The preliminary stage of asphalt mixture production involves the drying and dedusting of coarse aggregates. The most common types of coarse aggregates used are limestone and basalt. In the process of drying and dedusting the dryer filter accumulates large quantities of waste in the form of mineral powder.

This paper introduces an investigation into limestone powder waste as a potential microfiller of polymer composites. Physical characteristics such as the granulation the of powder collected from the filter - in terms of the season of its collection and the type of input materials used - were analysed. A scanning electron microscope (SEM) was used for the investigation described within this paper. The obtained results were compared against those of other materials which can be used as polymer composites microfillers.

We discuss meal colors, food-drying secrets, and changing consumer demands with Dr. Anna Michalska from the PAS Institute of Animal Reproduction and Food Research in Olsztyn.

In this study, the effect of gas pressure on the shape and size of the AZ91 alloy powder produced by using the gas atomization method was investigated experimentally. Experiments were carried out at 820°C constant temperature in 2-mm nozzle diameter and by applying 4 different gas pressures (0.5, 1.5, 2.5 and 3.5 MPa). Argon gas was used to atomize the melt. Scanning electron microscope (SEM) to determine the shape of produced AZ91 powders, XRD, XRF and SEM-EDX analysis to determine the phases forming in the internal structures of the produced powders and the percentages of these phases and a laser measuring device for powder size analysis were used. Hardness tests were carried out to determine the mechanical properties of the produced powders. The general appearances of AZ91 alloy powders produced had general appearances of ligament, acicular, droplet, flake and spherical shape, but depending on the increase in gas pressure, the shape of the powders is seen to change mostly towards flake and spherical. It is determined that the finest powder was obtained at 820°C with 2 mm nozzle diameter at 3.5 MPa gas pressure and the powders had complex shapes in general.

The purpose of the study was to analyse the effect of changes in the composition of raw material and agglomeration on sorption properties of a multi-component food, in the example of a powdered cocoa beverage. The basic composition of the mixtures was 20% of cocoa and 80% of sucrose. A change in raw material composition involved partial or total replacement of sucrose with a mixture of glucose and fructose, or with maltodextrin. Analysis of sorption properties demonstrated variability in the course of isotherms of water vapour sorption for components of the powdered cocoa beverage. Limiting water activity (aw) was determined for the value of 0.529. The conducted analysis detected no significant effect of agglomeration on water content in the tested products. However, a significant change in the raw material composition was demonstrated.

In this study, an oxide reduction process and a reduction-sintering process were employed to synthesize a thermoelectric alloy from three thermoelectric composite oxide powders, and the thermoelectric properties were investigated as a function of the milling duration. Fine grain sizes were analyzed by via X-ray diffraction and scanning electron microscopy, to investigate the influence of the milling duration on the synthesized samples. It was found that microstructural changes, the Seebeck coefficient, and the electrical resistivity of the compounds were highly dependent on the sample milling duration. Additionally, the carrier concentration considerably increased in the samples milled for 6 h; this was attributed to the formation of antisite defects introduced by the accumulated thermal energy. Moreover, the highest value of ZT (=1.05) was achieved at 373K by the 6-h milled samples. The temperature at which the ZT value maximized varied according to the milling duration, which implies that the milling duration of the three thermoelectric composite oxide powders should be carefully optimized for their effective application.

The principle of work of many metallurgical shaft furnaces is based on the flow of reaction gas through the descending packed bed composed of metallurgical materials. Hot gases flow up the shaft furnace through the column of materials, give their heat to the descending charge materials. At the same time due to their reducing nature they interact chemically, causing the reduction of oxides inside the charge. In real conditions, during the course of the process, the powder is generated, the source of which is the batch materials or it is introduced into the as part of the process procedure. The powder in the form of thin slurry is carried by the stream of flowing gas. Such multiphase flow might considerably affect the permeability of the charge due to the local holdup of powder. The holdup of solid phase in packed beds of metallurgical shaft furnaces leads to radial changes in bed porosity. Radial changes in bed porosity uneven gas flow along the radius of the reactor and negatively affect the course and efficiency of the process. The article describes the model studies on radial distribution of carbon powder holdup in the packed bed composed of metallurgical materials. The powder was divided into fractions – “static” and “dynamic”. Large diversity of carbon powder distribution was observed in the function of the radius of reactor in relation to the bed type, apparent velocity of gas carrying powder and the level of bed height.

Pre-alloyed Astaloy CrLTM (Fe-1.5 wt% Cr-0.2 wt% Mo), a commercial Fe-based alloy powder for high strength powder metallurgy products, was sintered and hot forged with additions of 0.5 wt% C and 0~2 wt% Cu. To investigate the influence of various Cu contents, the microstructural evolution was characterized using density measurements, scanning electron microscope (SEM) and electron backscatter diffraction (EBSD). Transverse rupture strength (TRS) was measured for each composition and processing stage. The correlation between Cu additions and properties of sinter-forged Fe-Cr-Mo-C alloy was discussed in detail.

