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A Standard-free method, which has been developed by ourselves, was applied to powdered biomedical samples to which a conventional method of quantitative analysis, such as an internal standard method, can not be successfully applied. First, NIST-Bovine liver and NIES-rice targets, which are powdered as they are, were analyzed by the standard-free method and correct quantitative values of potassium and manganese concentration, which are consistent with those obtained by the conventional internal standard method, were obtained. Furthermore, for relative values of concentration of various elements, almost the best results we have ever had were obtained. Next, the present method has been successfully applied to a hard tissue sample (mouse bone), which is quite difficult to be accurately analyzed by the internal standard method. In order to solve the problem of falling off of powdered samples from a backing film, a carbon tape with an adhesive agent has been examined and found to be quite effective.

Availability of a powdered internal standard method developed in the previous report has been investigated in detail for geological, mineralogical, environmental and biological samples. It is found that this method is effective for various powdered samples composed of high-Z elements. A computer program for correcting self-absorption of x-rays, which is based on the method we previously reported, was developed and it has been applied to soil samples of varied thickness. As a result, it is found that the method is quite effective even for a pretty thick target where particles overlap with each other. Moreover, the method was applied to several rock samples, which were prepared by grinding and consist of particles of divergent size, and found to be applicable. Lastly, the powdered internal standard method was applied to a biological sample and found to be almost satisfactory, too. These results demonstrate the availability of the powdered internal standard method combined with the method of x-ray-absorption correction for samples in many research fields.

An amorphous/nanocrystalline 50Ni–50Ti powder was produced from elemental Ti and Ni powders by solid state synthesis utilizing low energy mechanical alloying with times up to 100 h. The morphology, microstructure, and phase composition of the milling products were evaluated by using scanning electron microscopy and X-ray diffraction analysis. The results indicated that there was no chemical reaction between the elements during the milling process, which led to the direct formation of an amorphous/nanocrystalline structure without any intermediate phase (intermetallic and/or solid solution phase) formation. It seems that the second kind of amorphization process proposed by Weeber and Bakker is governed. It was shown that the formation of amorphous phase was started after 80 h and developed during the milling for 100 h.

In powder-mixed electrical discharge machining (PMEDM), the application of low-frequency vibrations to a workpiece is considered beneficial to the machining quality. This study evaluates the average surface roughness (Ra) of SKD61 steel workpieces subjected to low-frequency vibrations during PMEDM using a Cu electrode and titanium powder. Specifically, Taguchi’s L25 experimental design method is used to evaluate the influence of the following process parameters: current, pulse-on time, concentration, push pressure, frequency, and amplitude. The analysis of variance technique is used to determine the minimum Ra (Ra${}_{min}$) value. The results show that Ra is most and least strongly influenced by $I$ and $A$, respectively. Further, Ra${}_{min}$ is found to be 1.03 $\mu$m.

The granularity distribution of powder is shown to have the fractal characters. Based on the fractal theory, three algebraic expressions for the fractal dimension, the cumulative probability and the mass distribution of particles were obtained. Three expressions are the functions of the concentration of particles, the diameter of particles, the maximum and the minimum particle diameters. No additional empirical constant is introduced in these expressions. These fractal models contain less empirical constants than the conventional correlations. The fractal behavior about coal particles was discussed in detail. Simulations were also performed by fractal Monte Carlo technique. The proposed technique may provide us a new approach to analyze the granularity distribution of powder.

This experimental study explores the possibility of pattern generation in the reverse electric discharge machining (EDM) process using powder metallurgical (PM) sintered tool electrodes. The experimentation is conducted to generate a complex-shaped pattern by transferring tool materials using PM sintered tools on the surface of Aluminium 6061. The selected controlling process parameters are compact load (CL), pulse on-time ($T_{\mathrm{\text{on}}}$), and peak current ($I_p$) where surface roughness (Ra) and edge deviation (ED) are chosen as output parameters. A minimum Ra of 2.6$\mu$m and minimum ED of 14.79$\mu$m are obtained at CL of 20 tons, $I_p$ of 2A and $T_{\mathrm{\text{on}}}$ of 100$\mu$s. The surface characteristics of the deposited pattern are analyzed by FESEM, EDS, and XRD studies which confirm the migration of tool constituents on the pattern surface. The thickness of the deposit is found to be 86.25$\mu$m. The migration of tool particles increases the surface hardness more than four times of base material.

