RoHS Research Articles

The Effects of Nickel Underlayer and Solder Dipping as Tin Whisker Mitigations in Tin Surface Finishes

Driven by environmental concerns and the enforcement of Restriction of Hazardous Substances Directive (RoHS) to ban the use of lead in electronics, the global electronics industry has migrated toward lead-free electronics. However, the adoption of lead-free tin (Sn) surface finish is known to form whiskers. These whiskers grow spontaneously from the Sn finish layer as a stress-relief over time causing device failures. In the present research, whisker growth is investigated via immersion Sn finishes on Cu substrate. The effects of Sn layer thickness, addition of Ni under-layer and solder dipping on whisker growth are investigated by storing the samples under ambient temperature for up to 24 weeks. The effects of external stresses were also studied using bending test. The results showed that whisker length on immersion Sn increases with time for all the samples either with or without Ni under-layer. Thicker Sn coating showed more whisker growth compared with thinner Sn coating. The longest whisker length of 23μm was observed for Sn coating with 2μm thickness. The addition of Ni as under-layer was found to be more effective in mitigating the whisker growth by extending the incubation time for whisker formation. Compared to immersion Sn, solder dipping in pure Sn showed no whisker growth. However, alloying Sn with 0.4%wtCu resulted in whisker growth indicating the role of Cu in promoting whiskers formation.

Assessment of toxic metals in waste personal computers

Considering the enormous production of waste personal computers nowadays, it is obvious that the study of their composition is necessary in order to regulate their management and prevent any environmental contamination caused by their inappropriate disposal. This study aimed at determining the toxic metals content of motherboards (printed circuit boards), monitor glass and monitor plastic housing of two Cathode Ray Tube (CRT) monitors, three Liquid Crystal Display (LCD) monitors, one LCD touch screen monitor and six motherboards, all of which were discarded. In addition, concentrations of chromium (Cr), cadmium (Cd), lead (Pb) and mercury (Hg) were compared with the respective limits set by the RoHS 2002/95/EC Directive, that was recently renewed by the 2012/19/EU recast, in order to verify manufacturers’ compliance with the regulation. The research included disassembly, pulverization, digestion and chemical analyses of all the aforementioned devices. The toxic metals content of all samples was determined using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). The results demonstrated that concentrations of Pb in motherboards and funnel glass of devices with release dates before 2006, that is when the RoHS Directive came into force, exceeded the permissible limit. In general, except from Pb, higher metal concentrations were detected in motherboards in comparison with plastic housing and glass samples. Finally, the results of this work were encouraging, since concentrations of metals referred in the RoHS Directive were found in lower levels than the legislative limits.

폐 LCD (Liquid Crystal Display) 해체 후 분리된 CCFL (Cold Cathode Fluorescence Light) 내 수은의 건식 제거 공정

LCD TV와 컴퓨터 모니터에는 스크린을 밝게 할 목적으로 냉음극관이 장치되어 있는데 이러한 냉음극관 대부분에는 수은이 봉입되어 있으므로 폐 LCD의 재활용 시 적절히 취급되어야 한다. 아울러 이러한 폐 LCD내의 냉음극관의 처리는 2002년에 채택된 EU의 WEEE 와 RoHS 지침에 따라 취급되고 제거되어야만 한다. 본 연구에서는 폐 LCD의 몰드 프레임에 장착된 CCFL을 안전하고 효율적으로 제거한 다음 여기 함유된 수은과 형광체 화합물을 환경친화적으로 분리하여 무해화 처리할 수 있는 건식 공정을 개발하였다. 이를 통해서 실용적이고 경제성 있는 폐디스플레이 자원 재활용 통합공정 개발에 기여할 목적으로 CCFL 무해화 시스템의 설계 및 제작, 이를 운용한 수은/형광체 화합물의 환경친화적 무해화 처리 효율을 평가해 보았다. CCFL 무해화 시스템을 이용하여 처리된 CCFL내 잔류 수은의 양을 정량적으로 평가해 본 결과 무해화율 99% 이상을 달성하였다. LCD televisions and monitors use cold cathode fluorescence lamps (CCFLs) to illuminate the screen. Most CCFLs contain mercury and they have to be carefully handled at the end of their lives as per minimum treatment standards under the Waste Electrical and Electronic Equipment (WEEE) and Restriction of Hazardous Substances (RoHS) directives. CCFLs were carefully separated from mold frames of waste LCD units for primary decontamination of mercury/fluorescent compound mixture using CCFL decontamination system designed and fabricated in the present research. Residual mercury was further removed by employing a pyro-process, where crushed CCFL tubes transferred from primary decontamination process were subject to heat treatment at <TEX>$550^{\circ}C$</TEX> in a box furnace: more than 99% of mercury was removable from waste CCFLs.