Porous metals show not only extremely low density, but also excellent physical, mechanical and acoustic properties. In this study, Hastelloy powders prepared by gas atomization are used to manufacture 3D geometries of Hastelloy porous metal with above 90% porosity using electrostatic powder coating process. In order to control pore size and porosity, foam is sintered at 1200~1300°C and different powder coating amount. The pore properties are evaluated using SEM and Archimedes method. As powder coating amount and sintering temperature increased, porosity is decreased from 96.4 to 94.4%. And foam density is increased from 0.323 to 0.497 g/cm3 and pore size is decreased from 98 to 560 μm. When the sintering temperature is increased, foam thickness and strut thickness are decreased from 9.85 to 8.13mm and from 366 to 292 μm.

This article discusses results of an analysis of mechanical properties of a sintered material obtained from a mixture of elemental iron, copper and nickel powders ball milled for 60 hours. The powder consolidation was performed by hot pressing in a graphite mould. The hot pressing was carried out for 3 minutes at 900 °C and under a pressure of 35 MPa. The sintered specimens were tested for density, porosity, hardness and tensile strength. Their microstructures and fracture surfaces were also examined using a scanning electron microscope (SEM). The study was conducted in order to determine the suitability of the sintered material for the manufacture of metal-bonded diamond tools. It was important to assess the effects of chemical composition and microstructure of the sintered material on its mechanical properties, which were compared with those of conventional metal bond material produced from a hot-pressed SMS grade cobalt powder. Although the studied material shows slightly lower strength and ductility as compared with cobalt, its hardness and offset yield strength are sufficiently high to meet the criteria for less demanding applications.

Recently, attempts have been made to use porous metal as catalysts in a reactor for the hydrogen manufacturing process using steam methane reforming (SMR). This study manufactured Ni-Cr-Al based powder porous metal, stacked cubic form porous blocks, and investigated high temperature random stack creep property. To establish an environment similar to the actual situation, a random stack jig with a 1-inch diameter and height of 75 mm was used. The porous metal used for this study had an average pore size of ~1161 μm by rolling direction. The relative density of the powder porous metal was measured as 6.72%. A compression test performed at 1073K identified that the powder porous metal had high temperature (800°C) compressive strength of 0.76 MPa. A 800°C random stack creep test at 0.38 MPa measured a steady-state creep rate of 8.58×10–10 s–1, confirming outstanding high temperature creep properties. Compared to a single cubic powder porous metal with an identical stress ratio, this is a 1,000-times lower (better) steady-state creep rate. Based on the findings above, the reason of difference in creep properties between a single creep test and random stack creep test was discussed.

Microwave sintering process was employed to agglomerate ferromanganese alloy powders. The effects of sintering temperature, holding time and particle size composition on the properties and microstructure of sintering products were investigated. The results was shown that increasing sintering temperature or holding time appropriately is beneficial to increase the compressive strength and volume density. SEM and EDAX analysis shows that the liquid phase formed below the melting point in the sintering process, which leads to densification. XRD patterns indicate that the main reaction during microwave sintering is the decarbonization and carburization of iron carbide phase. The experiment demonstrate that the optimum microwave sintering process condition is 1150°C, 10 min and 50% content of the powders with the size of –75 μm

Thermal/cold spray deposition were used for additive manufacture of oxide dispersion strengthened (ODS) steel layers. Mechanically alloyed F/M ODS steel powders (Fe(bal.)-10Cr-1Mo-0.25Ti-0.35Y2O3 in wt.%) were sprayed by a high velocity oxygen fuel (HVOF) and cold spray methods. HVOF, as a thermal method, was used for manufacturing a 1 mm-thick ODS steel layer with a ~95% density. The source to objective distance (SOD) and feeding rate were controlled to achieve sound manufacturing. Y2Ti2O7 nano-particles were preserved in the HVOF sprayed layer; however, unexpected Cr2O3 phases were frequently observed at the boundary area of the powders. A cold spray was used for manufacturing the Cr2O3-free layer and showed great feasibility. The density and yield of the cold spray were roughly 80% and 45%, respectively. The softening of ODS powders before the cold spray was conducted using a tube furnace of up to 1200°C. Microstructural characteristics of the cold sprayed layer were investigated by electron back-scattered diffraction (EBSD), the uniformity of deformation amount inside powders was observed.

