Study of IMC at interfaces of Sn3.0Ag0.5Cu3.0Bi0.05Cr/Cu joints during thermal ageing

2014 ◽  
Vol 26 (4) ◽  
pp. 173-179 ◽  
Author(s):  
Guokui Ju ◽  
Fei Lin ◽  
Wenzhen Bi ◽  
Yongjiu Han ◽  
Wang Junjie ◽  
...  
Keyword(s):  
Cross Sections ◽  
Design Methodology ◽  
Ageing Time ◽  
Solder Matrix ◽  
Thermal Ageing ◽  
Service Reliability ◽  
Content Type ◽  
Isothermal Ageing ◽  
Interfacial Intermetallic Compounds ◽  
Scanning Electron

Purpose – The purpose of this study was to comparatively investigate interfacial intermetallic compounds (IMCs) in the Sn3.0Ag0.5Cu3.0Bi0.05Cr/Cu (SACBC/Cu) and Sn3.0Ag0.5Cu/Cu (SAC/Cu) solder joints, and to determine any differences. Design/methodology/approach – The samples were annealed after isothermal ageing at 150°C for 0, 168 and 500 hours, and their cross-sections were observed by scanning electron microscopy and energy dispersive spectroscopy. Findings – The interfacial IMC morphology in two joints had significant differences. For the Cu/SAC/Cu joints, the granular and short rod-like Ag3Sn particles attached on the surface and boundary of interfacial Cu6Sn5 grains were detected, and they coarsened observably with ageing time at 150°C, and lastly embedded at the grain boundaries. However, for the Cu/SACBC/Cu joints, there were tiny filamentous Ag3Sn growing on the surface of interfacial Cu6Sn5 grains, and the Ag3Sn had a tendency to break into nanoparticles, which would be distributed evenly and cover the IMC layer, profiting from the Bi and Cr precipitates from solder matrix during ageing. Originality/value – The paper implies that the addition of Bi and Cr could affect the IMCs of joints, thereby delaying interfacial reactions between Sn and Cu atoms and improving the service reliability. The SACBC solder is a potential alloy for electronic packaging production.

Corrosion inhibition of N80 steel in 10% HCl + 8% HBF4solution

2019 ◽  
Vol 66 (1) ◽  
pp. 1-10
Author(s):  
Juan Du ◽  
Yuning He ◽  
Pingli Liu ◽  
Yigang Liu ◽  
Xianghai Meng ◽  
...  
Keyword(s):  
Corrosion Inhibition ◽  
Design Methodology ◽  
X Ray Diffraction ◽  
Corrosion Morphology ◽  
Content Type ◽  
X Ray ◽  
N80 Steel ◽  
Corrosion Reaction ◽  
Hydrolysis Of ◽  
Scanning Electron

PurposeThis paper aims to analyze the corrosion and corrosion inhibition of N80 in 10 per cent HCl + 8 per cent fluoroboric acid (HBF4) solution for acidizing operation.Design/methodology/approachThe corrosion rate, kinetic parameters (Ea, A) and thermodynamic parameters (ΔH, ΔS) of N80 steel in fresh acid and spent acid, 10 per cent HCl + 8 per cent HBF4, 10 per cent HCl and 8 per cent HBF4solutions were calculated through immersion tests. The corrosion and inhibition properties were studied through X-ray diffraction and electrochemical measurements. The corrosion morphology of the corrosion product was examined by scanning electron microscopy (SEM).FindingsThe results demonstrated that the spent acid was the main cause of acidification corrosion, and the HBF4would cause serious corrosion to N80 steel. The results showed that the N80 steel was more seriously corroded in the spent acid than in fresh acid, and the hydrolysis of HBF4accelerates the dissolution process of N80 steel anode to control the corrosion reaction. The results showed that the acidification will definitely cause serious corrosion to the oil tube; therefore, necessary anti-corrosion measures must be taken in the acidification process.Originality/valueThe results showed that acidizing the formation with 10 per cent HCl + 8 per cent HBF4will definitely cause serious corrosion to the oil tube, especially when the spent acid flows back. Therefore, necessary anti-corrosion measures must be taken in the acidification process, especially in the spent acid flowback stage.

