Production and Characterization Of Electroless Ni Coated Fe-Co Composite Using Powder Metallurgy In Microwave Furnace

The specimens, magnetic properties materials, and microwave characteristics of Ni coated Fe and Co composites were researched by specimens produced by microwave furnace sintering at 1100°C temperature. A uniform nickel deposit on Fe-Co particles was coated previously to sintering by electroless coating deposition procedure. A composite consisting of quaternary additions, a metallic phase, Fe-Co inside of Ni matrix has been prepared under in a neutral atmosphere environment then microwave sintered. X-Ray Diffraction, SEM(Scanning-Electron-Microscope), Empedans Phase Analyzer were utilized to obtain structural data and to determine magnetic and electrical features such as dielectric and conductivity at the temperature range of 25-400C. The ferromagnetic resonance varied from 10 Hz to 1GHz and measurements were employed to characterize the features of the specimens. Empirical of findings obtained for the composition (Fe-%25Co)50Ni at 1100°C recommend that the best conductivity and hardness were obtained with 50Ni addition at a sintering temperature of 1100°C.

Research on Control Factors and Performance of YAG Porous Ceramics

In this paper, the YAG powder is prepared by the co-precipitation method. In addition, the sintering aid to aid sintering and the high temperature foaming agent that becomes gas released during the heating process so that the sample has pores, the ball mill mixes the material, and the sample press is extruded. Box-type resistance furnace sintering. Through this process, porous ceramics can be made. Study the effect of sintering aid content, foaming agent type, sintering temperature on the properties of YAG porous materials. The analysis and discussion can lead to the following conclusions: as the content of sintering aid silica in the sample increases, the sintering temperature of the sample decreases. It is best when the ratio of sintering aid alumina to silica is 3:1. The moldability of the sample whose foaming agent is wood chips is worse than that of the sample whose foaming agent is fiber and carbon powder. The ratio of sintering aid alumina to silica is 3:1, and the sintering temperature of the sample with carbon powder as the blowing agent is best when the sintering temperature is 1400 °C.

Ultra-Fast Laser Fabrication of Alumina Micro-Sample Array and High-Throughput Characterization of Microstructure and Hardness

In the light of recent advances in material informatics, there is a great demand for high-throughput approaches of sample fabrication and property characterization. Currently, no high-throughput approach has been demonstrated for the fast sampling of the microstructure and the correlated properties. In this paper, we demonstrate the ultra-fast fabrication of an alumina sample array and the high-throughput hardness characterization of these sample units. The alumina sample array was fabricated using picosecond (PS) laser micromachining and CO2 laser sintering within a short time (i.e., less than a few minutes). After laser sintering, the hardness of these sample units was characterized using micro-indentation, and the microstructure was observed using scanning electron microscopy (SEM). In each sample unit, the microstructure was uniform for the entire top surface and within about 20 µm depth from the top surface. The relative density (RD) and corresponding micro-hardness of the sample units was found to continuously vary over a wide range from 89% RD with 600 kgf/mm2 hardness to 99% RD with 1609 kgf/mm2 hardness. For these laser-sintered samples, the correlation of hardness and relative density of the alumina matched well with the literature reports on sintered alumina obtained using conventional low-throughput furnace sintering experiments.

Medium-Frequency Electrical Resistance Sintering of Soft Magnetic Powder Metallurgy Iron Parts

The fabrication of soft magnetic Fe parts by the medium-frequency electrical resistance sintering (MF-ERS) technique is studied in this paper. This consolidation technique involves the simultaneous application to metallic powders of pressure and heat, the latter coming from the Joule effect of a low-voltage and high-intensity electric current. Commercially pure iron powder was used in the consolidation experiences. The porosity distribution, microhardness, electrical resistivity and hysteresis curves of the final compacts were determined and analysed. The results obtained were compared both with those of compacts consolidated by the conventional powder metallurgy (PM) route of cold pressing and vacuum furnace sintering, and with fully dense compacts obtained by double cycle of cold pressing and furnace sintering in hydrogen atmosphere.

Capacitor Electrical Discharge Consolidation of Metallic Powders—A Review

Manufacturing metallic materials from elemental or alloyed powders is an option in many industrial processes. Nevertheless, the traditional powder metallurgy processing including furnace sintering is at times detrimental for the microstructure attained in the powders. Alternative sintering processes based on the use of electricity and the energy obtained by the Joule effect in powder particles can be quick enough to avoid microstructural changes. In particular, when the energy is stored in a capacitor and then discharged, the heating process is extremely quick, lasting milliseconds or even microseconds. This process, generally known as electrical discharge consolidation, has been applied to a wide variety of metallic materials, easily preserving the original microstructure of the powders. Both porous or homogeneous and highly densified material can be obtained, and without losing the desired properties of the consolidated material. A general overview of the process and applications, as well as the results obtained by different research groups around the world, have been reviewed in this manuscript.

Consolidation of Titanium Powder by Electrical Resistance Sintering: Practice and Simulation

In this work, a commercially pure titanium powder has been consolidated using the Electrical Resistance Sintering (ERS) process. This technique consists in the consolidation of a powder mass by the simultaneous application of pressure (80 MPa, in this work) and heating caused by the passage of a high intensity (3.5-6.0 kA, in this case) and low voltage current (lower than 10 V), during short dwelling times (0.8-1.6 s, in this work). The resulting compacts have been mechanically characterised by measuring their microhardness distribution. The results obtained are compared with the corresponding values of compacts prepared with the same powders following the conventional P/M route of cold pressing and furnace sintering. The results of some simulations are provided to give information about the temperatures reached inside the compacts during the electrical consolidation process.

