Corrosion Resistance Of Sn Research Articles

Microstructure and properties of tin-cobalt nanocomposite coatings reinforced by titanium dioxide nanoparticles

Sn–Co binary alloy coatings are widely used as substitutes for chromium coatings in many aspects of modern industry. In this research, TiO2 nanoparticles were incorporated into the matrix of Sn–Co coatings aiming to enhance coating performance. The microstructure, mechanical properties and corrosion resistance of Sn–Co–TiO2 coatings were investigated systematically. The results found that the content of TiO2 nanoparticles imposed significant effects on the microstructure and properties of Sn–Co TiO2 coatings. Comparing with Sn–Co film, Sn–Co–1 g l−1 TiO2 coating has an increased microhardness of ∼409 HV. Also, the corresponding wear resistance and corrosion behavior of coatings were enhanced as well. The strengthening mechanism could be attributed to the structural evolution of coatings along with the addition of TiO2 nanoparticles. The relationships among TiO2 nanoparticles concentration, microstructure and properties were discussed in detail.

Effect of graphene nano-sheets additions on the density, hardness, conductivity, and corrosion behavior of Sn–0.7Cu solder alloy

Graphene nano-sheets (GNSs) are considered a functional (excellent/good) material at solder alloy modification. In this study, GNSs were doped into Sn–0.7Cu solder by powder metallurgy to form Sn–0.7Cu–xGNSs (x = 0.025, 0.05, 0.075, 0.1 wt%) composite solders. The density, hardness, and electrical conductivity of the composite solders were investigated. At the same time, Potentiodynamic polarization method, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM) were applied to analyze the electrochemical corrosion behavior of composite solders in the 3.5 wt% NaCl solution. The results revealed that as the content of GNSs increased, the hardness of composite solders decreased, but the density enhanced when compared with original Sn–0.7Cu. Simultaneously, the conductivity reached highest as the GNSs content was 0.025 wt%. Potentiodynamic polarization showed that GNSs affected the anodic reaction of the solders. The corrosion resistance of Sn–0.7Cu–0.075GNSs was better than that of other alloys. Sn3O(OH)2Cl2 and Tin oxides were the formation of the corrosion product by XPS and XRD analysis. SEM analysis confirmed that when the GNSs content was 0.075 wt%, the corrosion products were dense and the corrosion resistance of the alloy was improved.

Effect of Zn incorporation on the electrochemical corrosion properties of SAC105 solder alloys

The corrosion behaviour of lead-free solder alloy, Sn–1.0Ag–0.5Cu–XZn (X = 0, 0.1, 0.5, 1.0) was investigated by polarization, electrochemical impedance spectroscopy, scanning electron microscopy, energy dispersive spectrometry and X-ray diffractometry upon exposure in 3.5 wt% NaCl solution. The polarization curves showed that the addition of Zn in SAC105 solder alloy increased the corrosion current density and shifted the corrosion potential towards more negative values. The corrosion resistance of Sn–1.0Ag–0.5Cu–XZn alloys was reduced with the increase of Zn concentration. The EIS results were in consistent with the findings obtained from polarization curves. The corrosion products detected on the surface includes Sn3O(OH)2Cl2, SnO, SnO2 and ZnO.

Enhancement on the high-temperature joint reliability and corrosion resistance of Sn–0.3Ag–0.7Cu low-Ag solder contributed by Al2O3 Nanoparticles (0.12 wt%)

In this study, the evolution of interfacial microstructures and mechanical properties of the joints soldered with Sn–0.3Ag–0.7Cu (SAC0307) and SAC0307-0.12Al2O3 nanoparticles (NPs) aged at 150 °C for different hours (72–840 h) were investigated. It was found the joint soldered with SAC0307-0.12Al2O3 displayed a significantly enhanced high-temperature joint reliability, reflected in a higher shear force than that of the original. This enhancement in shear force primarily benefited from the refinement in solder microstructure contributed by Al2O3 NPs. As aging time reached 840 h, a controlled growth of interfaical IMC layer resulted from the pinning effect of Al2O3 NPs contributed to the increase in shear force. Theoretical analysis showed 0.12 wt% Al2O3 NPs effectively lowered the growth constant of total interfacial IMCs (DT) from 3.19 × 10−10 to 1.02 × 10−10 cm2 s−1. Moreover, comparative studies on the corrosion resistances of SAC0307 and SAC0307-0.12Al2O3 were also conducted by electrochemical test and analyzed by electrochemical impedance spectroscopy (EIS). The results revealed SAC0307-0.12 Al2O3 solder displayed a stronger corrosion resistance (Rt; ~ 3.1 kΩ cm2 vs ~ 7.1 kΩ cm2). This is also related with the tailored microstructure, which provides more grain boundaries for the initial nucleation of passive film.

