Vickers microhardness tester. Findings – The Ag3Sn network was significantly refined by the ice-quenching process. Further, the thickness of the Cu6Sn5 layer decreased with an increase in the cooling rate. The finer Ag3Sn network and the thinner Cu6Sn5 IMC layer were the results of the reduced solidification time. The icequenched solder joints showed the highest hardness values because of the refinement of the Ag3Sn and Cu6Sn5 phases. Originality/value – The reduction in the XRD peak intensities showed the influence of the cooling condition on the formation of the different phases. The micrographs prepared by electrochemical etching revealed better observations regarding the shape and texture of the IMC phases than those prepared by the conventional etching method. The lower grain orientation sensitivity of the electrochemical etching method (unlike chemical etching) significantly improved the micrographs and enabled accurate observation of IMC phases

Corrosion characterization of Sn-Zn solder: a review

Yahaya, Muhamad Zamri/0000-0002-4750-4906; Mohd Nazeri, Muhammad Firdaus/0000-0003-4923-0184WOS: 000458380500006Purpose The purpose of this paper is to review and examine three of the most common corrosion characterization techniques specifically on Sn-Zn solders. The discussion will highlight the configurations and recent developments on each of the compiled characterization techniques of potentiodynamic polarization, potentiostatic polarization and electrochemical impedance spectroscopy (EIS). Design/methodology/approach The approach will incorporate a literature review of previous works related to the experimental setups and common parameters. Findings The potentiostatic polarization, potentiodynamic polarization and EIS were found to provide crucial and vital information on the corrosion properties of Sn-Zn solders. Accordingly, this solder relies heavily on the amount of Zn available because of the inability to produce the intermetallic compound in between the elements. Further, the excellent mechanical properties and low melting temperature of the Sn-Zn solder is undeniable, however, the limitations regarding corrosion resistance present opportunities in furthering research in this field to identify improvements. This is to ensure that the corrosion performance can be aligned with the outstanding mechanical properties. The review also identified and summarized the advantages, recent trends and important findings in this field. Originality/value The unique challenges and future research directions regarding corrosion measurement in Sn-Zn solders were shown to highlight the rarely discussed risks and problems in the reliability of lead-free soldering. Many prior reviews have been undertaken of the Sn-Zn system, but limited studies have investigated the corrosive properties. Therefore, this review focuses on the corrosive characterizations of the Sn-Zn alloy system