Nickel Porous Compacts Obtained by Medium-Frequency Electrical Resistance Sintering

A commercially pure (c.p.) nickel powder was consolidated by Medium-Frequency Electrical Resistance Sintering (MF-ERS). In this consolidation technique, a pressure and the heat released by a high-intensity and low-voltage electrical current are concurrently applied to a metal powder mass. A nickel powder with a high tap porosity (86%) and a low applied pressure (only 100 MPa) is chosen in order to be able to obtain compacts with different levels of porosity, to facilitate the study of the porosity influence on the compact properties. The influence of current intensity and heating time on the global porosity values, the porosity and microhardness distribution, and the electrical conductivity of the sintered compacts is studied. The properties of the compacts consolidated by MF-ERS are compared with the results obtained by the conventional powder metallurgy route, consisting of cold pressing and furnace sintering. A universal equation to describe the porosity influence on all the analyzed properties of powder aggregates and sintered compacts is proposed and validated.

Influence of Processing Parameters on the Conduct of Electrical Resistance Sintering of Iron Powders

The influence of the applied pressure and electrical parameters on the macrostructure of specimens consolidated by the medium-frequency electrical resistance sintering technique (MF-ERS) is analysed in this work. This technique is based on the application of pressure to a mass of conductive powder that, simultaneously, is being crossed by a high intensity and low voltage electric current. The simultaneous action of the pressure and the heat released by the Joule effect causes the densification and consolidation of the powder mass in a very short time. The effect of the current intensity and heating time on the global porosity, the porosity distribution, and the microhardness of sintered compacts is studied for two applied pressures (100 and 150 MPa). For the different experiments of electrical consolidation, a commercially available pure iron powder was chosen. For comparison purposes, the properties of the compacts consolidated by MF-ERS are compared with the results obtained by the conventional powder metallurgy route (cold pressing and furnace sintering). Results show that, as expected, higher current intensities and dwelling times, as well as higher pressures and the consolidation of compacts with lower aspects ratios, produce denser materials.

TECHNOLOGY FOR PRODUCING COMPOSITE GLASS-CRYSTAL FACING MATERIALS BASED ON MIXED CULLET

An effective energy-saving technology for producing composite glass-crystal facing materials based on fractionated cullet of sheet and container glasses, cullet of porcelain and sodium liquid glass has been developed. The use of fine porcelain powder in the composition of composite glass-crystal facing materials in an amount of up to 10 wt is justified. % and liquid sodium glass up to 5 wt. %. It is shown that the optimal fractional composition of granulated mixed cullet is 35 wt. % fraction 0.63-0.80 mm; 35 wt. % - fractions of 0.80-1.25 mm and 30 wt. % fraction of 1.25-3.15 mm. Polytherms of viscosity of colorless, green and brown container glasses, as well as sheet glass, are calculated. The possibility of using mixed cullet for obtaining composite glass-crystal facing materials is on the basis of obtained dependencies. The chemical composition of sheet and container glasses and porcelain is studied using x-ray fluorescence analysis. Optimal charge compositions have been developed to obtain glass-crystal materials with compressive strength up to 79 MPa. The technology of obtaining composite glass-ceramic facing material includes the following technological operations: milling of glass breakage; grinding cullet of porcelain; drying of sodium liquid glass; the screening of crushed cullet on fractions; the grind of crushed cullet of China; grinding the dried sodium silicate glass; weighing the components in accordance with the developed formulations, the averaging of the graded cullet with fine porcelain; averaging the mixture of finely ground dried sodium silicate glass; stacking the mixture in a metal mold; compaction of the mixture in metal molds; heat treatment in a muffle furnace (sintering); extraction of facing tiles from molds; trimming the edges of the tiles with a diamond saw; quality control of finished products.

Synthesis and Characterization of the CaTiO3:Eu3+ Red Phosphor by an Optimized Microwave-Assisted Sintering Process

The synthesis process has a significant influence on the properties of Ca1-xTiO3:Eu3+x phosphors; thus, an optimized process will lead to a better performance of the Ca1-xTiO3:Eu3+x phosphors. In this work, the feasibility of synthesizing the Ca1-xTiO3:Eu3+x phosphor with a good luminescent performance by combining the chemical co-precipitation method and microwave-assisted sintering was studied. The precursor of Ca1-xTiO3:Eu3+x phosphors were prepared by the chemical co-precipitation method. To find an optimized process, we applied both of the traditional (furnace) sintering and the microwave-assisted sintering to synthesize the Ca1-xTiO3:Eu3+x phosphors. We found out that a sintering power of 528 W for 50 min (temperature around 950 °C) by a microwave oven resulted in similar emission intensity results compared to traditional furnace sintering at 900 °C for 2.5 h. The synthesized Ca1-xTiO3:Eu3+x phosphors has an emission peak at 617 nm (5D0→7F2), which corresponds to the red light band. This new synthesized method is an energy efficient, time saving, and environmentally friendly means for the preparation of Ca1-xTiO3:Eu3+x red phosphor with good luminescent performance.