Reproductive techniques like injection molding or embossing of feedstock provide microstructures of a wide variety of materials for a reasonable price to micro system technology. In this paper, the dependencies and barriers to produce high aspect ratio structures by micro metal injection molding are described; some results of embossing of metal powder based feedstocks are presented, too. The investigations show different influencing parameters for reaching high aspects ratios. The main factor is the used powder, finer powders allow higher aspect ratios. Moreover, the binder system, the feedstock (mixture of powder and binder) and the quality of the injection mold influence the reproduction process

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Micro system technology (MST) needs cost effective production techniques and for the development of new MST products new materials are necessary. Reproduction technologies have been developed for large scale production which allow processing of a broad scope of materials (plastic, ceramic and metal). For these, tools are needed which have to fulfil a lot of requirements. In this paper the results of an evaluation of micro powder metallurgy (MPM) as a technology to produce highly productive tools and moulds for structuring of plastics and metals by reproduction, possibly also for difficult materials such as glass, are presented. Moulds made of iron, stainless steel and hard metal of different designs were produced and quality issues investigated. Results of hot embossing and injection moulding of metal and plastic using these inserts produced by micro powder metallurgy are given

A pressureless sintering method was utilized to fabricate metal/ceramic joints out of yttria‐stabilized zirconia (3Y‐TZP) and stainless steels (SS). Ultrafine (150 nm) and nanoscale (75 nm) 3Y‐TZP particles and micrometric 17‐4PH, 316L, and 420 SS (<31 μm) powders were tested. Isothermal and nonisothermal sintering behaviors of the powders and composite layers in hydrogen, argon, and vacuum atmospheres were examined. It was found that the mismatch strain between the zirconia ceramic and SS during cosintering is significant, which leads to bond cracking and joint failure. Nevertheless, interlayer diffusion of Zr, Fe, and Cr and the formation of a reaction zone, particularly during vacuum sintering, enables an accommodation of the residual stresses caused by the mismatch shrinkage upon cooling. The formation of a porous region close to the metal layer was observed. Sinter joining of zirconia to 420 SS is more successful compared with austenitic steel because of a lower difference in the coefficient of thermal expansion.

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Researchers in Germany and Iran have looked at methods of manufacturing wear parts using nanostructured hardmetal combined with a cheaper stainless steel component in pursuit of cost effectiveness. Nanostructured WC-10%Co-0.9%VC and 316L SS powders were used as starting materials. A polymer-wax binder composed of polyethylene copolymer-ethylene vinyl acetate, carnauba wax, paraffin and stearic acid was used to prepare the hardmetal feedstock in a laboratory kneader with z-mixing blades at a temperature of 120°C. The assembled PIM parts were sintered in a laboratory sintering furnace under nitrogen according to different sintering cycles in the temperature range of 1320-1360°C with a heating rate of 10-20 K/min. The density of the sintered samples was measured by the water displacement method. The team found that reactions occur between the hardmetal and stainless steel at high temperatures, which eventually distort the shape of PIM parts due to excess melt formation eve n at temperatures as low as 1250°C

Abstract. Due to the increased and unstable prices for Rare Earth elements there are activities to develop alternative hard magnetic materials. Reducing the amount of material necessary to produce complex sintered NdFeB magnets can also help to reduce some of the supply problem. Metal Injection Molding (MIM) is able to produce near net shape parts and can reduce the amount of finishing to achieve final geometry. Although MIM of NdFeB has been patented and published fairly soon after the development of the NdFeB magnets there has never been an industrial production. This could be due to the fact that MIM was very young at that time and hardly developed. Thus, the feasibility of the process needs to be revaluated. This paper presents results of our work on determining the process parameters influencing the magnetic properties of the sintered magnets as well as the shrinkage during processing. The role of binder and powder loading on the alignment of the particles as well as on the carbon and oxygen contamination was examined.