New Sn–0.7Cu-based solder alloys with minor alloying additions of Pd, Cr and Ca

The exemption clause for Pb-containing automobile parts in the RoHS (Restriction of Hazardous Substances) legislation will expire in a few years. Therefore, there is an urgent need to develop new Pb-free solder alloys that are suitable for automobiles. To improve the properties of the Pb-free solders used in automobiles that are consistently exposed to high temperatures and vibrations, we investigated the effects of minor alloying additions of chromium, calcium and palladium and examined the various properties of the resulting Sn–0.7Cu solders. We then investigated the new intermetallic compounds observed after the addition of chromium. In addition, we conducted thermal analysis to confirm the stability of the alloys at temperatures of approximately 230°C. The wettability and interfacial reactions between the solder alloys and the Cu under bump metallurgy are discussed. Furthermore, to evaluate the mechanical properties of the developed solder alloys, tensile tests were conducted. We confirmed that our minor alloying strategy enhances the strength and hardness of solder alloys without decreasing their melting temperatures.

Development of a large cooling capacity single stage GM cryocooler

Sumitomo Heavy Industries, Ltd. (SHI) has developed 4K Gifford–McMahon (GM) cryocoolers for various cryogenic fields including Magnetic resonance imaging (MRI) systems. However, for the purpose of cooling high temperature superconductor (HTS) devices, the needs for cryocoolers with a large cooling capacity in the range of 20–30K has been rapidly increasing.Recently, SHI developed a large cooling capacity single-stage GM cryocooler, for HTS applications. A typical cooling capacity is 46/52W at 20K or 85/96W at 30K with 6.9/7.9kW input power at 50/60Hz. The cooling capacity degradation caused by inclination is within 24%.And also, a low mechanical vibration and a low acoustic noise have been achieved because the displacer is driven by a motor instead of a pneumatic force. In addition, the cryocooler does not contain lead as a regenerator material, so it complies with restriction of hazardous substances (RoHS) directive.

Decontamination of Mercury contained in CCFLs (Cold Cathode Fluorescence Light) disassembled from Waste LCDs (Liquid Crystal Display)

LCD televisions and monitors use cold cathode fluorescence lamps (CCFLs) to illuminate the screen. Most CCFLs contain mercury and they have to be carefully handled at the end of their lives as per minimum treatment standards under the Waste Electrical and Electronic Equipment (WEEE) and Restriction of Hazardous Substances (RoHS) directives. CCFLs were carefully separated from mold frames of waste LCD units for primary decontamination of mercury/fluorescent compound mixture using CCFL decontamination system designed and fabricated in the present research. Residual mercury was further removed by employing a pyro-process, where crushed CCFL tubes transferred from primary decontamination process were subject to heat treatment at 550 o C in a box furnace: more than 99% of mercury was removable from waste CCFLs.

Comparison of Lead and WC-Co Materials against Gamma Irradiation

According to RoHS (Restriction of Hazardous Substances) directive of European Union it is restricted using lead in many equipment and applications. It is possible to enlarge the restriction of lead usage in some other applications which is including some of nuclear applications in the future. Therefore new materials or systems need to be developed instead of lead as radiation shielding materials and/or collimators. In this study pure tungsten, tungsten carbide-cobalt (WC Co) materials were investigated against gamma radiation. For gamma radiation Cs-137 and Co-60 gamma radioisotope sources were used. The linear and mass attenuations were calculated. The experimental results were compared with XCOM computer code. Usage possibilities of WC Co instead of lead in nuclear applications as gamma shielding material were discussed. It has been investigated that the linear gamma attenuation coe cients of lead and WC Co are very close to each other. Therefore it could be said that WC Co materials is an alternative promising material which could be used instead of lead as gamma shielding material and/or collimator.

