Solid-state Interfacial Reaction Research Articles

Enhanced heat resistance of ABS/poly(N-(4-fluorophenyl) maleimide-alt-triallyl isocyanurate) composites based on solid-state interfacial reaction

The poor heat resistance of acrylonitrile-butadiene-styrene copolymer (ABS) is a significant limitation that restricts its application in various fields, including automotive, electronic devices and other fields. To address this issue, we employed a strategy involving the crosslinking of a macromolecular heat-resistant agent to enhance the heat resistance of ABS. Poly(N-(4-fluorophenyl) maleimide-alt-triallyl isocyanurate) (PFT), a reactive heat-resistant agent known for its rigid and reactive structures, was selected for this purpose. ABS/PFT composites were prepared by subjecting them to γ-ray irradiation, resulting in crosslinking through a solid-state interfacial reaction (SSIR) between PFT and ABS. The results show that the heat distortion temperature (HDT), glass transition temperature (Tg), tensile strength and bending strength of the irradiated ABS/PFT (i-ABS/PFT) composites increased by 23.86%, 23.35%, 20.0% and 9.0%, respectively compared to pure ABS. Furthermore, ABS/PFT composites with SSIR exhibit the highest heat resistance, Tg and HDT compared to non-SSIR ABS. The work presented in this paper provides a new direction for the heat-resistant modification of ABS and will expand its application in new fields.

Long-Term Aging Study on the Solid State Interfacial Reactions of In on Cu Substrate.

Indium is considered a candidate low-temperature solder because of its low melting temperature and excellent mechanical properties. However, the solid-state microstructure evolution of In with different substrates has rarely been studied due to the softness of In. To overcome this difficulty, cryogenic broad Ar+ beam ion polishing was used to produce an artifact-free Cu/In interface for observation. In this study, we accomplished phase identification and microstructure investigation at the Cu/In interface after long-term thermal aging. CuIn2 was observed to grow at the Cu/In interface and proved to be a stable phase in the Cu-In binary system. The peritectoid temperature of the Cu11In9 + In → CuIn2 reaction was confirmed to be between 100 and 120 °C. In addition, the growth rate of CuIn2 was discovered to be dominated by the curvature of the reactant Cu11In9/In phase and the temperature difference with the peritectoid temperature. Finally, a comprehensive microstructural evolution mechanism of the Cu/In solid-state interfacial reaction was proposed.

Room-temperature, rapid, solid-state solder bonding technology for future ultra-high-density interconnects manufacturing

Developing ultra-high-density interconnects using current technologies presents certain limitations. It is because traditional solder joint technology employs a liquid-solid interfacial reaction process that makes it difficult to control the shape of the solder joint, thus limiting the size, pitch, and density of interconnects. Although the Cu–Cu direct bonding technique can help fabricate high-density interconnects, its high cost and limited application in consumer electronics present further challenges. In this study, we developed a simple, rapid, and cost-efficient method for fabricating high-density interconnects. We produced homogeneous submicron solder particles as small as 300 nm through ultrasonic treatment. The homogeneous size distribution was achieved by minimizing inter-particle ripening reactions, sluggish diffusion, and low Gibbs-Thomson chemical potential in the medium-entropy Sn–Bi–In-based solder particles. We dispensed the particle solution between two Cu substrates, and they bonded within 5 min at room temperature through a solid-state interfacial reaction. The shear strength of the bonding is around 14.8 ± 1.2 MPa. Our bonding technology shows potential for use in 3D integration to manufacture ultra-high-density interconnects.

Effects of solid-state interfacial reaction on the mechanical properties of carbon nanotubes reinforced aluminum matrix composites with heterogeneous structure

To overcome strength-ductility trade-off in carbon nanotubes (CNTs) reinforced Al matrix composites, we developed a novel and controllable strategy via a combination of different length of CNTs and fine/coarse-grained matrices. Microstructure analysis showed that Al4C3 nanorods about 100 nm were distributed in the fine grain zone (FGZ), while CNTs of micron length were distributed in the coarse grain zone (CGZ). Different sizes of reinforcements play different strengthening roles, and the bimodal grains can effectively coordinate deformation, thereby achieving a good combination of strength and ductility. Heat treatment does not affect the microstructure of the FGZ, but significantly affect the CNT/Al interface bonding in the CGZ. Heat treatment at an appropriate temperature can further improve the strength of the composite by improving the interface bonding. When the heat treatment temperature is too high, the coarsening of Al4C3 in CGZ will deteriorate the mechanical properties of the composite.

