High-entropy alloys (HEAs) have been reported to have better properties than conventional materials; however, they are more expensive due to the high cost of their main components. Therefore, research is needed to reduce manufacturing costs. In this study, CoCrFeMnNi HEAs were prepared using metal injection molding (MIM), which is a powder metallurgy process that involves less material waste than machining process. Although the MIM-processed samples were in the face-centered cubic (FCC) phase, porosity remained after sintering at 1200°C, 1250°C, and 1275°C. In this study, the hot isostatic pressing (HIP) process, which considers both temperature (1150°C) and pressure (150 MPa), was adopted to improve the quality of the MIM samples. Although the hardness of the HIP-treated samples decreased slightly and the Mn composition was significantly reduced, the process effectively eliminated many pores that remained after the 1275°C MIM process. The HIP process can improve the quality of the alloy.

High-entropy alloys (HEAs) are attracting attention because of their excellent properties and functions; however, they are relatively expensive compared with commercial alloys. Therefore, various efforts have been made to reduce the cost of raw materials. In this study, MIM is attempted using coarse equiatomic CoCrFeMnNi HEA powders. The mixing ratio (powder:binder) for HEA feedstock preparation is explored using torque rheometer. The block-shaped green parts are fabricated through a metal injection molding process using feedstock. The thermal debinding conditions are explored by thermogravimetric analysis, and solvent and thermal debinding are performed. It is densified under various sintering conditions considering the melting point of the HEA. The final product, which contains a small amount of non-FCC phase, is manufactured at a sintering temperature of 1250oC.

In this study, copper vapor chambers with built-in cooling fins, which eliminated the soldered or brazed joints in the conventional vapor chamber, were fabricated using the metal injection molding process. The results show that with optimized molding parameters, fins with an aspect ratio up to 18 could be produced. After sintering, the densities of the fin and chamber reached 96%. With only 32 cooling fins and a small fan installed, the thermal resistance of the heat sink was 1.156 ℃/W, and the power dissipation was 40W when the junction temperature was 70℃. When copper powder was sintered onto the chamber to make a vapor chamber, the thermal resistance decreased to 1.046℃/W.

Mo2FeB2 boride base cermets produced by a novel sintering technique, called reaction boronizing sintering through a liquid phase, have excellent mechanical properties and wear and corrosion-resistances. Hence, the cermets are applied to the injection molding die-casting machine parts and so on. We investigated that the effect of deoxidization and sintering temperature on mechanical properties and deformation of the MIM processed cermets. As a result, deoxidization temperature of 1323K and sintering temperature of 1518K were suitable. The MIM products of the cermets showed allowable dimensional accuracy and the same mechanical properties as the presssintered ones.

Gas surface treatment is considered to be effective for titanium because of its high reactivity. In this study, we investigated the gas nitriding mechanism in titanium sintered parts produced by metal powder injection molding (MIM) process. The microstructure and nitrogen content of sintered MIM parts were greatly affected by nitriding conditions. Nitriding process strongly depended on the specimen size, for example, the size of micro metal injection molding (μ-MIM) product is so small and the specific surface is so large that the mechanical and functional properties can be modified by nitriding.

Mechanical properties of metal injection molded titanium and titanium alloy parts were investigated in this study. Material powders with low oxygen content and spherical shape were obtained by electrode induction-melting gas atomization which could melt and atomize titanium and titanium alloy bars with no touch on crucible or tundish. Tensile specimens were fabricated from obtained powders by metal injection molding process. Tensile strength of the specimens increases with increasing oxygen content. This result corresponds to a tendency of wrought metal.

In this paper, rheological characteristics of Metal Injection Moulding (MIM) feedstock using locally binder of palm stearin are presented. The feedstock consisted of 316L-grade stainless steel powder with three different particle sizes and the binders comprise palm stearin and polyethylene. The viscosity of MIM feedstock at different temperatures and shear rates was measured and evaluated. Results showed that, the feedstock containing palm stearin exhibited suitable rheological properties and suitable to produce a homogeneous feedstock that is favorable for injection molding process.

This paper describes a Plasma Assisted Debinding and Sintering (PADS) equipment, which has been designed to process Metal Injection Molded (MIM) components. The use of a hybrid system combining a glow discharge with a conventional heating system makes debinding and sintering of MIM components, in the same heating cycle, a feasible industrial process. Characteristics as density, carbon content and mechanical properties are similar to traditionally processed MIM materials. The reduction of energy and gas consumption and shorter lead-times are economic advantages of PADS system. The clean environment of PADS is also an ecological advantage.

Production components fabricated by metal powder injection molding are analyzed for features to identify the design window for this powder technology. This reverse approach lets the designer see where PIM has a high probability to succeed. The findings show that the most suitable components tend to be less than 25 mm in size and less than 10 g in mass, are slender, and have high complexity.

