PROBLEMS OF IMPROVING THE RELIABILITY AND QUALITY OF RADIO ELECTRONIC PRODUCTS AND INSTRUMENTS WHEN USING LEAD-FREE SOLDERS

Author(s):  
Н.В. Астахов ◽  
А.В. Башкиров ◽  
О.Ю. Макаров ◽  
А.А. Пирогов ◽  
А.С. Демихова

Обеспечение надежности и качества радиоэлектронных средств и приборов - это одна из главных задач в процессе проектирования новых устройств. Благодаря высокому качеству паяных соединений увеличивается срок службы электронных изделий, а также их безотказность в процессе эксплуатации и ремонтопригодность. Также нужно не забывать об экологической безопасности производимых устройств. В связи со всем вышеизложенным наиболее перспективно проводить исследования и искать практические решения возникающих трудностей в сфере технологий, в которых используются бессвинцовые припои, что позволит соблюсти современные требования к электронной аппаратуре. Кратко изложены основные последствия и проблемы применения чисто бессвинцовой пайки, рассмотрены проблемы применения смешанной технологии пайки и исследование эффекта роста оловянных «усов». Сделан вывод о том, что избежать большинства дефектов помогает применение активных флюсов, сохраняющих свои свойства при высоких температурах, пасту необходимо выбирать с тем условием, что в ее составе не должно быть канифоли, которая начинает активно выделяться в виде газа при повышении температуры, следует также верно подбирать температурный профиль пайки. Среди финишных покрытий лучше всего себя зарекомендовали иммерсионное серебро и никель-золото. Применение в припое в качестве заменителей свинца таких металлов, как висмут и индий существенно повышает стоимость припоев. Отмечается, что хорошие показатели имеют припои с содержанием цинка, однако цинк приводит к невозможности долгосрочного хранения паяльных паст, повышению оксидирования, необходимости пайки в среде инертных газов и с применением активных флюсов Ensuring the reliability and quality of radio-electronic equipment and devices is one of the main problems in the process of designing new devices. Due to the high quality of soldered joints, the service life of electronic products increases, as well as their reliability during operation and maintainability. It is also necessary not to forget about the environmental safety of the manufactured devices. In connection with all the above, it is most promising to conduct research and look for practical solutions to the emerging difficulties in the field of technologies that use lead-free solders, which will allow us to meet modern requirements for electronic equipment. The article briefly describes the main consequences and problems of using pure lead-free soldering, the problems of using mixed soldering technology, and the study of the effect "whiskers". Use of active fluxes that retain their properties at high temperatures helps to avoid most defects, the paste should be chosen with the condition that it should not contain rosin, which begins to actively emit as a gas when the temperature rises, and the temperature profile of soldering should also be correctly selected. Among the finishing coatings, immersion silver and nickel-gold proved to be the best. The use of metals such as bismuth and indium in solder, as lead substitutes, significantly increases the cost of solders. The article also notes that solders with a zinc content have good indicators but zinc leads to the impossibility of long-term storage of soldering pastes, increased oxidation, the need for soldering in an environment of inert gases and with the use of active fluxes

2020 ◽  
Vol 35 ◽  
pp. 04021
Author(s):  
Victor V. Shcherbinin ◽  
Ravil R. Zagidullin ◽  
Georgy A. Kvetkin ◽  
Marina S. Sidorova

The paper proposes ways to reduce the time and improve the quality of development of electronic equipment using computer simulation. The paper considers an example of the development and debugging of a radio-electronic module, which has found its direct application in a local navigation system that operates on the basis of the method of point landmarks. The paper considers a hardware-software complex for the implementation of the study of the health of both individual functional units and radio rangefinder equipment as a whole, as well as for the modernization of the radio-electronic module of the navigation system. The various computer simulation environments available today allow the development and design of electronic equipment at various levels. In the proposed work, computer simulation was carried out in MATLAB / Simulink, LabVIEW, Multisim and MicroCap. The work also provided for the possibility of using data collection and processing modules, which provides the opportunity in one software development and modeling environment to compare the results obtained using simulation modeling and physical research of the object. The result of the work is a hardwaresoftware kit of the radio-electronic module of the navigation system through which it is possible to evaluate the influence of various external influences on the accuracy of determining the range from the interrogator (moving object) to the transponder (stationary beacon).


