Kohmei Halada

Production of fine spherical lead-free solder powders by hybrid atomization

Considerable R&D efforts in last decade have identified several promising lead-free tin alloys for the replacement of lead-containing solders in microelectronic applications. However, it is difficult or uneconomical to produce high-quality solder balls industrially by means of conventional atomization methods. To produce acceptable lead-free solder balls efficiently and industrially, a novel powder-making process change to active voice. Hybrid Atomization that combines free fall gas atomization and centrifugal atomization effectively, was invented and developed recently by us. This new technique can produce very fine, spherical tin alloy powders with mean diameters of about 10 mm, very narrow size distributions, few satellites and low production costs. Taking Sn-9mass%Zn alloy as an example, process experiments were carried out and the optimal processing conditions obtained. Results show that the influences of processing parameters and optimum conditions are very different from those in conventional atomization processes. The spherical powder with a mean particle size of 10.6 mm and a standard deviation of 1.3—1.7 mm was obtained in the determined optimum condition.

Materials development for a sustainable society

Abstract The large consumption of materials and energy causes rapid deterioration of the environment on a global scale. The increase of aging plants, facilities and machines threatens our safety. Environment and safety are key issues which have to be considered for a sustainable society, when we think what the technology and systems of the 21st Century should be like. The guiding principles for materials development towards a sustainable society are discussed from the viewpoint of environment and safety.

Tensile behavior change depending on the microstructure of a Fe–Cu alloy produced from rapidly solidified powder

Abstract The relationship between consolidating temperature and the tensile behavior of iron alloy produced from Fe–Cu rapidly solidified powder is investigated. Fe–Cu powder fabricated by high-pressure water atomization was consolidated by heavy rolling at 873–1273 K. Microstructural changes were observed and tensile behavior was examined. Tensile behavior varies as the consolidating temperature changes, and these temperature-dependent differences depend on the morphology of the microstructure on the order of micrometers. The sample consolidated at 873 K shows a good strength/elongation balance because the powder microstructure and primary powder boundaries are maintained. The samples consolidated at the higher temperatures have a microstructure of recrystallized grains, and these recrystallized samples show the conventional relationship between tensile behavior and grain size in ordinal bulk materials.

Detection and recovery of palladium, gold and cobalt metals from the urban mine using novel sensors/adsorbents designated with nanoscale wagon- wheel-shaped pores

Developing low-cost, efficient processes for recovering and recycling palladium, gold and cobalt metals from urban mine remains a significant challenge in industrialized countries. Here, the development of optical mesosensors/adsorbents (MSAs) for efficient recognition and selective recovery of Pd(II), Au(III), and Co(II) from urban mine was achieved. A simple, general method for preparing MSAs based on using high-order mesoporous monolithic scaffolds was described. Hierarchical cubic Ia3d wagon-wheel-shaped MSAs were fabricated by anchoring chelating agents (colorants) into three-dimensional pores and micrometric particle surfaces of the mesoporous monolithic scaffolds. Findings show, for the first time, evidence of controlled optical recognition of Pd(II), Au(III), and Co(II) ions and a highly selective system for recovery of Pd(II) ions (up to ~95%) in ores and industrial wastes. Furthermore, the controlled assessment processes described herein involve evaluation of intrinsic properties (e.g., visual signal change, long-term stability, adsorption efficiency, extraordinary sensitivity, selectivity, and reusability); thus, expensive, sophisticated instruments are not required. Results show evidence that MSAs will attract worldwide attention as a promising technological means of recovering and recycling palladium, gold and cobaltmetals.

Ecomaterials in the Global Eco-Society: Present Situation and Future Prospects

The concept of environmental conscious materials, ecomaterials, is reviewed. It has dispersed and recognized in the world as contributing to a sustainable society. Advanced models for secondary materials utilization, environmental benign processes and new material recycling systems are introduced.

Forecasting the Consumption of Metals up to 2050

Forecasting are made regarding the consumption up to 2050 of following metals: Fe, Al, Cu, Mn, Zn, Cr, Pb, Ni, Si, Sn, rare earths, Mo, Li, Sb, W, Ag, Co, In, Au, Ga, Pt and Pd. The forecasts are based on the liniar decoupling model of the relation between per capita metal consumption and per capita GDP. The models of each metal are applied to the economic development model of BRICs and G6 countries. According these forecasts, the overall consumption of metals in 2050 will be five times greater than the current levels, and demand for metals, such as Au, Ag, Cu, Ni, Sn, Zn, Pb, and Sb, is expected to be several times greater than the amount of their respective reserves. Demand for iron and platinum, which is considered to be optimistic about the resource exhaustion, will also exceed the current reserves. Urgent measures are needed to find alternatives from common resources and to shift into materials circulation society.

Improvement in elongation of sintered Fe–Cu alloy by chemical reduction of the surface of rapidly solidified powder

Abstract The effect of oxide inclusions on the tensile properties of a Fe–Cu consolidated alloy was investigated. Fe–Cu powders with a copper content in the range of 0.5–5 mass% were prepared by high-pressure water atomization and reduced in a hydrogen atmosphere to remove surface oxides. The as-atomized and reduced powders were consolidated by groove rolling at 973 K. Microstructures were characterized by scanning electron microscopy and tensile properties were determined. The microstructure where recrystallized grains appeared was observed in the samples from both powders; there were fewer and smaller inclusions in the samples from the reduced powder. Reduction of the oxide inclusions contributed to increased elongation of the consolidated samples. Control of the inclusion at the powder surface is necessary in order to obtain plasticity.

