Oxidation resistant effects of Ag2S in Sn–Ag–Al solder: A mechanism for higher electrical conductivity and less whisker growth

Park

Choi

et al. 2017

Sci Rep

Self Cite

Multi-walled carbon nanotube (MWCNT)/indium–tin–bismuth (In–Sn–Bi) composite nanostructures in which In–Sn–Bi nanoparticles have been penetrated by the MWCNT arrays were synthesized using a chemical reduction method. The incorporation of 0.6 wt% MWCNTs with high electrical conductivity into the In-based solder resulted in low minimum electrical resistivity (19.9 ± 1.0 µΩ·cm). Despite being reflowed at the relatively low temperature of 110 °C, the composite solder nanostructures were able to form mechanically stable solder bumps on a flexible polyethylene terephthalate (PET) substrate due to the MWCNT arrays with a high thermal conductivity of 3000 W/(m·K) and In–Sn–Bi nanoparticles with a low melting temperature of 98.2 °C. Notably, the composite solder bumps exhibited high flexibility (17.7% resistance increase over 1000 cycles of operation in a bending test) and strong adhesion strength (0.9 N average shear strength in a scratch test) on the plastic substrate because of the presence of mechanically flexible and strong MWCNTs dispersed within the solder matrix materials. These overall properties are due to the improved diffusivity of the composite solder nanostructures by the cover of the In–Sn–Bi nanoparticles along the MWCNT arrays and the network structure formation of the composite solder bumps.

Section: Resultsmentioning

confidence: 99%

Improved electrical and thermo-mechanical properties of a MWCNT/In–Sn–Bi composite solder reflowing on a flexible PET substrate

Park

Choi

et al. 2017

Sci Rep

Self Cite

“…An IN718 ingot was obtained from a supplier (SeAH Special Steel, Republic of Korea). The IN718 powders were fabricated using a gas atomizer (Hot Gas Atomization System, PSI Ltd., UK) 48 , 49 , 59 . For the gas atomization process, 2.0 kg of IN718 ingot was melted in a graphite crucible heated to 1600 °C for 30 min.…”

Section: Methodsmentioning

confidence: 99%

“…The amount of each element initially present in the IN718 powders was measured using inductively coupled plasma–atomic emission spectroscopy (ICP–AES, Optima 7300DV, PerkinElmer, USA). The concentration of oxygen and nitrogen in the IN718 (and in the BN nanosheets) was determined using an O/N analyzer (ON–900, Eltra GmbH, Germany) 48 , 49 , 59 . The density of the samples was measured using the Archimedes method.…”

Section: Methodsmentioning

confidence: 99%

Thermo-mechanical improvement of Inconel 718 using ex situ boron nitride-reinforced composites processed by laser powder bed fusion

Shin

et al. 2017

Sci Rep

Self Cite

Hexagonal boron nitride-reinforced Inconel 718 (h-BN/IN718) composites were fabricated using a laser powder bed fusion (LPBF) technique to treat a nanosheet-micropowder precursor mixture prepared in a mechanical blending process. Tailoring the BN in IN718 enhanced the thermal resistance of the composites, thereby dampening the sharpness of the melting temperature peak at 1364 °C. This is because the presence of the BN reinforcement, which has a low coefficient of thermal expansion (CTE), resulted in a heat-blocking effect within the matrix. Following this lead, we found that the BN (2.29 g/cm3) was uniformly distributed and strongly embedded in the IN718 (8.12 g/cm3), with the lowest alloy density value (7.03 g/cm3) being obtained after the addition of 12 vol% BN. Consequently, its specific hardness and compressive strength rose to 41.7 Hv0.5 ·cm3/g and 92.4 MPa·cm3/g, respectively, compared to the unreinforced IN718 alloy with 38.7 Hv0.5 ·cm3/g and 89.4 MPa·cm3/g, respectively. Most importantly, we discovered that the wear resistance of the composite improved compared to the unreinforced IN718, indicated by a decrease in the coefficient of friction (COF) from 0.43 to 0.31 at 2400 s. This is because the BN has an exfoliated surface and intrinsically high sliding and lubricating characteristics.

Advances in Materials Science and Engineering

“…is effect, however, is not observed for induction soldered joints. Recently, Rawat and Paul measured the electrical resistivities of Pt [33] and Kim et al measured the resistivity of the Sn-Ag-Al alloy by four-probe method [34].…”

Section: Characterization Of Solder Jointsmentioning

confidence: 99%

Properties of Sn‐Ag‐Cu Solder Joints Prepared by Induction Heating

Drienovský

Palcut

Priputen

et al. 2020

In the present work, one near-eutectic and three hypoeutectic Sn-Ag-Cu alloys have been employed for soldering by induction heating. The alloys were produced by induction melting of high purity Ag, Cu, and Sn lumps. The melting behavior of the alloys was investigated by differential scanning calorimetry. The solder alloys were subsequently applied for soldering by conventional hot-plate heating as well as induction heating and both soldering times and peak temperatures were recorded during soldering. Solder joints of two copper sheets were produced. The electrical resistance, tensile strength, and microstructure were analyzed on each soldered joint. The results indicate that the physical and mechanical properties of solder joints are determined by their chemical composition and soldering technology. Induction soldered joints not only have a slightly higher electrical resistivity but also higher mechanical strength, except of the 0.3 wt.% Ag hypoeutectic solder. The highest increase in ultimate tensile strength (28%) was observed for induction soldered joints with 1 wt.% Ag hypoeutectic solder. This effect is ascribed to the homogenous distribution of the intermetallic compounds within the eutectic in the alloy microstructure. The homogenous distribution is aided by rotation of liquid solder due to eddy currents and high-frequency magnetic field generated during induction heating.