Author(s):  
Shidong Li ◽  
Minghui Lin ◽  
Mohd F. Abdulhamid ◽  
Cemal Basaran

Many factors such as high intensity current, thermal load, shock load, vibration load and etc., can induce the failure in electronic equipment. It is common for electronic equipment to be subjected to a combination of the loads mentioned above simultaneously. In this paper, qualitative finite element simulations of thermomigration induced strain fields in lead free solders are conducted using a fully coupled displacement-diffusion model [1] with nonlinear mechanical material properties. The solutions are discussed and compared to experimental data as well as theoretical developments from literature.


2005 ◽  
Vol 2 (1) ◽  
pp. 72-83 ◽  
Author(s):  
Jianbiao Pan ◽  
Jyhwen Wang ◽  
David M. Shaddock

There is an increasing demand for replacing tin-lead (Sn/Pb) solders with lead-free solders in the electronics industry due to health and environmental concerns. The European Union recently passed a law to ban the use of lead in electronic products. The ban will go into effect in July of 2006. The Japanese electronics industry has worked to eliminate lead from consumer electronic products for several years. Although currently there are no specific regulations banning lead in electronics devices in the United States, many companies and consortiums are working on lead-free solder initiatives including Intel, Motorola, Agilent Technologies, General Electric, Boeing, NEMI and many others to avoid a commercial disadvantage. The solder joints reliability not only depends on the solder joint alloys, but also on the component and PCB metallizations. Reflow profile also has significant impact on lead-free solder joint performance because it influences wetting and microstructure of the solder joint. A majority of researchers use temperature cycling for accelerated reliability testing since the solder joint failure mainly comes from thermal stress due to CTE mismatch. A solder joint failure could be caused by crack initiation and growth or by macroscopic solder facture. There are conflicting views of the reliability comparison between lead-free solders and tin-lead solders. This paper first reviews lead-free solder alloys, lead-free component lead finishes, and lead-free PCB surface finishes. The issue of tin whiskers is also discussed. Next, lead-free solder joint testing methods are presented; finite element modeling of lead-free solder joint reliability is reviewed; and experimental data comparing lead-free and tin-lead solder joint reliability are summarized. Finally the paper gives perspectives of transitions to totally lead-free manufacturing.


2011 ◽  
Vol 189-193 ◽  
pp. 3230-3237 ◽  
Author(s):  
Huan Liu ◽  
Feng Xue ◽  
Jian Zhou

The effects of fluxes with different activators (sebacic acid and diethylamine hydrochlcoride) on the wetting behavior of Sn-Zn lead-free solders were investigated. The wettability tests showed that fluxes with the addition of single sebacic acid or diethylamine hydrochlcoride significantly improved wettability of Sn-Zn solder on Cu substrate. However, fluxes with combined additions of above activators promoted wetting performance of the solder further. Thermal analysis (thermal-gravimetry analyzer and differential scanning calorimeter) results demonstrated that the effective temperature range of diethylamine hydrochlcoride is higher than that of sebacic acid. So diethylamine hydrochlcoride could react with oxides on the solder and substrate surfaces at a wider temperature range which resulted in an enhanced spreading of solders. Scanning electron microscopy (SEM) image showed that two kinds of diffusion layers were formed between Sn-Zn solder and Cu substrate, indicating fluxes with binary activators markedly improved welding quality of Sn-Zn solder.


2007 ◽  
Vol 38 (3) ◽  
pp. 245-258 ◽  
Author(s):  
Leonid L. Vasiliev ◽  
Andrei G. Kulakov ◽  
L. L. Vasiliev, Jr ◽  
Mikhail I. Rabetskii ◽  
A. A. Antukh

2015 ◽  
Vol 10 (1) ◽  
pp. 2641-2648
Author(s):  
Rizk Mostafa Shalaby ◽  
Mohamed Munther ◽  
Abu-Bakr Al-Bidawi ◽  
Mustafa Kamal

The greatest advantage of Sn-Zn eutectic is its low melting point (198 oC) which is close to the melting point. of Sn-Pb eutectic solder (183 oC), as well as its low price per mass unit compared with Sn-Ag and Sn-Ag-Cu solders. In this paper, the effect of 0.0, 1.0, 2.0, 3.0, 4.0, and 5.0 wt. % Al as ternary additions on melting temperature, microstructure, microhardness and mechanical properties of the Sn-9Zn lead-free solders were investigated. It is shown that the alloying additions of Al at 4 wt. % to the Sn-Zn binary system lead to lower of the melting point to 195.72 ˚C.  From x-ray diffraction analysis, an aluminium phase, designated α-Al is detected for 4 and 5 wt. % Al compositions. The formation of an aluminium phase causes a pronounced increase in the electrical resistivity and microhardness. The ternary Sn-9Zn-2 wt.%Al exhibits micro hardness superior to Sn-9Zn binary alloy. The better Vickers hardness and melting points of the ternary alloy is attributed to solid solution effect, grain size refinement and precipitation of Al and Zn in the Sn matrix.  The Sn-9%Zn-4%Al alloy is a lead-free solder designed for possible drop-in replacement of Pb-Sn solders.  