Design criteria for insulation materials applied in timber frame assemblies

2018 ◽  
Vol 9 (3) ◽  
pp. 252-263 ◽  
Author(s):  
Mattia Tiso ◽  
Alar Just
Keyword(s):  
Cross Sections ◽  
Fire Resistance ◽  
Design Methodology ◽  
Research Study ◽  
Design Model ◽  
Insulation Material ◽  
Content Type ◽  
Insulation Materials ◽  
Timber Frame ◽  
Improved Design

Purpose Insulation materials’ contribution to the fire resistance of timber frame assemblies may vary considerably. At present, Eurocode 5 provides a model for fire design of the load-bearing function of timber frame assemblies with cavities completely filled with stone wool. Very little is known about the fire protection provided by other insulation materials. An improved design model which has the potential to consider the contribution of any insulation material has been introduced by the authors. This paper aims to analyze the parameters that describe in a universal way the protection against the charring given by different insulations not included in Eurocode 5. Design/methodology/approach A series of model-scale furnace tests of floor specimens for three different insulation materials were carried out. An analysis on the charring depth of the residual cross-sections was conducted by means of a resistograph device. Findings The study explains the criteria and procedure followed to derive the coefficients for the improved design model for three insulations involved in the study. Originality/value This research study involves a large experimental work which forms the basis of the proposed design model. This study presents an important step for fire resistance calculations of timber frame assemblies.

Polysilicon nanogap structure development using size expansion technique

2011 ◽  
Vol 28 (3) ◽  
pp. 24-30 ◽  
Author(s):  
Uda Hashim ◽  
Nazwa Taib ◽  
Thikra S. Dhahi ◽  
Azizullah Saifullah
Keyword(s):  
Design Methodology ◽  
Electrical Characterization ◽  
Active Surface ◽  
Device Fabrication ◽  
Electrical Behavior ◽  
Structure Development ◽  
Content Type ◽  
Expansion Technique ◽  
Fabrication And Characterization ◽  
Scanning Electron

PurposeNanobiosensors based on nanogap capacitor are widely used for measuring dielectric properties of DNA, protein and biomolecule. The purpose of this paper is to report on the fabrication and characterization polysilicon nanogap patterning using novelties technique.Design/methodology/approachOverall, the polysilicon nanogap pattern was fabricated based on conventional lithographic techniques. For size expansion technique, by employing simple dry thermal oxidation, the couple of nanogap pattern has been expanded to lowest nanogap value. The progress of nanogap pattern expansion was verified by using scanning electron microscopy (SEM). Conductivity, resistivity, and capacitance test were performed to characterize and to measure electrical behavior of full device fabrication.FindingsSEM characterization emphasis on the expansion of polysilicon nanogap pattern increasing with respect to oxidation time. Electrical characterization shows that nanogap enhanced the sensitivity of the device at the value of nano ampere of current.Originality/valueThese simple least‐cost method does not require complicated nanolithography method of fabrication but still possible to serve as biomolecular junction. This approach can be applied extensively to different design of nanogap structure down to several nanometer levels of dimensions. A method of preparing a nanogap electrode according to the present innovation has an advantage of providing active surface that can be easily modified for immobilizations of biomolecules.

scholarly journals Selective laser melting of Ti6Al7Nb with hydroxyapatite addition

2014 ◽  
Vol 20 (4) ◽  
pp. 301-310 ◽  
Author(s):  
Teodora Marcu ◽  
Cinzia Menapace ◽  
Luca Girardini ◽  
Dan Leordean ◽  
Catalin Popa
Keyword(s):  
Selective Laser Melting ◽  
Laser Power ◽  
Design Methodology ◽  
Point Of View ◽  
Medical Applications ◽  
Laser Melting ◽  
Scanning Strategy ◽  
Content Type ◽  
Processing Times ◽  
Scanning Electron