Investigation on the Morphology of Sintered Silver Nanomaterial for Electronic Packaging Application

Silver nanoparticles are seen as a possible replacement for high temperature solders containing 90-95 wt.% Pb, which is widely used in various applications e.g. automotives. These high temperature solders have been exempted from the Restriction of Hazardous Substances (RoHS) Directive due to very limited drop-in replacement for the high temperature solders. Although the effect of sintering temperature of silver nanoparticles has been studied, the mechanism involved in the changes in the morphology of the particles and interfacial reaction with the substrate as a function of sintering temperature must be understood. In this study the effect of sintering temperature on the morpohology of Ag nanoparticles is discussed. The Scanning Electron Microscopy (SEM) analysis was used to analyze the changes in morphology of silver particles agglomerates with sintering temperatures. Results showed necking of the nanosilver powder, which indicated the occurrence of sintering through grain boundary diffusion process. Meanwhile, the micro-silver powder showed agglomeration of particles but no necking was observed. The study has shown that the Ag agglomerates was observed to undergo various changes to the particle morphology with different sintering temperatures.

An initial study on managing sustainability schools in Taiwan

Issues of environmental protection and greening our Earth have been increasingly talked about in all sectors of society. European industry standards such as WEEE (Waste Electrical and Electronic Equipment) and RoHS (Restriction of Hazardous Substances) have provided policies that forces organizations to become green. In the United States, sustainability policies are also being used to evaluate the institutions’ commitment towards environmental protection. In Taiwan, sustainability and green policies is not only limited to the industries, but also institutions of learning. In light of these issues, the current study shall focus on how sustainable are Taiwan higher education institutions. Using the Sustainability Tracking, Assessment and Rating System (STAR) framework of the Association for the Advancement of Sustainability in Higher Education (AASHE) of the US as a starting point, a survey questionnaire shall be administered to all higher education institutions all over Taiwan. Result shows that higher education institutions in Taiwan are engaging in sustainability strategies in all levels and functions of the organizations. Furthermore, the results are expected to fill the gap of extant literature with the in-depth investigation of the potential impact of the higher educational school on green practice and environmental performance in Taiwan.

English

In response to increasing worldwide awareness of the importance of business sustainability, there have been more and more environmental regulations enforced in the last decade for example, waste electrical and electronic equipment (WEEE)” and the “restriction of hazardous substances (RoHS). Those regulations have enormous impact on global supply chain systems and have begun to force companies to implement green supply chain management (GSCM). More specifically, firms must collaborate with their supply chain partners to improve their environmental management. This study examines the moderating effects of total quality environmental management (TQEM) on the relationship between GSCM and environmental performance (EP). The research premise is that total organizational effort from top management and employees facilitate the implementation of GSCM, which ultimately enhances green performance. The statistical results indicate that the interactions of GSCM and TQEM enhance environmental performance. Specifically, firms that implement GSCM practices and simultaneously adopt TQEM perform better in all aspects of environmental management. Several managerial implications are presented with suggestions for future research. Key words: Green supply chain management, environmental management, total quality environmental management.

Recycling of Waste Toner in the Republic of Croatia – an Environmentally Friendly Approach

Large amounts of waste toner cartridges have been generated as a consequence of their use in printers and duplicators on an everyday basis. Waste toner cartridges contain heavy metals, plastics, as well as toxic residual toner powder, and have been characterized as hazardous waste. Therefore the management of waste toner cartridge content presents a significant issue in environmental protection. The use of hazardous substances in electrical and electronic equipment, as well as promoting the collection, recycling and recovery targets for all types of electrical goods was prescribed by EU legislation, particularly the WEEE Directive and, together with the RoHS Directive, has been in force since February 2003. In order to concur with the WEEE Directive, a system for the management of electrical and electronic waste has been established in the Republic of Croatia five years ago, but there was no practical possibility for the treatment of collected waste toner cartridges. In this work, a study of the possibility of waste toner cartridges and further recycling and reuse has been performed, with special emphasis on the reuse of the residual toner powder. In order to decrease explosive properties of the residual toner powder, the material was mixed with calcite. After performed analyses of the mixture it was found that the mixture cannot be disposed of on landfill sites as inert waste material, since the value of the total organic carbon content (TOC) has found to be above the limit prescribed by the law. All other analyzed parameters have found to be below the limits prescribed by the law. Moreover, it was found that the mixture of residual toner powder, which contains 10 % of calcite, is an excellent bitumen additive, since it improves its application properties. So, the mixture of the residual toner powder and calcite can be used as a valuable raw material in the production of bituminous products and in different construction works.