Solid-state interfacial reaction of Sn-Ag solders with polycrystalline Cu and (0 0 1) Cu substrate

• For sn-Ag solder, the growth of Cu 3 Sn on (0 0 1)Cu is faster than on polycrystalline Cu in aging. • Ag increases the difference in Cu 3 Sn thickness on (0 0 1)Cu and polycrystalline Cu in aging. • Ag is beneficial to maintain the preferred orientation of Cu 6 Sn 5 in aging. The growth of Cu 3 Sn is associated with the formation of Kirkendall voids and is important to the reliability of solder joints. In this paper, the effect of Ag on the growth behavior of Cu 3 Sn on (0 0 1) Cu and polycrystalline Cu during aging was compared. Besides, the orientation evolution of Cu 6 Sn 5 on (0 0 1) Cu during aging was also investigated. Results suggested the growth rate of Cu 3 Sn on (0 0 1) Cu is higher than that of polycrystalline Cu during solid-state aging and the difference in the Cu 3 Sn layer thickness increases with the increases of Ag content in the solder. Moreover, the addition of Ag is beneficial to maintaining the preferred orientation of Cu 6 Sn 5 on (0 0 1) Cu during solid-state aging. The results have great help to deepen the understanding of the difference in growth behavior of intermetallic compounds on (0 0 1) Cu and polycrystalline Cu during aging.

Phase transformation of nonstoichiometric cubic tungsten carbide on the surface of carbon nanotubes during high-temperature annealing of aluminum matrix composites

In this work, metal matrix composites based on 5049 aluminum alloy reinforced with multi-walled carbon nanotubes (CNTs) coated with nonstoichiometric cubic tungsten carbide were obtained by powder metallurgy. For the first time for this system, high-temperature annealing of the synthesized composites at 500–600 °C for 0.5 h was carried out. Effect of the annealing on the evolution of the structural-phase composition and the change in the microhardness and Young's modulus of the bulk composite was studied. Characterization of the structure shows that despite the growth of the matrix grains, the structural heterogeneity inherent for composites in the as-synthesized state is retained after heat treatment. Along with coarse grains, fine grains still remain, which indicates an increased resistance to recrystallization of the composite even at a temperature of ∼0.9Tm. XRD analysis shows that annealing at temperatures above 525 °C leads to a solid-state interfacial reaction of the ceramic coating on the CNTs surface with the matrix material, resulting in the in-situ formation of the WAl12 intermetallic compound around the reinforcing particles and Al4C3 nanorods. At the same time, the structural integrity of the CNTs is preserved. An increase in the annealing temperature contributed to an increase in the intensity of phase transformations and an increase in the fraction of the in-situ phases. The microhardness and Young's modulus of the composites decreased by ∼20% and ∼27%, respectively. Nevertheless, despite the increase in the grain size, the level of these properties remained quite high and equal to 141 HV and 80 GPa, correspondingly, due to the formation of a larger fraction of the in-situ WAl12 and Al4C3 phases. The obtained results are applicable for varying the mechanical properties of the composite by controlling the degree of in-situ reaction between the matrix alloy and the ceramic coating on the CNTs.

Effects of Solid-State Interfacial Reaction on the Mechanical Properties of Carbon Nanotubes Reinforced Aluminum Matrix Composites with Heterogeneous Structure

Effects of Solid-State Interfacial Reaction on the Mechanical Properties of Carbon Nanotubes Reinforced Aluminum Matrix Composites with Heterogeneous Structure

Effects of W contents on the solid-state interfacial reactions of Sn/Co-W

Effects of W contents on the solid-state interfacial reactions of Sn/Co-W

Alcohol-thermal synthesis of approximately core-shell structured Al@CuO nanothermite with improved heat-release and combustion characteristics