Usually porous metals are known as relatively excellent characteristic such as large surface area, light, lower heat capacity, high toughness and permeability for exhaust gas filter, hydrogen reformer catalyst support. The Ni alloys have high corrosion resistance, heat resistance and chemical stability for high temperature applications. In this study, the Ni-based porous metals have been developed with Hastelloy powder by gas atomization and water atomization in order to find the effects of powder shape on porous metal. Each Hastelloy powder is pressed on disk shape of 2 mm thickness with 12 tons using uniaxial press machine. The specimens are sintered at various temperatures in high vacuum condition. The pore properties were evaluated using Porometer and microstructures were observed with SEM.

The objective of the present study was to investigate the effects of Sn addition on the mechanical and corrosion properties of Mg-1Zn-1Zr-xSn (x = 1, 2, 3, 4, 5 wt.%) alloys prepared by powder-in-tube rolling (PTR) method. The PTR-treated Mg alloys reached 98.3% of theoretical density. The hardness of the alloy increased with Sn addition. Two main intermetallic phases, Mg2Sn and Zn2Zr3, were formed in the alloys. The Mg2Sn intermetallic particles were observed along the grain boundaries, while the Zn2Zr3 particles were distributed in the Mg matrix. The addition of 1 wt. % Sn caused the corrosion potential to shift toward a more positive value, and the resulting alloy exhibited low corrosion current density.

U-type ferrite typified by Ba4Co2Fe36O60 is used as a RAM (Radar Absorbing Materials) in the X-band (8-12 GHz). Ba4Co2Fe36O60 is known to have a complex crystal structure, which makes it difficult to obtain single phase and have low reproducibility. Previously known U-type ferrites have been fabricated based on a ceramic process that mixing (by a ball mill), calcining, grinding, binder mixing, drying, sieving, pressing and sintering. In contrast, the process of preparing the powder by the sol-gel method and its heat-treating is advantageous in that it can reduce the process steps and the required time. In addition, the precise stoichiometric control by the sol-gel method can effectively evaluate the effect of added or substituted elements. In this study investigates the crystal structure of Ba4Co2Fe36O60 synthesized by the sol-gel method and the morphology of U-type ferrite nano-powders according to various heat treatment conditions. Analysis of the crystal structure is used for XRD. Morphology and size are observed by SEM. In addition, VSM is performed to confirm the change of magnetic properties according to various heat treatment conditions.

The computational intelligence tool has major contribution to analyse the properties of materials without much experimentation. The B4C particles are used to improve the quality of the strength of materials. With respect to the percentage of these particles used in the micro and nano, composites may fix the mechanical properties. The different combinations of input parameters determine the characteristics of raw materials. The load, content of B4C particles with 0%, 2%, 4%, 6%, 8% and 10% will determine the wear behaviour like CoF, wear rate etc. The properties of materials like stress, strain, % of elongation and impact energy are studied. The temperature based CoF and wear rate is analysed. The temperature may vary between 30°C, 100°C and 200°C. In addition, the CoF and wear rate of materials are predicted with respect to load, weight % of B4C and nano hexagonal boron nitride %. The intelligent tools like Neural Networks (BPNN, RBNN, FL and Decision tree) are applied to analyse these characteristics of micro / nano composites with the inclusion of B4C particles and nano hBN % without physically conducting the experiments in the Lab. The material properties will be classified with respect to the range of input parameters using the computational model.

The effect of the compaction rate on the structure, microstructure and properties of Fe-Al sinters obtained during the SHS reaction is presented in this paper. It was found that increasing the uniaxial pressing pressure led to the increase of the contact area between iron and aluminium particles, which improved the conduction and lowered heat losses during the self-propagating high-temperature synthesis (SHS) reaction and thus result with a sintered material with an improved phase homogeneity. On the other hand, an increase in the pressing pressure causes air be trapped in the pores and later on reacts with iron and aluminium to form oxides. In this work, the shrinkage course was analysed at six different pressing pressures: 50, 100, 150, 200, 300 and 400 MPa. The green compacts were then subjected to the PAIS process (pressure-assisted induction sintering) at a temperature of 1000°C under a load of 100 kN for 5 min. Such prepared samples were subjected to density, porosity, and microhardness (HV0.1) measurements. X-ray diffraction phase analysis and SEM observations were performed together with EDS chemical composition measurements. For studied chemical composition of the samples and sample geometry, 200 MPa compacting pressure was found to be optimal in order to obtain the best sample homogeneity.