Cross-Border Impacts of the Restriction of Hazardous Substances: A Perspective Based on Japanese Solders

Despite the relevance of the global economy, Regulatory Impact Assessments of the restriction of hazardous substances (RoHS) in the European Union (EU) are based only on domestic impacts. This paper explores the cross-border environmental impacts of the RoHS by focusing on the shifts to lead-free solders in Japan, which exports many electronics to the EU. The regulatory impacts are quantified by integrating a material flow analysis for metals constituting a solder with a scenario analysis with and without the RoHS. The results indicate that the EU regulation, the RoHS, has triggered shifts in Japan to lead-free solders, not only for electronics subject to this regulation, but for other products as well. We also find that the RoHS leads to a slow reduction in environmental emissions of the target, lead, but results in a rapid increase in the use of tin and silver in lead-free solders. This indicates the importance of assessing potential alternative substances, the use of which may increase as a result of adhering to the RoHS. The latter constitutes a negative impact because of recent concerns regarding resource criticality.

Essential updates on RoHS and REACH; an Electronics Yorkshire (EY) Seminar

Essential updates on RoHS and REACH; an Electronics Yorkshire (EY) Seminar

Qualitative and quantitative determination of heavy metals in waste cellular phones

Twenty four waste cellular phones, manufactured between 2002 and 2011, were selected in order to determine the total heavy metal content in each of their parts (printed circuit boards (PCBs), plastic housing (PH) and liquid crystal display monitors (LCDs)) and compare the results with the permissible limits set by the 2003 Directive on Restriction of Hazardous Substances (RoHS). All the selected samples were pulverized and digested with strong acids. Inductively coupled plasma-mass spectrometry was used to measure the heavy metal content in each sample. The results revealed that concentration levels of the examined heavy metals were higher in PCBs, followed by PH and LCD in that particular order (PCB>PH>LCD). With the exception of Pb and Cr present in PCBs of mobile phones released before the year 2006, all the other metal concentrations were according to the Directive. Concentration levels of Cd, Hg were lower than the permissible limits set by the EU, either before or after the validity of the 2003 RoHS Directive. Considering their significant heavy metal content, coupled with their large quantities produced worldwide in an annual rate, waste cellular phones need to be treated under an environmentally sound management scheme, prioritizing recycling and at the same time eliminating the possibility of any harm.

The Role of Pb Impurity in SAC Solder Alloy

The European Union and Japan initiated the issue of RoHS, the directive about the restriction of hazardous substances, which prohibits certain hazardous substances in electronic equipment - including lead - application. Due to the directive the use of lead free solder alloys is spreaded, however the Pb in the form of contamination may be appear under technological process. The lead impurity has significant effect on microstrucutre and lifetime so it is necessary to carry out detailed examinations. In this paper the study of intermetallic compounds in six-element, Pb impured, thermal cycles test-subjected, Sn-Ag-Cu (SAC) solder alloy is demonstrated

The replacement of research reactors with a compact proton linac for neutron radiography

The work presented here examines a neutron radiography facility, based on accelerator-driven compact neutron source, in order to find a suitable replacement for the facilities, which is based on research nuclear reactors. High-quality neutrons beam can be produced via the 9Be(p,n)9B reaction at proton energies of about 4MeV. Except for the Be target the materials considered were compatible with the European Union Directive on ‘Restriction of Hazardous Substances’ (RoHS) 2002/95/EC. According to this directive some common materials in radiography units such as lead and cadmium have been excluded. The suggested facility has been simulated with an extensive range of parameters, which characterizes the neutron radiography, and the results specify that an accelerator-based neutron source is an attractive alternative to research nuclear reactors.

Arsenic and antimony determination in non- and biodegradable materials by hydride generation capacitively coupled plasma microtorch optical emission spectrometry

A sensitive method using a miniature analytical system with a capacitively coupled plasma microtorch (25W, 13.56MHz, 0.4lmin−1 Ar) was developed and evaluated for the determination of As and Sb in recyclable plastics and biodegradable materials by hydride generation optical emission spectrometry. Given their toxicity, As and Sb should be subject to monitoring in such materials despite not being included within the scope of Restriction of Hazardous Substances Directive. The advantages of the proposed approach are better detection limits and lower analysis cost relative to conventional systems based on inductively coupled plasma optical emission and flame atomic absorption spectrometry with/without derivatization. Samples were subjected to acidic microwave-assisted digestion in a nitric–sulfuric acid mixture. Chemical hydride generation with 0.5% NaBH4 after the prereduction of As(V) and Sb(V) with 0.3% l-cysteine in 0.01moll−1 HCl (10min contact time at 90±5°C) was used. Under the optimal hydride generation conditions and analytical system operation the detection limits (mgkg−1) were 0.5 (As) and 0.1 (Sb), whereas the precision was 0.4–7.1% for 10.2–46.2mgkg−1 As and 0.4–3.2% for 7.1–156mgkg−1 Sb. Analysis of two polyethylene CRMs revealed recoveries of 101±2% As and 100±1% Sb.

