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The purpose of this paper is to explore the optimum average current density and pulse width for electrodeposition of gold in citrate electrolyte, and it is verified that the uniformity of film thickness can be effectively improved by periodic pulse reverse electroplating.

Apply forward pulse current, forward group pulse current and periodic pulse reverse current to the electrolyte and compare the film quality. High-frequency group pulses are used in both forward and reverse directions of the periodic pulse reverse current.

It is verified by experiments that periodic pulse reverse plating is superior to forward pulse plating and forward group pulse plating in terms of particle size, compactness, impurity content and thickness uniformity of the film. Add low-frequency vibration to the cathode under the same pulse electrical parameters as a comparative experiment to prove the beneficial effect of vibration on the allowable limiting current density and plating rate.

Gold film is often used as the sealing layer of precision parts. Increasing the thickness uniformity and improving the compactness of gold film will help to reduce the size error, improve the subsequent assembly accuracy and increase the service life of wear-resistant layer. Citrate gold plating electrolyte combines the advantages of cyanide electrolyte and cyanide-free electrolyte. Hence, this research focuses on the characteristics of periodic pulse reverse plating in terms of particle size, compactness, impurity content and thickness uniformity of the film and compare it with forward pulse plating and forward group pulse plating.

The purpose of this paper is to solve the issue of via filling and pattern plating simultaneously by concentration optimization of accelerator and leveler in the electroplating bath.

This paper designs a series of experiments to verify the performance of pattern plating with the via filling plating formula. Then the compositions of electroplating solution are optimized to achieve via filling and pattern plating simultaneously. Finally, the mechanism of co-plating for via and line is discussed in brief.

To achieve excellent performance for via filling and pattern plating simultaneously, proportion of additives are comprehensively considered in optimization of electroplating process. Effects of additives on the via filling and pattern plating should be taken into consideration, especially in achieving flat lines.

This paper discusses the different effects of accelerator and leveler on the via filling and the pattern plating, respectively. The process of co-plating for the via and the line is presented. The superfilling of via and the flat line are simultaneously obtained with the optimized via filling formula.

The purpose of this study is to investigate the two-dimensional unsteady inclined stagnation point flow and thermal transmission of Maxwell fluid on oscillating stretched/contracted plates. First, based on the momentum equation at infinity, pressure field is modified by solving first-order differential equation. Meanwhile, thermal relaxation characteristic of fluid is described by Cattaneo–Christov thermal diffusion model.

Highly coupled model equations are transformed into simpler partial differential equations (PDE) via appropriate dimensionless variables. The approximate analytical solutions of unsteady inclined stagnation point flow on oscillating stretched and contracted plates are acquired by homotopy analysis method for the first time, to the best of the authors’ knowledge.

Results indicate that because of tensile state of plate, streamline near stagnation point disperses to both sides with stagnation point as center, while in the case of shrinking plate, streamline near stagnation point is concentrated near stagnation point. The enhancement of velocity ratio parameter leads to increasing of pressure variation rate, which promotes flow of fluid. In tensile state, surface friction coefficient on both sides of stagnation point has opposite symbols; when the plate is in shrinkage state, there is reflux near the right side of the stagnation point. In addition, although the addition of unsteady parameters and thermal relaxation parameters reduce heat transfer efficiency of fluid, heat transfer of fluid near the plate can also be enhanced by considering thermal relaxation effect when plate shrinks.

First, approximate analytical solutions of unsteady inclined stagnation point flow on oscillating stretched and contracted plates are researched, respectively. Second, pressure field is further modified. Finally, based on this, thermal relaxation characteristic of fluid is described by Cattaneo–Christov thermal diffusion model.

This paper discusses how the grain size of plated copper changes as time passes by observing the copper surface topography after surface treatment with a roughening agent. This paper also discusses how the time until the recrystallization terminates depends on the amount and type of plating additives as well as current density. The results agree with the known mechanism of grain growth. As a result of our experiments, the best process to gain the optimal surface topography is proposed. We firmly believe that this paper will contribute to the improvement in quality control of the copper surface treatment process, which will in turn lead to the fabrication of PCBs and plastic packages with higher reliability.

The purpose of this paper is to present elastic buckling behaviour of simply supported and clamped thin rectangular isotropic plates having central circular cutouts subjected to uniaxial partial edge compression. Analysis is carried out for four different kinds of partial edge compression and it is extended to study the effect of aspect ratio of plate on buckling load.

A finite element method technique is used in the current work to solve the buckling problem of plate using eight node quadrilateral element and plate kinematics based on first order shear deformation theory. Results obtained from finite element analysis are first validated for isotropic square plates, without cutouts, subjected to uniaxial partial edge compression with some earlier published literature.

