In-Situ Study of Electrochemical Migration of Tin in The Presence of Bromide Ion

The miniaturization of electronic devices and the consequent decrease in the distance between conductive lines have increased the risk of short circuit failure due to electrochemical migration (ECM). The presence of ionic contaminants in the devices can accelerate the ECM process. This work systematically investigates the ECM of tin (Sn) in the presence of bromide ions (Br−) in the range of 10-6 M to 1.0 M. Water drop test (WDT) was conducted in the two-probe semiconductor characterization system under an optical microscope for in-situ observations. Anodic polarization test (APT) was carried out to study the correlation between corrosion properties of Sn and its ECM behaviour. The products of ECM were characterized by scanning electron microscope coupled with an energy dispersive X-rays spectrometer (SEM/ EDX) and X-ray photoelectron spectrometer (XPS). The results confirm that the rate of anodic dissolution of Sn monotonously increases with Br− concentration. However, the probability of ECM failure follows a normal distribution initially, but later increases with the Br− concentration. The main products of the ECM reactions are identified as Sn dendrites and tin hydroxide precipitates. The mechanism of the ECM process of Sn in the presence of Br− is also suggested.

Effect of Phosphorus and Nickel on Electrochemical Migration of Sn-3Ag-0.7Cu Solder Paste in Simulated Body Fluid

Electrochemical migration (ECM) behaviour of Sn-3Ag-0.7Cu and Sn-3Ag-0.7Cu-0.03P-0.005Ni solder alloys were investigated using simulated body fluid (SBF) solution. In electronic devices, ECM phenomenon potentially leads to incompetence or failure of the whole devices. According to water drop test (WDT), mean-time-to-failure (MTTF) of commercially used Sn-3Ag-0.7Cu solder alloy was prolonged with addition of phosphorus (P) and nickel (Ni) as alloying elements. According to microstructure of each solder paste alloy which was observed using field emission scanning electron microscope (FESEM), dendrite structure in Sn-3Ag-0.7Cu-0.03P-0.005 Ni solder was lesser than in plain the Sn-3Ag-0.7Cu. This phenomenon suggested that presence of P and Ni retarded the growth of dendritic thus improved its corrosion resistance. Therefore, Sn-3Ag-0.7Cu-0.03P-0.005Ni possessed a good corrosion resistance in SBF medium.

Rapid functionalisation of cellulose-based materials using a mixture containing laccase activated lauryl gallate and sulfonated lignin

An innovative method has been developed for the surface hydrophobisation of cellulose-based materials by coating it with a functionalised solution (FS), in which sonicated lauryl gallate (LG, dodecyl 3,4,5,-trihydroxybenzoate), sulfonated kraft lignin, and the enzyme laccase play a pivotal role. The rapid treatment with FS increases the hydrophobicity of cellulose sheets considerably. The FS retention on the paper surface was analysed as a function of refining and application of additives. The properties of the functionalised sheets were assessed by the water-drop test (WDT), and the surface free energy (SFE) was determined via contact angle (CA) measurements in a goniophotometer. WDT resulted in long absorption times of up to 4000 s and CA values were around 130°. Functionalised solution modification of eucalyptus paper sheets decreased SFE essentially from 55 mJ m-2 to 10 mJ m-2. ATR-FTIR suggested that FS was grafted onto the cellulosic sheets. The stability of FS and the control solutions were characterised by Z potential and light scattering measurements. The functionalised solution method is a one-step roll-to-roll process, which is easy to perform also in industrial application without additional investments. It has a potential to substitute the traditional hydrophobing processes.

The Evaluation of Certain Organic Nitrogen Compounds As Corrosion Inhibitors★

The Static Water Drop Test adapted to research methods has been utilized to evaluate the corrosion inhibiting ability of a number of heterocyclic nitrogen compounds. Most of these heterocyclic N derivatives were synthesized and purified and evaluated in a petroleum-type lubricating oil and a synthetic diester-type lubricating oil. The effect of various functional groups and their positions in the molecule was related to the corrosion inhibiting properties. It was found that the adsorptive power was a function of the heterocyclic nitrogen containing a hydrogen atom as the substituent. It was also found that the adsorptive power at the heterocyclic nitrogen atom was lost when other substituents replaced the hydrogen. It was concluded that the adsorptive effect of the heterocyclic nitrogen is due to its unshared electron pair, which is sterically hindered when substituents other than hydrogen are attached. N-Hydroxyalkyl derivatives in diester oil seemed to arrange themselves in order of effectiveness on the basis of the position of the hydroxyl group in the alkyl chain. The closer the hydroxyl was to the heterocyclic nitrogen the more effective it was as a corrosion inhibitor. There was no way to explain the order of effectiveness of the same compounds in petroleum oil. 5.8.1

A Laboratory Study of N-Oleoyl Sarcosine As a Rust Inhibitor in Some Petroleum Products★

Laboratory studies indicate that N-oleoyl sarcosine (I) is an effective oil soluble rust inhibitor in solution in gasoline, mineral oil and silicone lubricants. Rusting tests used included: Turbine Oil Rusting Test (ASTM D665-54), a Static Immersion Test, Humidity Cabinet Test (JAN H-792), Static Water Drop Test (MIL-L-17353 Bu. Ord.). In addition, a number of auxiliary tests were run to indicate the effect of (I) on other properties of the test liquid. Hydrocarbon solutions of N-oleoyl sarcosine are particularly effective in preventing rusting in the presence of synthetic sea water and in resisting water extraction of the inhibitor. 5.8.2