Purpose – The purpose of this paper was to obtain by means of selective laser melting and then characterize biocomposites of medical-grade Ti6Al7Nb with hydroxyapatite (2 and 5 vol.%) and without hydroxyapatite, as reference. Design/methodology/approach – Rectangular samples were manufactured with the same scanning strategy; the laser power was between 50 W and 200 W. Processed samples were analysed by means of optical microscopy, scanning electron microscopy and microhardness. Findings – The results showed that despite the very short processing times, hydroxyapatite decomposed and interacted with the base Ti6Al7Nb material. The decomposition degree was found to depend on the applied laser power. From the porosity and bulk microstructure point of view, the most appropriate materials for the purposed medical applications were Ti6Al7Nb with hydroxyapatite processed with a laser power of 50 W. Originality/value – The originality of the present work consists in the study of the behaviour and interaction of hydroxyapatite additive with the Ti6Al7Nb base powder under selective laser melting conditions, as depending on the applied laser power.

The size effect on intermetallic microstructure evolution of critical solder joints for flip chip assemblies

2015 ◽  
Vol 27 (4) ◽  
pp. 178-184 ◽  
Author(s):  
Ye Tian ◽  
Justin Chow ◽  
Xi Liu ◽  
Suresh K. Sitaraman
Keyword(s):  
Solder Joint ◽  
Design Methodology ◽  
Growth Process ◽  
Flip Chip ◽  
Solder Bump ◽  
Solder Joints ◽  
Solder Matrix ◽  
Industrial Practice ◽  
Content Type ◽  
Flip Chips

Purpose – The purpose of this paper is to study the intermetallic compound (IMC) thickness, composition and morphology in 100-μm pitch and 200-μm pitch Sn–Ag–Cu (SAC305) flip-chip assemblies after bump reflow and assembly reflow. In particular, emphasis is placed on the effect of solder joint size on the interfacial IMCs between metal pads and solder matrix. Design/methodology/approach – This work uses 100-μm pitch and 200-μm pitch silicon flip chips with nickel (Ni) pads and stand-off height of approximately 45 and 90 μm, respectively, assembled on substrates with copper (Cu) pads. The IMCs evolution in solder joints was investigated during reflow by using 100- and 200-μm pitch flip-chip assemblies. Findings – After bump reflow, the joints size controls the IMC composition and dominant IMC type as well as IMC thickness and also influences the dominant IMC morphology. After assembly reflow, the cross-reaction of the pad metallurgies promotes the dominant IMC transformation and shape coarsened on the Ni pad interface for smaller joints and promotes a great number of new dominate IMC growth on the Ni pad interface in larger joints. On the Cu pad interface, many small voids formed in the IMC in larger joints, but were not observed in smaller joints, combined with the drawing of the IMC growth process. Originality/value – With continued advances in microelectronics, it is anticipated that next-generation microelectronic assemblies will require a reduction of the flip-chip solder bump pitch to 100 μm or less from the current industrial practice of 130 to150 μm. This work shows that as the packaging size reduced with the solder joint interconnection, the solder size becomes an important factor in the intermetallic composition as well as morphology and thickness after reflow.

Comparative analysis of stearates as grease lubricant thickeners

2019 ◽  
Vol 71 (9) ◽  
pp. 1093-1098
Author(s):  
Lidan Yao ◽  
Lixin Wang ◽  
Haining Yang ◽  
Chuan Li ◽  
Hui Song ◽  
...  
Keyword(s):  
Radial Distribution ◽  
Metal Ion ◽  
Design Methodology ◽  
Distribution Functions ◽  
Binding Energies ◽  
Radial Distribution Functions ◽  
Fiber Structure ◽  
Content Type ◽  
Dropping Point ◽  
Scanning Electron

Purpose This paper aims to investigate the influence of stearate types on the thickening ability, dropping point and fiber structure of greases. Design/methodology/approach Several greases were prepared from polyolefins and various stearates. The melting point of the stearates and the dropping point of the resultant greases were measured, and the intermolecular binding energies of the thickener and the radial distribution function of the metal–oxygen in the thickener were determined with the aid of molecular simulation. The microstructures of the greases were also analyzed via scanning electron microscopy. Findings A higher stearate binding energy was found to correlate to a higher dropping point of the resultant greases. The thickening ability of the stearate is related to the group and period of the constituent metal ion. Within a group, greater atomic numbers of the metal were correlated to lower thickening ability. In a period, as the atomic number of the metal increased, the thickening ability was enhanced. The radial distribution functions of metal and oxygen can explain the aggregation of the stearate thickeners in the grease. Originality/value This work compared the thickening capacity of several stearates. Guidelines for preparing stearates to tailor the resultant grease are presented.