Determination of chromium and antimony in polymers from electrical and electronic equipment using high-resolution continuum source graphite furnace atomic absorption spectrometry

In the last few years, the European Union adopted two directives: the Waste Electrical and Electronic Equipment (WEEE) directive and the Restriction of Hazardous Substances (RoHS) directive. The RoHS directive had a major impact on the routine control of hazardous substances, including toxic trace metals in all kind of materials that are used in electrical and electronic equipment. This work proposes an analytical method for the determination of Cr and Sb in polymers from different electrical and electronic equipment using direct analysis of solid samples and high-resolution continuum source graphite furnace atomic absorption spectrometry with calibration against aqueous standards. Additional strategies are presented for reducing the sensitivity in order to cope with high analyte concentrations. The limit of detection was found to be 0.06 mg kg−1 for both analytes, Cr and Sb, and the characteristic mass was 62 pg for Cr and 35 pg for Sb. The trueness of the method has been assessed by analyzing a certified reference material of low-density polyethylene, and a good agreement with the certified values has been obtained. The precision of the method, expressed as relative standard deviation (RSD), was between 4 and 13% for chromium and 4 and 10% for antimony. The method is sensitive, and fast, and it does not require any sample preparation except grinding.

Microstructure and Mechanical Properties of Directionally Solidified Unmodified and Ni-Modified Sn-0.7wt%Cu Lead-Free Solder Alloy

Lead containing solders (SnPb eutectic alloys) are widely used in electronic devices due to their good mechanical properties and low manufacturing cost. However, two European Union regulations (Waste from Electrical and Electronic Equipment and Restriction of Hazardous Substances) banned the use of lead in electrical and electronic equipment because of the toxic effect on human health and the environment. Nowadays, it is particularly important to find replacements for Pb containing solder materials. In that respect, copper is used as an alloying element and the composition Sn-0.7wt%Cu is of particular interest. Small Ni additions can be interesting since they would be included into the composition of the commercial solder SN100 and can also avoid the presence of coarse and deleterious Cu6Sn5 particles for Sn-Cu alloys in the hypoeutectic range of compositions. In the present investigation, growth rate, cooling rate, interfacial heat transfer coefficient (hi), the scale of the microstructure and morphologies, ultimate tensile strength and elongation have been experimentally determined for Sn-0.7wt%Cu and Sn-0.7wt%Cu-0.1wt%Ni alloys solidified in a water-cooled vertical upward unidirectional solidification system. Further, interrelations of thermal parameters, microstructure and tensile properties may be established. A higher time-dependent hi profile was found for the Sn-0.7wt%Cu-0.1wt%Ni alloy which seems to indicate that a higher fluidity was obtained with small Ni addition. Higher fluidity values may characterize better physicochemical affinity between the melt and the mould surface. The modified Sn-Cu alloy propitiates higher ultimate tensile strength values to be obtained. This may be due to the prevalence of eutectic two-phase cells along the casting associated with fine Cu-rich particles close to the water-cooled surface.

Efficient total analyses for bromine type flame retardants by simple NICI-GC/MS

We studied an efficient analytical method for detecting brominated aromatic compounds using negative ion chemical ionization (NICI), with well-known quadruple gas-chromatography mass-spectrometry (GC/MS). We utilized 79 and 35 m/z as monitoring ions of brominated compounds and syringe-spiked PCB#209, thus highly selective and sensitive detection was achieved. With 7.0 m long HP-5 GC column, decabromo-diphenyl ether (DBDE), hexabromobenzene, α-hexabromo cyclododecane (α-HBCD), and tetrabromo bisphenol A were utilized as bromine type flame retardants that are generally consumed in industrial commodities. A shorter column provided more efficient results without degradation of DBDE on GC which are usually observed with longer column (30 m). Also, pseudo environmental water samples can be analyzed without authentic pretreatment procedures. Furthermore, we demonstrated analyses for members regulated by the Restriction of Hazardous Substances. Consequently, the newly developed simple NICI-GC/MS method was effectively worked for screening of flame retardants in a short period of time.