From the current work it is concluded that the buckling strength of square plates is highly influenced by partial edge compression, as compared to plate subjected to uniform edge compression; but with increase in aspect ratio, influence of partial edge compression on plate buckling load decreases.

This paper usefully shows how partial edge compression of plates affects the buckling strength of plate having circular cutouts. Generally, simply supported plates subjected uniaxial partial edge compression of Type I and Type III are found to be stronger than plates subjected to partial edge compression Type II and Type IV, respectively.

Electroless plating is an important process in printed circuit board and electronics manufacturing but typically requires temperatures of 70‐95°C to give a suitable deposition rate. This is becoming problematic in industry due to the rising price of energy and is a major contribution to production costs. Previous studies have noted beneficial effects of ultrasonic irradiation upon electroless plating processes and it has been reported that sonication can increase the plating rate and produce changes to the chemical and physical properties of the deposited coating. The purpose of this paper is to reduce the operating temperature of an electroless nickel bath by introducing ultrasound to the process.

The deposition rate of an electroless nickel solution was determined by two techniques. In the first method, test coupons were plated in an electroless nickel solution at temperatures ranging from 50‐90°C and the plating rate was calculated by weight gain. In the second approach the mixed potential (and hence the current density at the mixed potential) was determined by electrochemical analysis of the anodic and cathodic reactions. In both cases the plating rate was found with and without the application of an ultrasonic field (20 kHz). The electroless nickel deposits obtained in the plating tests were also analysed to determine the phosphorus content, microhardness and brightness.

The plating rates under ultrasonic agitation were always higher than under “silent” conditions. Most importantly, considering the objectives of this study, the deposition rate under sonication at 70°C was significantly higher than that found with mechanical agitation at 90°C. In addition, the results indicated that the deposits produced in an ultrasonic field had consistently lower phosphorus content, higher microhardness and were brighter than those prepared in an electroless nickel bath that was not sonicated.

Although previous work has been performed on the effect of ultrasound on electroless plating, all these studies have been carried out at the normal operating temperature of the electroless process. In this paper, ultrasound has been applied at temperatures well below those normally used in electroless nickel deposition to determine whether sonication can enable low temperature electroless plating.

A finite element formulation for flexure of isotropic plates based on a recent refined theory is developed. The refined theory incorporates effects of transverse shear, transverse normal stress and transverse normal strain. The Galerkin finite element method was used to develop the finite element equations for both plate bending and inplane problems. The performance of the proposed finite element model was evaluated by solving problems of uniformly loaded thick plates with different support conditions. The results of the present formulation are compared with Mindlin/Reissner and elasticity solutions.

An adaptive mesh refinement procedure is used in static plate bending finite element analysis to study the edge effects in Mindlin—Reissner plates.

A formulation has been developed for thermo‐elastoviscoplastic finite element analyses of continuous fibre‐reinforced composite plates subject to bending loading using a generalized continuum mechanics approach. Such an approach is used to model the non‐homogeneity in a composite, which is constituted by fibres embedded in a matrix material. The present formulation computes the respective stresses occurring in each constituent so that the respective yield criterion and flow rule of each constituent may be used if there is a material yielding in any constituent. Thermo‐elastic deformation of fibre and thermo‐elastoviscoplastic deformation of matrix are considered in the present study because the yield strength of fibre is substantially higher than that of matrix in many cases. Both constituents are assumed to be isotropic so that the von‐Mises yield criterion may be used for viscoplastic yielding of matrix. As numerical examples, a parametric study is performed for thermo‐elastoviscoplastic deformations of laminated composite plates subject to thermal bending loads.

Fibre‐reinforced plastic (FRP) materials have been recognised as new innovative materials for concrete rehabilitation and retrofit. Since concrete is poor in tension, a beam without any form of reinforcement will fail when subjected to a relatively small tensile load. Therefore, the bonding of FRP plate to reinforced concrete (RC) structure is an effective solution to increase its overall strength. In such plated beams, tensile forces develop in the bonded plate and these have to be transferred to the original beam via interfacial shear and normal stresses. Consequently, the debonding of FRP plates bonded to reinforced concrete beams is believed to be initiated by the stress concentration in the adhesive layer. Accurate predictions of the interfacial stresses are prerequisite for designing against debonding failures. In the present analysis, a simple theoretical model to estimate shear and normal stresses is proposed, including the variation in FRP plate fibre orientation. The solution shows significant shear and normal stresses concentration at the plates end. A parametrical study is carried out to show the effects of some design variables, e.g., thickness of adhesive layer and FRP plate, and the distance from support to cut ‐ off end of bonded plates.