The use of periodic pulse reverse current allows to form tin-bismuth electroplated coatings, with high value of term storage stable solderability. The reseach results of the influence of nonstationary electrolysis on solderability of the Sn-Bi alloy coatings have been demonstrated. The appropriate conditions for obtaining high-quality lead-free coatings with high solderability have been found. The best mode is ik av = 1.0 A/dm2, ?forw: ?rever = 4:1, f= 0.1…1 Hz

Brantsevitch, V.

Khmyl, A.

Digital Library of Polotsk State University (Репозиторий Полоцкого государственного университета)

MATERIALS OF VI JUNIOR RESEARCHERS’ CONFERENCE                                                      2014 ICT, Electronics, Programming   123REFERENCES  1. Jakobsen, O.C. Control Architecture for a UAV – Mounted Pan/Tilt/Roll Camera Gimbal /AIAA Infotech@Aerospace, Arlington / O.C. Jakobsen, E.N. Johnson. – Virginia, Sep. 2005. – 7145 p. 2. Guenard, N. A practical Visual Servo Control for a Unmanned Aerial Vehicle / N. Guenard, T. Hamel, R. Mahony. // Proceedings of the IEEE international conference on robotics and automation ICRA, 2002. 3. Panagopoulos, H. PID Control Design, Extension, Application / H. Panagopoulos // PhD thesis, Department of automatic Control, Lund Institute of Technology, Lund, Sweden, 2000. 4. Xu, J. Design of Adaptive Fuzzy PID tuner using optimization method / J. Xu, X. Feng // The 5th World Congress onIntelligent Control and Automation, China, 2004. – P. 2454 –2458. 5. Zhang, J. A developed method of tuning PID controlle s with fuzzy rules for integrating process / J. Zhang, N. Wang, S. Wang. // The American Control Conference. – Boston, 2004. – P. 1109 – 1114. 6. Ang, K.H. PID control system analysis, design and technology / G. Chong, Y. Li // IEEE transaction on Contr l System Technology. – 2005. – Vol. 13. – No.4. – P. 559–576. 7. Mendel, J.M. Fuzzy Logic Systems for Engineering: A Tutorial / J.M. Mendel // Proceedings of the IEEE. – 1995. – Vol. 83. – No. 3– P. 345–377. 8. Zadeh, L.A. Fuzzy Logic, Neural Networks, and Soft Computing / L.A. Zadeh // Communication of the ACM. – 1994. – Vol. 3. – No. 3. – P. 77–84. 9. Chopra, S. Fuzzy controller: Choosing an appropriate & smallest rule set / S. Chopra, R. Mitra, V. Kumar // International Journal of Computational Cognition – 2005. – Vol. 3. – No. 4. – P. 73–78. 10. Vaishnav, S.R. Design of PID & Fuzzylogic controller for higher order system / S.R. Vaishnav, Z.J. Khan // International Conference on Control & Automation (ICCA'07), Hong Kong, China, 2007. – P. 1469 – 1472. 11. Yongquan, Y. The dynamic fuzzymethod to tune the weight factors of neural fuzzy PID controller / Y. Yongquan, H. Ying, Z. Bi. – IEEE, 2004. – P. 2397–2402. 12. Altas, H. A Generalized Direct Approach for Designing Fuzzy Logic Controllers in Matlab / Simulink GUI Environment / H. Altas, A.M. Sharaf. // International Journal of Information Technology and Intelligent.   UD 621.357.77  USING NONSTATIONARY ELECTROLYSIS FOR FORMATION SN-BI COATINGS  VIKTORYIA BRANTSEVITCH, ALEXANDER KHMYL Belarusian State University of Informatics and Radioelectronics, Belarus  The use of periodic pulse reverse current allows to form tin-bismuth electroplated coatings, with high value of term storage stable solderability. The reseach results of the influence of nonstationary electrolysis on solderability of the Sn-Bi alloy coatings have been demonstrated. The appropriate conditions for obtaining high-quality lead-free coatings with high solderability have been found. The best mode is ikav = 1.0 A/dm2, τforw: τrever = 4:1, f= 0.1…1 Hz.  Among the special electrochemical coatings with higquality and reliability of solder joints in electronic equipment, Sn-coatings are especially pointed out. However, pure Sn tends to spontaneously phase transformation at lw temperatures and during prolonged operation. Numerous bath composition  for formation of Sn-based alloys are developed in order to eliminate this phenomenon. Zinc, nickel, antimony, silver, copper, and bismuth are used as alloying components i those baths. Most economical and promising for conditions of mass production of microelectronics are Sn-Bi, Sn-Sb, Ag-Sn alloys [1]. However, existing processes for the formation of deposited by DC Sn-based coatings are inefficient (0,1-0,12 m / h), and don’t provide the desired solderability that decreases after three months of storage as a result of high value of porosity and low texturing of the coating. One way of solving this problem is the use of nonstationary electrolysis. As electrocrystallization current is one of the main factors determining the electrochemical and structural conditions for the cementation, so it can widely control quality of the coatings by changing current according to certain laws. Using periodic pulse reverse (PPR) current electroplating leads to changing of ordinary way of crystal formation, their growth and properties of coating. PPR current is sequentially alternating cathodic and anodic processes on one electrode. Periodic dissolving the most active portions of the cathode (usually protrusions) tends to equalize the surface, makes it moreuniform. In this case, number of lattice defects, porosity, and content of impurities in the precipitate are reduced [2]. Based on the above mentioned using nonstationary electro ysis for deposition Sn-Bi-coating is current and advanced affairs. The influence of nonstationary electrolysis was tested on