Diffusion of elements during reflow ageing of Sn-Zn solder in liquid state on Ni/Cu substrate – theoretical and experimental study

2018 ◽  
Vol 30 (3) ◽  
pp. 137-144 ◽  
Author(s):  
Jagjiwan Mittal ◽  
Kwang-Lung Lin
Keyword(s):  
Diffusion Coefficients ◽  
Liquid State ◽  
Ageing Time ◽  
Solder Matrix ◽  
Content Type ◽  
Cu Substrate ◽  
State Diffusion ◽  
Cu Substrates ◽  
And Diffusion ◽  
Linear Increment

Purpose This paper aims to study the diffusion of Zn, Ni and Sn in the liquid state during the reflow ageing of the Sn-Zn solder above its melting point on an Ni/Cu substrate in relation to the formation of intermetallic compounds (IMCs). Design/methodology/approach The Sn-Zn solder is reflowed on Ni/Cu substrates and is aged at 503 K. The formation of IMCs and their composition is characterized using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). Diffusion coefficients and diffusion distances of Zn, Ni and Sn in the liquid state during reflow and ageing are theoretically calculated. Both experimental and theoretical behaviours for Ni and Zn diffusions are compared. Findings Calculations show a linear increment in the liquid-state diffusion coefficients of Ni, Zn and Sn in the solder matrix with a rise in temperature, but they remained constant during ageing. However, diffusion distances increased slowly with temperature but manifold with ageing time. The experimental results revealed segregation of Zn and Ni at the interface in the as-reflow aged specimens. The Zn was concentrated at the solder–substrate interface and it reacted with Ni diffusing from the substrate to form Ni-Sn-Zn IMCs. The rapid diffusion of Zn and Ni with the increase in ageing time increased their atomic concentrations in the IMCs against the reduction in Sn concentration owing to a comparatively slower diffusion. Originality/value The novelty of the paper is the detailed study of theoretical diffusion of Zn, Sn and Ni in the liquid state during reflow ageing of Sn-Zn above its melting points on a Ni/Cu substrate. This is compared with values obtained experimentally and related to the mechanisms of IMC formation.

Satisfaction of first-time residential clients with architectural services

2014 ◽  
Vol 12 (3) ◽  
pp. 316-335 ◽  
Author(s):  
Adedapo Adewunmi Oluwatayo ◽  
Eziyi Ibem ◽  
Dolapo Amole
Keyword(s):  
Design Methodology ◽  
Data Gathering ◽  
Service Reliability ◽  
Cross Sectional Survey ◽  
Cross Sectional ◽  
Content Type ◽  
Relationship Qualities ◽  
First Time ◽  
Practical Implications

Purpose – The aim of this study was to investigate the factors which define and predict the satisfaction of first-time residential clients of architects in Nigeria using Lagos as a case study. Design/methodology/approach – The study was based on the notion that satisfaction of first-time residential clients with architectural services is a combination of satisfaction with service, design and relationship qualities as well as reputation of the architect. A cross-sectional survey of randomly selected first-time residential clients of architects in the study area was conducted using pre-tested questionnaire as the principal data gathering instrument. Data were analyzed using descriptive statistics, factor and regression analyses. Findings – Of the seven factors identified, the factors which best define the satisfaction of the first-time residential clients were personalization of service, reliability of, confidence inspired by and personality of the architect. The best predictors of the satisfaction of the first-time residential clients of architects in Nigeria varied with the nature of service. However, it was observed that the experience of the architect cut across all service types as a significant predictor of client satisfaction. Research limitation/implication – Only residential clients were considered in the study. Other categories of clients may be considered in further studies. Practical implications – There is need for architects to consider the nature of services provided in their quest to satisfy their first-time residential clients. Originality/value – Previous studies have focused on experienced and mostly public sector clients. This study provides empirical data on the factors that influence the satisfaction of first-time private clients who engaged the services of architects for their personal homes.

