The machinability of powder metallurgy materials is considered to be poor. The main factors that deteriorate the machining of PM parts are introduced in this work. They are those which participate in different ranges and modes in the formation of a sintered body with required mechanical and other characteristics. The effect of base iron powders, alloying systems, and alloying elements, as well as the effect of processing routes, especially solid-state sintering, are mentioned. The characteristic heterogeneous microstructures are presented. The effect of porosity in terms of interrupted and deformation cutting theories is discussed and demonstrated. The main measures to improve machinability of PM materials are described.

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A B S T R A C TRemoval of nickel ions from aqueous solutions using modified ZSM-5 nanozeolites was investigated. Experiments were conducted in terms of different solute concentrations, temperatures, and pH. Mesoporous Na-ZSM-5 zeolite was modified with tetrapropylammonium bromide (TPABr) and sodium dodecylsulfate (SDS) by using the impregnation method. The modified zeolites were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, Brunauer-Emmett-Teller, and scanning electron microscope techniques. According to the results, SDS-ZSM-5 revealed a higher adsorption capacity than Na-ZSM-5 and TPA-ZSM-5. Langmuir and Freundlich adsorption models were used for the mathematical description of the adsorption equilibrium. The analyses revealed that the sorption of Ni(II) could be considered an endothermic and spontaneous process.

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