the Sn-Bi-coating. Plating solution contained SnSO4 (50 g/l), Bi(NO3)3 (1.4 g/l), H2SO4 (125 g/l), neonol AF-9-10 (4 g/l), additive CCN-32 ( g/l), which was manufactured by research and production association «SEM.M». Coatings were plated at room temperature. MATERIALS OF VI JUNIOR RESEARCHERS’ CONFERENCE                                                      2014 ICT, Electronics, Programming   124Electrodeposition was performed by using developed BSUIR power supply SP 24-5. Power supply can form pulses of positive and negative polarity, whose parameters are set by the computer. According to GOST 9.302-88 the functional properties of coatings were investigated. Varying the parameters of PPR current leads to the formation of dense, uniform, fine-grained coatings (Fig. 1) and allows expanding the range of operating current densities. It has been established that the value of the solder spr ading factor is reduced from the value from 96% to 87% on a constant current (on the current density from 0.5 to 2 A/dm2). Solder spreading factor is index of solder wettability of the coatings. Also, this DC technology does not provide long-term storage of solderability due to its high porosity and a coarse crystalline structure.    а b  Fig. 1 The influence of DC (a) and PRC (b) (ikav=0.5 А/dm2, γ=1,67, f=0,1 Hz) on the structure of Sn-Bi coating  Reduction of solder spread factor with increasing current density occurs due to the quality degeneration of the coating under higher densities. The quality degen ration of surface is observed by using DC (ik =1.8 А/dm2). Using nonstationary electrolysis extends range of operating current densities and allows to increase limit of operating current and to form light metal coatings with high value of the solder spreading factor. Reseach of solderability after three months in laboratory condition was conducted. It has shown that using nonstation ry electrolysis leads to forming of coatings with high value of term storage stable solderability (tables 1…3).  Table 1 – Solderability of Sn-Bi pulse electrodeposited alloy (ikav = 0,5 А/dm2, f = 10 Hz)  Solder spreading factor, % f, Hz as-plated coatings stored Relative variation, % 1,25 91,8 77,3 15,8 2 91,5 81,9 10,5 2,5 90,9 86,2 5,2 3,33 89,0 82,6 7,2 5 91,3 84,8 7,1  Table 2 – Solderability of Sn-Bi PPR electrodeposited alloy (ikav = 0,5 А/dm2, γ = 1,67)  Solder spreading factor, % f, Hz as-plated coatings stored 0,1 89 76 1 91 78 10 90 83 100 84 70 1000 90 83  Table 3 – Solderability of Sn-Bi PPR electrodeposited alloy with different ratios of length of the forward and reverse pulse (ikav = 1,0 А/dm2, f = 1 Hz)  Solder spreading factor, % τforw: τrever as-plated coatings stored 3:1 94 88 4:1 93 88 10:1 83 80 20:1 92 89 It’s been established, that using PPR current allows to form Sn-Bi coatings with high value of solderability continuing long-term storage. MATERIALS OF VI JUNIOR RESEARCHERS’ CONFERENCE                                                      2014 ICT, Electronics, Programming   125Optimal conditions for obtaining high-quality lead-free coatings with high solderability were developed. The best PPR mode was selected: ikср = 1,0 А/dm2, τforw: τrev = 4:1, f=  0,1..1 Hz. The author would like to thank staff of the Research Laboratory № 10.2 of the research and development department at BSUIR for their support and contributions.  REFERENCES  1. Хмыль, А.А. Функциональные композиционные покрытия на основе олова / А.А Хмыль, Л.К Кушнер, В.А. Вакульчик // Труды международной научно-технической конференции «Энерго- и ресурсосберегающие технологии и оборудование, экологически безопасные технологии» БГТУ – Минск, 2010. – С. 192–195. 2. Хмыль, А.А. Формирование тонкопленочных систем металлизации в нестационарных условиях электролиза: Дисс. д-ра. техн. Наук / А.А Хмыль. – Минск, 2001.   UDC 501.503.3  MODERN TECHNOLOGIES IN TASKS OF WEATHER FORECASTING  TATSIANA STADUB, YURI LIVSHITS Belarusian National Technical University, Belarus  This article deals with modern technologies of processing of weather information. The model WRF (Weather Research and Forecasting) of weather forecasting is described in it.  In the atmosphere there are the diverse physical processes which are continuously changing its state. Th  physical condition of the atmosphere near the earth's surface and in the lower 30 – 40 km is called weath r. Data for a weather forecast are gathered from various sorces: meteorological stations, meteorological balloons, space satellites, etc. World centers of a weather forecast receive information from all over the world and compose global weather forecasts (fig. 1).    Fig. 1. Composition of global weather forecast  Weather forecasting are used synoptic, statistical and numerical methods. Synoptic method of forecasting is based on the analysis of weather charts. Statistic l forecasting methods allow the past and present tate of the atmosphere to predict the future state of the weather, i.e. predict changes in various meteorological parameters in the future. Numerical weather prediction (NWP) became a significant source for weather forecasts. NWP model is a modern set of computer programs that contains mathematical and physical equations / algorithms to describe 

Using nonstationary electrolysis for formation SN-BI coatings

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Using nonstationary electrolysis for formation SN-BI coatings

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