The influence of powder characteristics on the sintering behaviour and impurity content of spark-plasma-sintered zirconium

The Extrusion and SPS of Zirconium–Copper Powders and Studies of Selected Mechanical Properties

“…Despite temperature control, an explosive reaction could occur during mixing, and there was a risk of damaging the bowl. In one of our experiments at a speed of 400 rpm, an uncontrolled explosion occurred due to the large absorption of gases inside the container (hydrogen, oxygen and nitrogen, which were detected in the study of powder contamination in one of our publications [5]), and after this incident, we gave up from the high-speed mixing of mixtures containing zirconium powder. The conditions for the preparation of mixtures with zirconium were developed in the research presented in [24].…”

“…In Table 2, the influence of the temperature of the SPS process on the relative densities and hardness of Zr-Cu materials is presented. The sintering time of the material of 60 s was determined on the basis of minimizing grain growth during the sintering of zircon without additives [5]. The basic criterion for selecting the sintering temperature was the melting point of copper-1083 °C.…”

“…In Table 2, the influence of the temperature of the SPS process on the relative densities and hardness of Zr-Cu materials is presented. The sintering time of the material of 60 s was determined on the basis of minimizing grain growth during the sintering of zircon without additives [5]. The basic criterion for selecting the sintering temperature was the melting point of copper-1083 • C. However, during sintering by the SPS method, which is based on electric discharges between the particles of the sintered material, a much higher temperature may occur at the point of connection of the particles, which often leads to the appearance of a liquid phase at temperatures of at least 100 • C lower than the melting point of the sintered metal, in this case, copper.…”

“…The HDH method is used most often; however, zirconium powders have an irregular shape [1]. Contamination of zirconium powders by air (more specifically oxygen) and hydrogen is thus a problem during sintering [5]. This contamination causes an increase in tensile strength and hardness but reduces ductility, resulting in crack formation.…”

Powder Bed Fusion Additive Manufacturing Using Critical Raw Materials: A Review

“…New technologies such as direct laser sintering and microwave sintering, used to manufacture high-quality components, require spherical powders with narrow particle size distribution as this affects the packing density and sintering mechanism [ 90 ]. Zr, especially in the state of powder, has a very strong activity and strong chemical affinity for oxygen, nitrogen, and hydrogen, so it must be prepared, handled, and processed in tightly controlled technological conditions such as high vacuum and an atmosphere of extra-pure inert gas [ 91 ]. Nevertheless, the progress of gas atomization methods already allows for the manufacturing of complex AM-grade powders such as highly biocompatible HEA TiNbTaZrMo ones [ 92 , 93 ].…”