2013 ◽  
Vol 58 (2) ◽  
pp. 529-533 ◽  
Author(s):  
R. Koleňák ◽  
M. Martinkovič ◽  
M. Koleňáková

The work is devoted to the study of shear strength of soldered joints fabricated by use of high-temperature solders of types Bi-11Ag, Au-20Sn, Sn-5Sb, Zn-4Al, Pb-5Sn, and Pb-10Sn. The shear strength was determined on metallic substrates made of Cu, Ni, and Ag. The strength of joints fabricated by use of flux and that of joints fabricated by use of ultrasonic activation without flux was compared. The obtained results have shown that in case of soldering by use of ultrasound (UT), higher shear strength of soldered joints was achieved with most solders. The highest shear strength by use of UT was achieved with an Au-20Sn joint fabricated on copper, namely up to 195 MPa. The lowest average values were achieved with Pb-based solders (Pb-5Sn and Pb-10Sn). The shear strength values of these solders used on Cu substrate varied from 24 to 27 MPa. DSC analysis was performed to determine the melting interval of lead-free solders.


Author(s):  
I. A. Ilina ◽  
I. A. Machneva ◽  
E. S. Bakun

  The article is devoted to the study of the chemical composition, physical and thermal-pfysical characteristics of damp apple pomaces and the identifying patterns of influence of drying temperature the functional composition and gel-forming ability of pectin. The research is aimed at obtaining initial data for the subsequent calculation of the main technological, hydro-mechanical, thermal, structural and economic characteristics of devices for drying the plant raw materials, ensuring the environmental safety and high quality of pectin-containing raw materials, the reducing heat and energy costs. As a result of the study of the thermal characteristics of apple pomaces, the critical points (temperature conductivity – 16.5 x 10-8 m2/s, thermal conductivity – 0.28 W/m K, heat capacity – 1627 j/(kg K)) at a humidity of 56 % are determined, which characterizing the transition from the extraction of weakly bound moisture to the extraction of moisture with strong bonds (colloidal, adsorption). It was found that the pomaces obtained from apples of late ripening have a higher content of solids (21-23 %), soluble pectin and protopectin (2.5-4.5 %). Dried pomaces obtained from apple varieties of late ripening contain up to 25 % pectin, which allow us to recommend them as a source of raw materials for the production of pectin. The optimum modes of preliminary washing of raw materials are offered, allowing to the remove the ballast substances as much as possible. It is established that when the drying temperature increases, the destructive processes are catalyzed: the strength of the pectin jelly and the uronide component and the degree of pectin esterification are reduced. The optimum drying temperature of damp apple pomaces is 80 0C, at which the quality of pectin extracted from the dried raw materials is maintained as much as possible. It is shown that the most effective for the pectin production is a fraction with a particle size of 3-5 mm, which allow us to extract up to 71 % of pectin from raw materials.


Author(s):  
Chris Muller ◽  
Chuck Arent ◽  
Henry Yu

Abstract Lead-free manufacturing regulations, reduction in circuit board feature sizes and the miniaturization of components to improve hardware performance have combined to make data center IT equipment more prone to attack by corrosive contaminants. Manufacturers are under pressure to control contamination in the data center environment and maintaining acceptable limits is now critical to the continued reliable operation of datacom and IT equipment. This paper will discuss ongoing reliability issues with electronic equipment in data centers and will present updates on ongoing contamination concerns, standards activities, and case studies from several different locations illustrating the successful application of contamination assessment, control, and monitoring programs to eliminate electronic equipment failures.


Author(s):  
O. Klepikov ◽  
S. Eprintsev ◽  
S. Shekoyan

Data of the Federal Information Fund for Social Hygiene Monitoring conducted on the basis of the Federal Center for Hygiene and Epidemiology of Rospotrebnadzor have been analyzed to assess environmental risks, as well as to develop environmental safety system as a factor for sustainable development of the territory in the regions of the Russian Federation. Atmospheric air pollution in Russian regions was evaluated by content of priority pollutants. Ranking of Russian regions according to the quality of drinking water supply was carried out. The possibility of using Federal Information Fund for Social Hygiene Monitoring as an integral part of the model for optimizing the social and environmental conditions of populated areas is estimated.


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