Metastable intermolecular composites (MICs), also called nanothermites, are attracting wide attention mainly due to the increased interfacial contact area of the fuels and oxidants therein. In this study, an alcohol-thermal technique is adopted to synthesize approximately core-shell structured Al@CuO MICs, in which process copper acetate is used as the precursor of CuO while Al powder with a wide size distribution (50 nm−5 µm in diameter) is used as cores. The energy-release characteristics of the materials are studied by performing thermal analysis, constant-volume combustion cell tests, and high-speed camera imaging of the combustion process. The results show that Al nanoparticles are surrounded by CuO nanoparticles that are with an average diameter of about 10 nm, while micron-sized Al particles are coated by a continuous layer of nanoplatelets that are assembled from CuO nanoparticles. Benefiting from the enhanced interfacial contact compared with that of ultrasonically mixed counterpart, Al@CuO shows a lower apparent activation energy of solid-state interfacial reaction, a higher light intensity, a shorter burning time, a larger pressure output, and a higher pressurization rate. It is also found that equivalent ratio has a great effect on the combustion process, and a slightly fuel-rich formulation is preferred in this study. The synthesis method developed in this study may also be adapted to the preparation of other core-shell structured MICs.

Kinetics of Ag <sub>3</sub>Sn and Ag <sub>4</sub>Sn Growth between Sn and Ag During Solid-State and Liquid-State Interfacial Reactions

Kinetics of Ag <sub>3</sub>Sn and Ag <sub>4</sub>Sn Growth between Sn and Ag During Solid-State and Liquid-State Interfacial Reactions

Enhanced thermal property and anti-moisture absorption of PA6/P (N-(4-carboxyphenyl)maleimide-alt-triallyl isocyanurate) composites based on solid-state interfacial reaction

In order to expand its application range in electronics and membrane industries, this paper aimed to develop polyamide 6 (PA6)/P (N-(4-carboxyphenyl) maleimide-alt-triallyl isocyanurate) (PCT) composites with heat-resisting, thermally conductive and anti-moisture, by employing PCT as a reactive reinforcement material and applying irradiation for solid-state interfacial reaction (SSIR) between PCT and PA6. According to the results, the SSIR occurred between PA6 and PCT. Compared with non-SSIR PA6, the PA6/PCT composite with SSIR showed the highest heat resistance, thermal conductivity and anti-moisture absorption and its relative crystallinity (Xc), glass transition temperature (Tg), and heat deflection temperature (HDT), thermal conductivity and anti-moisture absorption were improved by 61.4, 24.0, 83.9, 18.5 and 40.2%, respectively. This is because that the chemical bond between the PCT surface and the PA6 matrix is formed by SSIR, which provides a theoretical basis either for the development of PA6 or other semi-crystalline polymers.

Improving the mechanical properties of B4C/Al composites by solid-state interfacial reaction

The effect of solid-state interfacial reaction between B4C and Al was often overlooked in related research. In the present study, B4C/Al composites were successfully produced by hot pressing sintering. Nanoscale interfacial reaction product, aluminum boron carbide (Al3BC), was formed in B4C/Al composites even at a low sintering temperature (570 °C). The distribution and properties of the nanoscale Al3BC were characterized by transmission electron microscopy (TEM). The results indicate that the interfacial product Al3BC can disperse into the Al matrix during hot rolling. The Al3BC nanoparticles located in the Al matrix lead to a significant strength improvement, around 65 MPa through the geometrically necessary dislocations (GNDs) strengthening and Orowan strengthening in B4C/Al composites with 30% weight percent of B4C. The contributions of Al3BC formation on strength and strengthening mechanism are discussed in detail.

Solid state interfacial reactions in a ceria-coated Ni-based superalloy

Perovskite type phases are known to improve the adherence of protective oxide scales grown onto chromia- and alumina-forming alloys and coatings. The present study investigates the interfacial reactions occurring during the high temperature oxidation of a ceria coated Ni-based superalloy at 1100 °C. The substrate firstly grew a duplex oxide scale with a NiAl2O4 spinel on top of an α-Al2O3 scale underneath the ceria coating. Increasing oxidation time led to the development of Al-rich and Ce-rich nanometric grains at the oxide scale/coating interface and to the progressive vanishing of the NiAl2O4 spinel. Micro-Raman analyses demonstrated the formation of cerium aluminate CeAlO3 by solid-state reaction between Al2O3 and CeO2 favoured by an Al supply coming from the substrate. The results are in line with the thermodynamic calculations.

