JOM最新文献

AISI 1045 steel is widely used in mechanical parts of industrial equipment. However, its surface mechanical properties can be improved to increase this steel's applicability and service life. This study proposes an evaluation of the feasibility of duplex treatment concerning plasma nitriding (PN) and cathodic cage plasma deposition (CCPD) for reducing wear on AISI 1045 steel. X-ray diffraction, roughness, Vickers hardness, scanning electron microscopy, and wear test results showed that duplex treatment (PN + CCPD) caused the formation of nitride phases responsible for surface hardening, a significant increase in wear resistance for samples subjected to PN and duplex treatment. However, the sample subjected to duplex treatment showed a hardness 77.2% higher than that of the sample that was only nitrided and a greater depth of surface modification, giving the duplex treatment mechanical advantages due to the longer period of time required for AISI 1045 mechanical parts.

Additive manufacturing has been widely used in industries. The plasticity and fatigue behaviors of AlSi10Mg alloy parts manufactured by selective laser melting (SLM) are generally poor. Thus, this paper studies the microstructure and mechanical properties of SLM-manufactured AlSi10Mg alloy under aging, annealing, solution and T6 heat treatments. The results demonstrate that these heat treatments enhance the plasticity of the material, especially for the T6 treatment, which exhibits a plasticity 3.2 times greater than that of the as-deposited alloy. However, the tensile and yield strengths of the AlSi10Mg alloy decrease. The T6 treatment exhibits the highest fatigue life, which is five times higher than that of the as-deposited alloy. The microstructure of the annealing treatment consists of reticulated eutectic Si, while the aging treatment displays reticulated Si fractures and an increased presence of spherical Si particles. In contrast, the solution and T6 treatments exhibit blocky Si structures and micropores. The microstructural alteration of the silicon state after heat treatment is attributed to the enhanced fatigue life.

To explore the effects of laser processing variables on the macroscopic appearance, microstructural makeup, and functional properties of high-entropy alloy (HEA) coatings, CoCrFeNiMn coatings were deposited onto the surface of Q235 steel via laser cladding, with adjustments made to parameters like laser power and scanning speed. The research findings indicate that augmenting laser power leads to a concurrent increase in the coating's depth, width, and dilution rate. Conversely, when the scanning speed is escalated, there is a noticeable reduction in both the width and height of the coating. The coating predominantly consists of a single FCC phase structure; the microstructure is a typical organization of columnar and equiaxed crystals. The microhardness of the coating prepared under different parameters exceeds that of the substrate. Coatings prepared at 1.2 kW and 800 mm/min exhibit high hardness and exceptional wear resistance, with abrasive wear as the predominant wear mechanism.

It is difficult to depress secondary copper sulfide minerals in the separative flotation of copper–molybdenum coexisting ores with a huge NaHS consumption, and causing serious safety and environmental problems. Galvanic interaction between active metallic granular (low consumption depressant; LCD) and secondary copper sulfide mineral particles can induce surface passivation, thereby depressing its floatability and achieving clean and efficient regulation of copper molybdenum separation. The use of 10% LCD was applied at the first stage and 5 kg/t NaHS at the second stage can recover 89.71% of Cu, while only 52.89% of Cu can be recovered for single stage flotation where 20 kg/t NaHS was used without any presence of LCD. To avoid the negative effect of Mg(OH)₂ colloids at higher pH at the second stage, sodium hexametaphosphate (SHMP) was added as a dispersant and Mo recovery could be pulled up to 89.63%.

The chemical and process mineralogical characteristics of carbon-bearing lead–zinc ore in Sanguikou, Inner Mongolia, China, were investigated. The study aimed to identify the mineral characterizations and distribution of lead, zinc, and carbon. X-ray fluorescence and chemical analysis showed lead, zinc, and carbon grades of 0.58%, 2.44%, and 5.33%, respectively. X-ray diffraction, polarizing microscopy, and mineral liberation analysis revealed lead and zinc mainly occur as galena and marmatite, with carbon as graphite. The particle sizes are small and symbiotic relationships complex. Additionally, the characteristic features of carbon-bearing lead–zinc ore were summarized, and the current plant flowsheet and outcomes were assessed. The improved flowsheet includes X-ray sorting before grinding and a flotation column in zinc flotation to treat the regrinding middling separately. This approach achieved a Pb grade of 65.34% with a recovery of 70.64% and a Zn grade of 45.61% with a recovery of 89.98%. The Sanguikou plant processes 5000 t/day, producing 23.58 t of lead concentrate and 105.41 t of zinc concentrate daily. The new flowsheet enhances the grade and recovery of lead and zinc concentrates. The proposed flowsheet is a promising comprehensive recovery method and cleaner production process for this unique lead–zinc resource.