Search results

1 – 4 of 4
To view the access options for this content please click here
Article
Publication date: 18 February 2019

Fen Peng, Wensheng Liu, Yufeng Huang, Siwei Tang, Chaoping Liang and Yunzhu Ma

The purpose of this study is to develop a monolayer surface coating of stearic acid on Sn-Ag-Cu solder powder to limit oxidation.

Abstract

Purpose

The purpose of this study is to develop a monolayer surface coating of stearic acid on Sn-Ag-Cu solder powder to limit oxidation.

Design/methodology/approach

Stearic acid was adsorbed onto Sn-Ag-Cu solder powder through liquid-phase adsorption. The isotherm of adsorption was measured and then the microstructure of coated powder was characterized by scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy.

Findings

The adsorption isotherm of stearic acid on the powder was “H” type, which revealed the layer-by-layer adsorption on non-porous surface. When the concentration of solution was in the range of 0.001-0.006 mol/L, with an adsorption amount of 0.12 ± 0.1 mg/g, monolayer stearic acid covered the solder powder completely. Uniform and integrated self-assembled monolayer coating was formed through hydrogen bonds between the oxygen ions in surface lattice of Sn3.0Ag0.5Cu solder powder and the —O—H hydroxyl group of stearic acid. The maximum angle of stability of coated powder also reduced by 2.87° compared with that of non-coated powder. The increase rate of oxygen content of coated powder was much slower than that of non-coated powder when they were exposed to humid air.

Originality/value

As a result, oxidation of fine solder powder was effectively limited. Essentially, this method can also be applied to the coating of other types of solder powder and has reference significance to other coating by liquid-phase method.

Details

Soldering & Surface Mount Technology, vol. 31 no. 1
Type: Research Article
ISSN: 0954-0911

Keywords

To view the access options for this content please click here
Article
Publication date: 18 February 2019

Fen Peng, Wensheng Liu, Yunzhu Ma, Chaoping Liang, Yufeng Huang and Siwei Tang

To explore substitutes for traditional Sn-Pb solder, Sn-20In-2.8Ag was considered because of its appropriate melting temperature, good reliability and high ductility at…

Abstract

Purpose

To explore substitutes for traditional Sn-Pb solder, Sn-20In-2.8Ag was considered because of its appropriate melting temperature, good reliability and high ductility at less than 100°C. However, the mechanical properties of Sn-20In-2.8Ag were not satisfactory. The reason for the poor mechanical properties of the Sn-20In-2.8Ag/Cu joint was revealed, and a way to solve the problem was found.

Design/methodology/approach

The microstructure evolution, characteristics of melting and solidification and joining performance with Cu were investigated using scanning electron microscopy (SEM), electron probe microanalysis, differential scanning calorimetry (DSC) and mechanical testing.

Findings

SEM results showed that the microstructure of Sn-20In-2.8Ag was composed of coarse dendritic Ag2In and γ phases, with Ag2In distributed at the grain boundaries. DSC measurements revealed that small amount of low temperature eutectic reaction, L → Ag2In + β + γ, occurred at 112.9°C. This reaction was caused by the segregation of indium, which is a process that has a strong driving force. In the lap-shear testing, a crack propagated along the grain boundary of the solder, and failure showed an intergranular fracture. This failure was connected with the three-phase eutectic and coarse Ag2In. Thus, to improve the mechanical properties, segregation of indium should be reduced and coarsening of Ag2In should be prevented.

Originality/value

The reason for the unsatisfactory mechanical properties of Sn-20In-2.8Ag was revealed via microstructural observations and solidification analysis, and the way to solve this problem was found.

Details

Soldering & Surface Mount Technology, vol. 31 no. 1
Type: Research Article
ISSN: 0954-0911

Keywords

To view the access options for this content please click here
Article
Publication date: 28 November 2019

Guangjin Chen, Peng Lu, Zeyan Lin and Na Song

This paper aims to introduce the history and major achievement of the Chinese private enterprise survey (CPES), which is one of the most enduring large-scale nationwide…

Abstract

Purpose

This paper aims to introduce the history and major achievement of the Chinese private enterprise survey (CPES), which is one of the most enduring large-scale nationwide sample surveys in China, providing important micro firm-level data for understanding and studying the development of Chinese enterprises and entrepreneurs over the past 26 years.

Design/methodology/approach

The main body of this paper is based on a bibliometric analysis of all literature using CPES until 2017.

Findings

This paper discusses problems that users may encounter during data mining. By doing so, it can assist other researchers to get a better understanding of what has been done (e.g. journals, topics, scholars and institutions) and do their research in a more targeted way.

Research limitations/implications

As members of the survey project team, the authors also take a prospect of the future data design and use, as well as offer some suggestions about how to use the CPES data to improve high-quality development and business environment evaluation in China.

Originality/value

This paper is the first to provide an overall picture of academic papers in China and abroad that have used the CPES data.

Details

Nankai Business Review International, vol. 10 no. 4
Type: Research Article
ISSN: 2040-8749

Keywords

To view the access options for this content please click here
Article
Publication date: 10 October 2016

Mingzheng Wu, Xiaoling Sun, Delin Zhang and Ci Wang

This study aimed to develop a moderated mediation model to explain the relationship between perceived organizational justice and the counterproductive work behavior (CWB…

Abstract

Purpose

This study aimed to develop a moderated mediation model to explain the relationship between perceived organizational justice and the counterproductive work behavior (CWB) of Chinese public servants. In this model, the authors assumed that job burnout mediates the relationship between perceived organizational justice and CWB and that moral identity moderates the relationship between job burnout and CWB.

Design/methodology/approach

A total of 210 public servants in China participated in this study, and their characteristics were measured by self-report tools. Hierarchical multiple regression analyses were used to test the moderated mediation model.

Findings

Analysis of the data demonstrated that perceived organizational justice, job burnout and moral identity influenced CWB. Moral identity moderated the relationship between job burnout and CWB, such that individuals with low moral identity are more likely to engage in CWB. Moreover, job burnout mediated the effect of perceived organizational justice on CWB, and the mediating effect of job burnout was moderated by moral identity. The indirect effect of perceived organizational justice on CWB through job burnout was significant among individuals with low moral identity but not among individuals with high moral identity.

Research limitations/implications

The findings highlight the self-regulatory function of moral identity in preventing CWB.

Practical implications

The study offers several significant suggestions to reduce CWB in Chinese public sector administration, such as by improving organizational justice perception, recruiting and selecting individuals with reference to their moral identity and monitoring employees’ job burnout regularly.

Originality/value

The authors developed and verified a moderated mediated model on the relationship between perceived organizational justice and CWB. The study revealed that job burnout has a mediating effect on the perceived organizational justice–CWB relation, providing important insights into the processes through which perceived organizational justice affects CWB.

Details

Journal of Chinese Human Resource Management, vol. 7 no. 2
Type: Research Article
ISSN: 2040-8005

Keywords

1 – 4 of 4