A Novel Resistance Measurement Methodology for $In~Situ$ UBM/Solder Interfacial Reaction Monitoring

This article presents a methodology to investigate, in situ , the interfacial solid-state reaction of alternative metallurgical systems, such as Cu/Ni/Sn and Ni/Cu/Sn bumps. The methodology is based on continuous in situ resistance measurements as a function of time and temperature. It allows to extract solid-state interfacial kinetic reaction parameters, such as activation energy and power factor, in a much more precise and faster way than the conventionally used methods. Moreover, the continuous recording of resistance change makes comparing different metallurgical systems easier. This article shows the results obtained using this method for Cu/Ni/Sn and Ni/Cu/Sn.

Minor P Doping to Effectively Suppress IMC Growth in Solder Joints with Electroplated Co(P) Metallization

Electrodeposited Co(P) layers with three different P contents (0.5 wt.%, 0.8 wt.%, and 2 wt.%) have been coated on Cu substrates by adding minor amounts of sodium hypophosphite to the Co plating bath. These hcp-Co(P) coatings exhibited highly preferred (002) orientation. Solid-state interfacial reactions of 6-μm-thick Co(P)/Cu with pure Sn were conducted at temperatures of 160°C to 210°C. In the Sn/Co-0.5 wt.%P/Cu reactions, a uniform intermetallic compound (IMC) layer of CoSn3 was formed and its thickness increased linearly with aging time. Most importantly, the IMC growth was significantly inhibited compared with that of the Sn/Co/Cu reaction without P doping. When the P content was increased to 0.8 wt.%, the formed phases contained not only CoSn3 but also metastable CoSn4, and the suppression effect became stronger. The IMC growth rate at 180°C was decreased by 95% in comparison with the pure Co case. The growth rate with Co-2 wt.%P was between that observed for the 0.5 wt.% and 0.8 wt.% P compositions, so the IMC growth kinetics of the Co coatings with 0.5 wt.% and 0.8 wt.% P compositions were systematically investigated. Minor P doping in the Co deposit greatly suppressed the IMC growth.

Exploring the solid-state interfacial reaction of Al/Fe2O3 nanothermites by thermal analysis

In this study, we use simultaneous differential scanning calorimetry and thermogravimetric analysis to analyze the solid-state reaction characteristics of Al/Fe2O3 nanothermites before n-Al melts. Different experimental setups for thermal analysis are compared, and the heat-release characteristics are studied on Al/Fe2O3 nanothermites in the form of powder and pellet, respectively. It is found that protection provided by mere argon flow is far from enough for thermal analysis of Al/Fe2O3 nanothermites. The experimental setup must be free of oxygen; otherwise, the determined exothermic peak is mostly the oxidation of n-Al by the residue oxygen molecules in the furnace body, due to the high reactivity and moderate accessibility of free oxygen molecules. Under proper experimental setup, it is found that besides the redox reaction between n-Al and n-Fe2O3, intermetallic reaction also occurs to form Fe4Al13. Moreover, the intermetallic reaction is more noticeable for nanothermite pellet than for nanothermite powder, and the eutectic reaction of Fe4Al13 and n-Al leads to melting peaks below 655 °C. The results indicate that instrument configuration and sample status affect the testing results to a large extent, and one should be prudent to derive reaction characteristics of nanothermites.

Interdependencies between graphitization of carbon nanotubes and strengthening mechanisms in titanium matrix composites

Titanium (Ti) metal matrix composites (TMCs) reinforced with multi-walled carbon nanotubes (MWCNTs) were fabricated by powder metallurgy. Different concentrations (0.5 and 1.0 wt.%) of MWCNTs were dispersed into Ti powder by high energy ball milling (HEBM) and solution ball milling (SBM) processes. The solid-state interfacial reactions between dispersed MWCNTs and Ti matrices were controlled through altering the ball milling parameters and conditions. The powder mixtures were consolidated and sintered at 1100 °C in a vacuum furnace. The graphitization of MWCNTs and its strengthening efficiency in the fabricated TMCs were quantitatively characterized. The relationships between the graphitization and the key strengthening mechanisms were determined. The Ti-0.5 wt.% MWCNTs composites with in-situ TiC nanorods during HEBM and debundling of MWCNTs during SBM processes exhibited compressive yield strength of 882 and 920 MPA which demonstrated 18 and 32% increase compared to commercially pure titanium (CP-Ti), respectively. The key strengthening mechanisms included grain refinement, dispersion strengthening of homogenously dispersed MWCNTs and in-situ TiC particles, solid solution strengthening of carbon, oxygen and nitrogen in Ti matrix, and load-bearing strengthening in TMCs.