The paper presents the results of research on the production and application of sintered copper matrix composite reinforced with titaniumcopper intermetallic phases. Cu- Ti composites were fabricated by powder metallurgy. The starting materials for obtaining the sintered composites were commercial powders of copper and titanium. Experiments were carried out on specimens containing 2.5, 5, 7.5 and 10 % of titanium by weight. Finished powders mixtures containing appropriate quantities of titanium were subjected to single pressing with a hydraulic press at a compaction pressure of 620 MPa. Obtained samples were subjected to sintering process at 880 °C in an atmosphere of dissociated ammonia. The sintering time was 6 hours. The introduction of titanium into copper resulted in the formation of many particles containing intermetallic phases. The obtained sinters were subjected to hardness, density and electrical conductivity measurements. Observations of the microstructure on metallographic specimens made from the sintered compacts were also performed using a optical microscope. An analysis of the chemical composition (EDS) of the obtained composites was also performed using a scanning electron microscope. Microstructural investigations by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) showed that after 6 hours of sintering at 880°C intermetallic compounds: TiCu, TiCu2, TiCu4, Ti2Cu3, Ti3Cu4 were formed. The hardness increased in comparison with a sample made of pure copper whereas density and electrical conductivity decreased. The aim of this work was to fabricate copper matrix composites reinforced with titanium particles containing copper- titanium intermetallic phases using powder metallurgy technology and determine the influence of the titanium particles on the properties of the sintered compacts and, finally, analyse the potentials application for friction materials or electric motors brushes.

The main purpose of the work was to determine the powder influence of the powder preparation on the microstructure and properties of iron-based sinters used as a metallic-diamond matrix. The sinters obtained from a mixture of comercial powders were used for research. A mixture of powders was selected for the tests, in which the mass fractions of individual powders were as follows: 60% Fe, 23.8% Cu, 4.2% Sn and 12% Ni. The powders were pre-mixed in a Turbula mixer and next a part of material was subjected to milling in a ball mill. Sintering was performed using hot-pressing technique in a graphite mould. The investigated properties of the sinters were concerned density, porosity, hardness, oxygen content, static tensile test and analysis of microstructure. Spot chemical analysis revealed the presence of Fe solution, Cu solution and the presence of iron oxides oxides. Nickel atoms were present throughout the sinter volume. The obtained test results showed that the presented sinter has good functional properties (hardness and thermal expansion) and can be used as a diamond-metal composite matrix in diamond tools.The microstructure and mechanical properties of sinters were investigated.

The mechanical and tribological properties of the Al/CNT composites could be controlled and improved by the method of its fabrication process. This research article deals with the optimization of mechanical and tribological properties of Al/CNT composites, which are fabricated using the mechanical alloying process with the different weight percentage of multi-walled CNT reinforcement. The phase change and the presence of CNT are identified using the X-Ray Diffraction (XRD) analysis. The influence of mechanical alloying process and the multi-walled CNT reinforcement on the mechanical, and tribological behaviours of the Al/CNT composites are studied. The optimal mechanical alloying process parameters and the weight percentage of multi-walled CNT reinforcement for the Al/CNT composite are identified using the Response Surface Methodology (RSM), which exhibits the better hardness, compressive strength, wear rate and Coefficient of Friction (CoF). The Al/CNT composite with 1.1 wt.% of CNT has achieved the optimal responses at the milling speed 301 rpm and milling time 492 minutes with the ball to powder weight ratio 9.7:1, which is 98% equal to the experimental result. This research also reveals that the adhesive wear is the dominant wear mechanism for the Al/CNT composite against EN31 stainless steel but the optimal Al/CNT composite with 1.1 wt.% of multi-walled CNT has experienced a mild abrasive wear.

This study investigates the effects of repetitive injection molding on the properties of feedstock using the AISI 4140 feedstock. The properties of feedstock are evaluated from the mixing homogeneity of powder and binder, rheological properties, and dimensional accuracy of parts sintered. The feedstock after the 1st injection molding shows a better homogeneity than as-received feedstock due to re-mixing effects between the screw and barrel during the injection molding process. As the number of recycling numbers increases, the homogeneity, viscosities ad shrinkage ratio of recycled feedstocks show slight differences with those of the as-received feedstock until the 6th molding injection. However, some rheological parameters like the moldability index sharply increased up to the 4th injection but shows a tendency to decrease thereafter.

This study evaluated the effect of milling speed and compaction pressure on the densification and morphology of the CuZn-Gr composite. The composite was prepared by using the powder metallurgy technique. The effect on the microstructural and compaction was determined based on different milling speeds. The different milling speeds involved were 175, 200, 225, and 250 rpm. Meanwhile, the different compaction pressures used in this study were 127, 250, 374, and 500 MPa. The properties of the milled powder gave the result to green density and densification parameters. The XRD pattern of Cu and Zn broadened as milling time increased.

With the recent advancement in technology for titanium metal powder injection molding and additive manufacturing, high yield and good flowability powder production is needed. In this study, titanium powder was produced through vacuum induction melting gas atomization with a cold crucible, which can yield various alloy compositions without the need for material pretreatment. The gas behavior in the injection section was simulated according to the orifice protrusion length for effective powder production, and powder was prepared based on the simulation results. The gas distribution changes with the orifice protrusion length, which changes the location of the recirculation zone and production yield of the powder. The produced powders had a spherical morphology, and the content of impurities (N, O) changed with the injected-gas purity.