Effects of In addition on the wettability, interfacial characterization and properties of ternary Sn–Cu–Ni solders

The thermal behavior, wettability, corrosion resistance, microhardness and interfacial reaction of quaternary Sn–0.7Cu–0.1Ni–xIn (x = 0, 0.5, 1.0 and 2.0 mass%) lead-free solder alloys were explored to reveal the effect of the indium (In) addition into the Sn–0.7Cu–0.1Ni solder on the properties of the solder alloy in the present investigation. The tested results revealed that the addition of small amount of In could lower both solidus and liquidus temperatures of the solder alloys. Moreover, the wettability of the solder alloy was remarkably improved by adding In element. The spreading area of Sn–0.7Cu–0.1Ni–1In was enhanced by 37% compared to that of Sn–0.7Cn–0.1Ni solder, meanwhile, the wetting angle of Sn–0.7Cu–0.1Ni solder was reduced by 39.1% with the addition of 2.0 wt% In. The intermetallic compound (IMC) formed between Sn–0.7Cu–0.1Ni–xIn solders and copper substrate was identified as (Cu,Ni)6Sn5 compound layer. The thickness and grains size of the IMC were slightly effected by the addition of In. The corrosion resistance of Sn–0.7Cu–0.1Ni–xIn solders increased with the addition of In, and the corrosion rate of Sn–0.7Cu–0.1Ni–1In solder was reduced by 62.8% compared with that of Sn–0.7Cu–0.1Ni solder in the 6% hydrochloric acid solution at ambient temperature for 14 days. Moreover, the hardness showed a decline of 14.7% when 2.0 wt% In was added into the Sn–Cu–Ni solder.

Effect of Cu and Ni Addition on Microstructure and Wettability of Sn-Zn Solders

In present study, Sn–9Zn, Sn–9Zn–xCu and Sn–9Zn–xNi solders (x = 1.0, 2.0 and 3.0 wt%) were prepared via melting process. Effects of Cu and Ni addition on microstructure, thermal behavior, wettability and corrosion resistance of Sn–9Zn solders were investigated. The experimental result showed that microstructure of the Sn–9Zn was composed of β–Sn and Zn–rich phases. Addition of Cu to the Sn–9Zn solders, Cu6Sn5 and Cu5Zn8 IMCs were observed. While addition of Ni to the Sn–9Zn solders, Ni3Sn4 and Ni5Zn21 IMCs were observed. It was also found that, amount of those IMCs obviously increased with increasing of Cu and Ni contents. The results obtained from thermal analysis showed that melting temperature of the Sn–9Zn solder was 199.6°C. While melting temperatures of the Sn–9Zn–1.0Cu and Sn–9Zn–1.0Ni solders were 199.9°C and 204.2°C, respectively. The Cu and Ni contents had little effect on both spread rate and wetting angle of the Sn–9Zn–xCu and Sn–9Zn–xNi solders. However, increasing of Cu and Ni contents significantly increased the corrosion potentials of the Sn–9Zn–xCu and Sn–9Zn–xNi solders.

Effects of Phosphorus Addition on the Corrosion Resistance of Sn–0.7Cu Lead-Free Solder Alloy

The corrosion behavior of Sn–0.7Cu–xP (x = 0, 0.1, 0.3, 0.5) solder alloy in the aggressive environment was investigated by potentiodynamic polarization and weight loss method. Scanning electron microscope (SEM) was used to observe the morphology of Sn–0.7Cu–xP solder alloys and X-ray diffraction (XRD) was applied to characterize the phases formed on the surface after corrosion. The results indicate that phosphorus (P) can enhance the corrosion resistance of Sn–0.7Cu solder alloy whether in acidic or in alkaline solution, and its corrosion resistance increases with increasing P. The corrosion resistance of the solder alloy is better in alkaline solution compared to that in acidic solution. The morphology observation also shows that the incorporation of P into Sn–0.7Cu alloy can obviously decrease the damage extent of the solder alloys. XRD analysis reveals that the corrosion products both in acidic and alkaline solution are Sn oxides.

Evaluation of cooling rate on electrochemical behavior of Sn–0.3Ag–0.9Zn solder alloy in 3.5 wt% NaCl solution

The corrosion resistance of Sn–0.3Ag–0.9Zn alloy solidified under different cooling rates in 3.5 wt% NaCl solution was evaluated based on potentiodynamic polarization, electrochemical impedance spectroscopy and electrochemical noise. It is found that the corrosion resistance of this alloy improves with the increase of the applied cooling rate, which is attributed to the distinct microstructure. The furnace-cooled and air-cooled alloy with active Zn-rich phase and a microstructure formed by a coarser dendritic array associated with larger size of AgZn3 intermetallic compounds exhibit a worse corrosion resistance due to a serious galvanic corrosion. Besides, the Mott–Schottky measurement and the X-ray photoelectron spectroscopy were performed to analyze the semiconductor properties and composition of the passive film formed on the surface of the alloy. It confirms that the stability and protective ability of the passive films formed on furnace-cooled and air-cooled alloy are worse than that of water-cooled alloy due to their higher oxygen vacancy defects and concentration of unstable SnO. Furthermore, the major corrosion product on the surface of the Sn–0.3Ag–0.9Zn alloys is tin oxide chloride hydroxide.