A novel production method for porous metal components has been developed by applying powder space holder (PSH) method to metal powder injection molding (MIM) process. The PSH-MIM method has an industrial competitive advantage that is capable of net-shape manufacturing the micro-sized porous metal products with complicated shapes and controlled porosity and pore size. In this study, the small impeller with homogeneous micro-porous structure was manufactured by the PSH-MIM method. The effects of combinations in size and fraction of PMMA particle on dimensional tolerance and variation of sintered porous specimens were investigated. It was concluded that the PSH-MIM method could manufacture commercially microporous metal components with high dimensional accuracy.

The production method of micro sacrificial plastic mold insert metal injection molding, namely process has been proposed to solve specific problems involving the miniaturization of MIM. Two types of sacrificial plastic molds (SP-mold) with fine structures were used: 1) PMMA resist, 2) PMMA mold injected into Ni-electroform, which is a typical LIGA () process. Stainless steel 316L feedstock was injection-molded into the SP-molds with multi-pillar structures. This study focused on the effects of metal particle size and processing conditions on the shrinkage, transcription and surface roughness of sintered parts.

This study aims to investigate the usage of nano-scale particles in a micro metal injection molding (-MIM) process. Nanoscale particle is effective to improve transcription and surface roughness in small structure. Moreover, the effects of hybrid micro/nano particles, Cu/Cu and SUS/Cu were investigated. Small dumbbell specimens were produced using various feedstocks prepared by changing binder content and fraction of nano-scale Cu particle (0.3 and in particle size). The effects of adding the fraction of nano-scale Cu powder on the melt viscosity of the feedstock, microstructure, density and tensile strength of sintered parts were discussed.

통상적인 금속분말의 성형은 분말야금 공정으로 이루어지기 때문에 복잡한 형상의 부품을 구현하는 데는 제약이 있다. 하지만, 1970년대 후반 이래 새로운 금속분말의 성형기술로 크게 각광을 받으며 연구되고 있는 금속분말사출성형(Metal Powder Injection Molding, MIM) 기술을 이용하면 다양한 형태의 부품을 성형할 수 있다 최근에는 이러한 MIM 기술을 이용하여 다양한 산업분야에 응용될 수 있는 마이크로 부품을 제조하고자 하는 연구개발

The purpose of the present study is to investigate the method decreasing debinding time as well as lowering operation condition than pure supercritical debinding by using cosolvent or binary mixture of propane + . First method is to add cosolvent, such as n-hexane, DCM, methanol, 1-butanol, in supercritical . In case of adding cosolvent, we were found the addition of non-polar cosolvent (n-hexane) improves dramatically the binder removal rate (more than 2 times) compared with pure supercritical debinding, second method is to use mixture of supercritical propane + , as solvent. In case of using mixture of supercritical propane + , the rate of debinding speeded up with increasing of pressure and concentration of propane at 348.15 K. It was found that addition of cosolvent (e.g., n-hexane, DCM) and binary mixture propane + for supercritical solvent remarkably improved binder removal rate for the paraffin wax-based binder system, in comparison with using pure supercritical .

The production of micro components is one of the leading technologies in the fields of information and communiation, medical and biotechnology, and micro sensor and micro actuator system. Microfabrication (micromachining) techniques such as X-ray lithography, electroforming, micromolding and excimer laser ablation are used for the production of micro components out of silicon, polymer and a limited number of pure metals or binary alloys. However, since the first development of microfabrication technologies there have been demands for the cost-effective replication in large scale series as well as the extended range of available material. One such promising process is micro powder injection molding (PIM), which inherits the advantages of the conventional PIM technology, such as low production cost, shape complexity, applicability to many materials, applicability to many materials, and good tolerance. This paper reports on a fundamental investigation of the application of W-Cu powder to micro metal injection molding (MIM), especially in view of achieving a good filling and a safe removal of a micro mold conducted in the experiment. It is absolutely legitimate and meaningful, at the present state of the technique, to continue developing the micro MIM towards production processes for micro components.

Recent remarkable progress in the semiconductor industry has promoted smaller size of semiconductor chips and increased amounts of heat generation. So, the demand for a substrate material to meet both the characteristics of thermal expansion coefficient and heat radiation has been on the increase. Under such conditions, tungsten(W)-copper(Cu) has been proposed as materials to meet both of the above characteristics. In the present study, the W-10wt.%Cu powders were synthesised by the mixing and hydrogen reduction of the starting mixture materials such as W-Cu, and in order to obtain the full densification. The W-10wt.%Cu produced by hydrogen reduction showed the higher interparticle friction than the simple mixed W-10wt%Cu because of the W agglomerates. In the dilatometric analysis the W-10wt.%Cu prepared from the was largely shrank by heating up at the constant heating rate of /min. The possibility of application of metal injection molding (MIM) was also investigated for mass production of the complex shaped W-Cu parts in semiconductor devices. The relationship between the temperature of molding die and the pressure of injection molding was analyzed and the heating up stage of 120- in the debinding process was controlled for the most suitable MIM condition.