SYNTHESIS OF TIN POWDER BY USING PULSE CURRENT ELECTROLYSIS METHOD

• Main Author: Kudratzat, Tuah
• Format: Final Project
• Language: Indonesia
• Subjects: Metalurgi
• Online Access: https://digilib.itb.ac.id/gdl/view/51403
• Institution: Institut Teknologi Bandung

Global demand for electronic equipment increases along with the advancement of digital technology. This electronic equipment cannot be separated from solder usage in circuit board installations. Solders are used in the form of wire which is a mixture of 63% tin and 37% lead. The usage of lead-containing solder is considered detrimental to environment because of lead toxicity; there fore the demand for improvement of lead-free solder increases. One of the methods of synthesizing tin powder is by electrolysis method. The electrolysis method has the advantage of producing small size tin powder and offers a relatively lower investment and operational costs. On the other hand, electrolysis method has a weakness in producing tin powder with spherical grain morphology. As an endeavor to answer to the facts and problems stated above, this research focuses on tin powder synthesis by using pulse current electrolysis method. Electrolyte solution was prepared by dissolving 4.25 gram of SnSO4 in 850 mL of 1M H2SO4 to obtain 2.75 gram per liter Sn concentration. Electrolysis experiments were carried out in 2 stages using tin anodes and titanium cathodes. The variables employed are current density, mass ratio of thiourea/gelatin as additives, frequency, and duty cycle. The first stage of experimental works was designed and the data was analyzed by Taguchi Method to determine the optimum experimental conditions. Meanwhile, the second stage of experimental works used factorial method to determine the effects of each experimental variable. Tin powder synthesized from the electrolysis process was stored in vacuum plastic to prevent the exposure to the air and to minimize oxidation. Tin powder was then analyzed by Particle Size Analyzer (PSA), Scanning Electron Microscope (SEM), Energy-dispersive X-ray Spectroscopy (EDS), and X-ray Diffraction (XRD) to determine the size, morphology, oxidation level and its crystal orientation. The cathode interface potential measurements were also carried out by using Ag/AgCl standard electrode to determine the interface voltage of the cathode surface during the electrolysis. The results from electrolysis experiments showed that higher current density decreased the size of tin powder, while the morphology was initially spherical or spheroidal and, in the end, became granular or irregular. The higher mass ratio of thiourea/gelatine, the larger the powder size became, until it reached the maximum level where the morphology of the grain started from spherical or spheroidal and ended as globular. Frequency and duty cycle affected the size from toff time span, in which the longer toff enlarged the powder size until a certain maximum level. Meanwhile, the longer ton tends to convert the grain morphology to be spherical or spheroidal and then turned into globular or even shard-like or sharp-like.