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The steel powders were sintered under N 2 –H 2 atmosphere in a solar furnace and in a Fresnel lens, after compaction of the green parts, using much higher heating and/or cooling rates as compared to conventional tubular furnace. The effects of processing parameters and the use of concentrated solar energy on densification and mechanical properties were analyzed. Experimental results demonstrated the activating effect of concentrated solar energy on the sintering process showing that an optimum densification is achieved at 1150 °C on both solar installations in just 90 min for the solar furnace and in 30 min in the case of Fresnel lens installation compared with an optimum temperature of 1290 °C in ∼10 h of total cycle in the conventional tubular furnace. Better mechanical properties were obtained using concentrated solar energy with microhardness measurements ranging between 800 and 900 HV. Microstructural analyses by scanning and transmission electron microscopy reveal the presence of submicron sized vanadium nitrides and other nanometer sized particles in the samples that could be responsible for the high hardness values obtained.

In this communication, we present the powder injection moulding (PIM) of HS12-1-5-5 high-speed steel parts using a wax-HDPE based binder. The injection moulding process of the feedstock (68 vol.% of metal) has been optimized to obtain high quality green parts. The elimination of organic binder was carried out by thermal debinding under inert atmosphere. In order to keep carbon in the sample that could improve the sintering process, incomplete debinding were performed between 450 and 500 °C. In this study, we have studied the effect of different atmospheres on the debinding process. Debinding was performed under nitrogen and argon. The specimens were sintered at temperatures between 1200 and 1300 °C with steps of 10 °C in following mixture N 2 –10% H 2 atmosphere. The PIM parts present higher density than those obtained by conventional PM.