Adhesive properties of S.S to PU and PVC leathers

2014 ◽  
Vol 26 (2) ◽  
pp. 108-117 ◽  
Author(s):  
Shouxiang Jiang ◽  
Dagang Miao ◽  
Diandong Zhao
Keyword(s):  
Electron Microscopy ◽  
Weight Loss ◽  
Bonding Strength ◽  
Design Methodology ◽  
Adhesive Properties ◽  
Content Type ◽  
Force Microscopy ◽  
Atomic Force ◽  
Scanning Electron ◽  
Better Than

Purpose – The purpose of this paper is to investigate the interfacial nanostructures and the adhesions of the stainless steel (S.S) coating to the polyurethane (PU) and polyvinyl chloride (PVC) leathers. Design/methodology/approach – PU leather and PVC leather deposit S.S nano-films on the surface of PU and PVC leathers in this study. The interfacial nanostructures were investigated by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The experimental results revealed that the surface roughness of the substrates had extremely important influence on the morphology of nano-films. The adhesions of the S.S coating to the PU and PVC leathers were investigated by the peel-off test. Findings – The results showed that the adhesive performance of the S.S nano-films coating on PVC leather was better than that on the substrate of PU leather. Moreover, a weight loss of per peeling force calculating formulation is proposed to determine the bonding strength between the S.S films and the substrates. Originality/value – In this paper, influence of different substrates on surface morphology of S.S coating was studied by SEM and AFM. Moreover, the weight loss of per peeling force calculating formulation was used to discuss the bonding strength between the S.S coating and the substrates. The research methods presented in this paper are of innovation significance to a certain extent.

Effect of P and Ge doping on microstructure of Sn-0.3Ag-0.7Cu/Ni-P solder joints

2016 ◽  
Vol 28 (4) ◽  
pp. 215-221 ◽  
Author(s):  
Xingchen Yan ◽  
Kexin Xu ◽  
Junjie Wang ◽  
Xicheng Wei ◽  
Wurong Wang
Keyword(s):  
Design Methodology ◽  
Solder Bump ◽  
Solder Joints ◽  
Diffusion Rate ◽  
Analysis Software ◽  
Content Type ◽  
Image Analysis Software ◽  
Interfacial Intermetallic Compound ◽  
Ge Doping ◽  
Scanning Electron

Purpose The purpose of this paper is to comparatively investigate the microstructure and interfacial intermetallic compound (IMC) layer of Cu/SACPG/Ni and Cu/SAC0307/Ni solder joints after thermal aging. Design/methodology/approach The specimens were thermally aged at 150°C for 0, 24, 168 and 500 h. The microstructure and morphology of the interface IMC layer were observed by means of scanning electron microscope. The IMCs and the solder bump surface were analyzed by EDS. Moreover, the thickness of IMC layer was measured by using the image analysis software. Findings The morphology of IMC of Cu/SAC0307/Ni solder joint was consistent with that of the Cu/SACPG/Ni joint, which indicates that the addition of P and Ge had little effect on the IMC formation. The needle-like (Cu,Ni)6Sn5 was formed at the interface of solder/Ni solder joints. Meanwhile, the tiny particles inferred as Ag3Sn phase attached to the surface of (Cu,Ni)6Sn5. The growth rate of IMC layer of the Cu/SACPG/Ni joint was smaller than that of Cu/SAC0307/Ni joint with aging time increasing, which means the addition of trace P and Ge can slightly suppress the diffusion rate of the interfacial IMC. Originality/value There are no previous studies on the formation mechanism of the IMC layer of SAC0307 solder alloys with P and Ge addition.

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