Kinetic study of solid-state interfacial reactions of p-type (Bi,Sb)2Te3 thermoelectric materials with Sn and Sn–Ag–Cu solders

P-type (Bi,Sb)2Te3 material system is extensively used in commercial thermoelectric (TE) applications. Soldering is commonly applied to fabricate bulk TE elements into TE modules. This study carefully examined the solid-state interfacial reactions of the commercial (Bi,Sb)2Te3 substrate with Sn and Sn–3.0Ag–0.5Cu solders. The joining plane was along the c-axis of the highly oriented [1 1 0] TE substrate. For the reactions with pure Sn solder, both the intermetallic compounds (IMCs) of SnTe and SnSb were rapidly formed at the interface. Most importantly, it was clearly demonstrated that both of them exhibited a linear growth with the aging time. The growth rates of SnTe and SnSb were 15.1 μm/h and 4.3 μm/h, respectively, at 180 °C. The IMC growth kinetics was further investigated systematically. The activation energies for the SnTe and SnSb growths were 151.6 kJ/mol and 165.3 kJ/mol, respectively. For the Sn–3.0Ag–0.5Cu/(Bi,Sb)2Te3 reaction, the SnTe and SnSb were also formed simultaneously. Similarly, they also had a linear growth, but their growth rates were significantly suppressed. A thin stripe-like Ag-rich phase was formed at the SnTe/(Bi,Sb)2Te3 interface, which could be the cause of the suppression of IMC growth. Additionally, minor addition of 0.1 wt.% Ga in Sn was also found to effectively suppress the interfacial IMC growth.

Synthesis of barium-strontium titanate hollow tubes using Kirkendall effect

(BaSr)TiO3 hexagonal hollow tubes was fabricated by a solid-state interfacial reaction including a Kirkendall diffusion. Using a co-precipitation and sol-gel process, a core@shell structure of (BaSr)CO3@TiO2 rods were prepared, and then converted to (BaSr)TiO3 hollow tubes at 750 °C. This was a first achievement of single-phase crystal hollow tube. Here, the inner diameter and wall thickness of hollow tube were about 700 nm and 130 nm, respectively. The fabrication of (BaSr)TiO3 hollow tubes was monitored with scanning electron microscopy (SEM), energy-dispersive spectrometry (EDS), transmission electron microscopy (TEM), and X-ray diffraction (XRD) to investigate their formation mechanism. The present synthetic approach would provide a new insight into the design and fabrication of hollow architectures of many perovskite oxides.

Effects of Ag addition on solid–state interfacial reactions between Sn–Ag–Cu solder and Cu substrate

Low–Ag–content Sn–Ag–Cu (SAC) solders have attracted much recent attention in electronic packaging for their low cost. To reasonably reduce the Ag content in Pb–free solders, a deep understanding of the basic influence of Ag on the SAC solder/Cu substrate interfacial reaction is essential. Previous studies have discussed the influence of Ag on the interfacial intermetallic compound (IMC) thickness. However, because IMC growth is the joint result of multiple factors, such characterizations do not reveal the actual role of Ag. In this study, changes in interfacial IMCs after Ag introduction were systemically and quantitatively characterized in terms of coarsening behaviors, orientation evolution, and growth kinetics. The results show that Ag in the solder alloy affects the coarsening behavior, accelerates the orientation concentration, and inhibits the growth of interfacial IMCs during solid–state aging. The inhibition mechanism was quantitatively discussed considering the individual diffusion behaviors of Cu and Sn atoms, revealing that Ag inhibits interfacial IMC growth primarily by slowing the diffusion of Cu atoms through the interface.