Potential of Urban Mine

The potential of urban mining is getting greater. From the global view, the potential of urban mining, namely the estimated amount of on-surface stock which has been mine form the geo-sphere into the techno-sphere, is comparative to natural resource which is still in geo-sphere as underground stock. However, practical recycling of metals are still in the stage of developing, and depending on the country. As an example, ultimate potential of urban mine in Japan was estimated. The differences between input of each metal contents and output of it were considered to be accumulated. I/O method was combined to estimate the metal contents in exported products. Japan, which is considered a typical exporter of materials, has great potential of urban mining which comes from domestic demand of products. However, real activity of development of urban mine, namely recycling, is not so effective, especially for minor metals which sometime called rare metals from the viewpoint of the importance in industries. We need to develop the technology and system for urban mining, just now.

Application of 3-Dimensional Powder Laminating Fabrication to Metallic Components

Production of dense metal products by a three-dimensional inkjet printing system was developed. Carbonyl nickel powder with a mean particle size of 5μm was used as a raw material and two binder supply methods, (i) coating a water soluble polymer on the powder and then supplying thin polymer-dissolved water from the inkjet head; (ii) supplying a binder directly from the inkjet head were examined. The layered green product was sintered in a hydrogen atmosphere at a temperature in the range of 1073-1623K. Microstructure observation was done and sintering procedure was discussed. Sintered samples fabricated from the coated powder had non-uniform microstructure with different densities due to agglomeration of the coated powder. The inhomogeneous microstructure was improved by screening the agglomerated particles, or agglomerating most of the powder to the contrary. However, the elimination of the density variegation was not achieved in the method using the coated powder. In samples made from the powder bonded by the binder directly, microstructure was fairly homogeneous. The homogeneous microstructure helped uniform sintering, and the macroscopic shape was retained after high temperature sintering at 1623K, and a high density of over 90% was achieved.

Growth of Ecomaterials and Eco-efficiency in Major Metallic Structural Materials

The concept of environmentally conscious materials, ecomaterials, is historically reviewed through the activity of ecomaterials forum in Japan from 1992. The ecomaterials can be defined as those materials designed by environmental lifeO. Umezawa (*) Faculty of Engineering, Yokohama National University, Yokohama, Kanagawa, Japan e-mail: umezawa-osamu-fv@ynu.ac.jp Y. Shinohara National Institute for Materials Science, Tsukuba, Ibaraki, Japan K. Halada National Institute for Materials Science, Tsukuba, Japan # Springer Nature Switzerland AG 2019 L. M. T. Martínez et al. (eds.), Handbook of Ecomaterials, https://doi.org/10.1007/978-3-319-68255-6_13 2261 cycle engineering and that are superior to conventional materials in terms of lifecycle assessment or analysis (LCA). In particular, the ecomaterials are associated with minimal health hazards, minimal harmful emissions and wastes, minimal energy requirement, maximal recyclability and minimal material resource depletion, optimal physical properties, and best technical performance. From the viewpoints of high eco-efficiency of products, novel processes in major metallic structural materials like steel and aluminum are introduced. Electric arc furnace (EAF) steelmaking has an advantage of low environmental load, since it produces steels and their parts from steel scrap. The thin slab casting (TSC)-EAF has producedflat-rolled steels in mini-mill steelworks. Materials flow and benign manufacturing are focused as a part of activities in ecomaterials. The new categorization of ecomaterials is also described where advanced steps ranging from high eco-efficiency of products to consumer-oriented and regional community adaptation are introduced. Ecomaterials with Social Systems Presently, materials security and production of environmentally conscious materials (ecomaterials) [5] are of concern to the global community, which needs to recognize the challenges that both present. As a nation, Japan has focused on better management of natural resources and materials and has developed a framework to advance a move towards a closed-loop economy through advancing and implementation of its knowledge of the 3Rs (reduce, reuse, recycle). Ecomaterials also make an important role in eco-design, where it is an approach to design a product with special consideration for the environmental impacts of the product during its whole life cycle. Substantial progress has been made in eco-design and high-performance fabrication for sectors such as living, automotive, electrical, machinery, and building, where a need to improve resource productivity and adopt ecomaterials is a key priority for progress [20]. In Europe, a circular economy [23] is a regenerative system in which resource input and waste, emission, and energy leakage are minimized by slowing, closing, and narrowing material and energy loops. This can be achieved through long-lasting design, maintenance, repair, reuse, remanufacturing, refurbishing, and recycling. Underpinned by a transition to renewable energy sources, the circular model builds economic, natural, and social capital. Concept of Ecomaterials The concept of ecomaterials, defined as an ecosphere with three basic paths (i.e., frontier, environmental protection, and amenity), was originally proposed in Japan in 1992 and became the preferred area of focus in materials engineering through the 1990s [5]. The ecomaterials developed under three phases take a holistic view of the ecosphere and progress along three basic paths as shown in Fig. 1. The basic paths are defined as follows: 2262 O. Umezawa et al.