Glucose, carbamide and petroleum coke as carbon sources are separately added to butyl titanate and ethanol system. The initial powder containing titanium source and carbon source is prepared by sol–gel method. IR analysis of the initial powder shows that: glucose-butyl titanate system and carbamide-butyl titanate system form water-soluble compounds. After being dried, they form Ti₂O₃ and C mixed powder. Petroleum coke-butyl titanate system forms TiO₂ powder with nanometer size in carbon. Regarding initial powder as a raw material, titanium nitride powder is prepared by carbon thermal reduction. The XRD analysis shows that the titanium nitride powder is formed after the initial powder prepared in petroleum coke-butyl titanate system is kept at 1350°C for 5 h. The added Fe₂O₃ accelerates the synthesis of titanium nitride; the initial powder prepared in glucose-butyl titanate is kept at 1400°C for 5 h and then synthesizes the titanium nitride powder. Fe₂O₃ does not accelerate the synthesis of titanium nitride. The initial powder prepared in carbamide-butyl titanate system is found to form volatile material in N₂, but no titanium nitride powder is found.

Boron carbide is one of the advanced ceramic materials which is used in a wide range of applications. However, this material needs a high sintering temperature (~2200°C). Using nano-size powders for producing ceramic parts results in lowering sintering temperature and also enhances toughness and hardness of the material. One of the methods for producing ceramic nano powders is attrition milling. However, as the milling balls and wall are made of steel, some impurities specially iron will be introduced to the powder during milling. Chemical analysis of the milled powder shows that more than 33wt% of the powder consists of iron. These uncontrolled impurities affect the mechanical and physical properties of sintered ceramic parts that are made of such a powder. Therefore, these impurities must be removed from the powder. Hydro metallurgical beneficiation technique with two different solvents has been used for purification of the powder. The result of chemical analysis after purification showed that the weight percentage of iron in powder dropped to 9% and 0.8% (depending on the solvents). Moreover, the sintering behavior of hot-pressed boron carbide powder with different percentages of iron as sintering aid has been studied. The results showed excellent densification and hardness of the sintered parts.

We report on a novel synthetic method of microwave processing with a domestic 2450MHz microwave synthesis system to prepare ZnO fiber using pure ZnO powder. We also studied and report on structure and morphology of the resultant products by XRD and SEM. XRD revealed that a single phase ZnO fiber can be synthesized quickly and easily by microwave processing. The results indicate that microwave processing is a promising method of processing ZnO fiber.

Strontium hexaferrite powder synthesised conventionally has been treated in nitrogen atmosphere and subsequently calcined in air (Nitrogen Treatment and Re-calcination : NTR Process). The phase identification studies by means of X-ray diffraction (XRD) showed decomposition of strontium hexaferrite and reduction of the resultant iron oxide (Fe₂O₃) during the reaction with nitrogen. According to high resolution scanning electron microscopy (HRSEM) studies, reduction during nitrogenation, resulted in the division of some big grains into much finer sub-grains, strontium hexaferrite, Fe₃O₄ and Sr₇Fe₁₀O₂₂ were the main phases obtained after reduction. The hexaferrite phase reformed on subsequent calcination. The magnetic measurements indicated a significant decrease in the intrinsic coercivity during nitrogenation due to the formation of Fe₃O₄. However, after a re-calcination process, the remanence and maximum magnetisation (i.e. magnetisation at 1100 kA/m ) exhibited values close to the initial values before treatment but the value of the intrinsic coercivity was higher than that prior to nitrogenation. The microstructure showed that this could be attributed to very fine grains which originated from the fine sub-grains formed during nitrogenation.

The selected temperature was 950°C for nitrogenation and 1000°C for re-calcination. The time and initial pressure were selected to be 5 hours and 1 bar respectively. The highest coercivity obtained after re-calcination was 340 kA/m.

Mechanical alloying (MA) as a powder metallurgy method is often used to prepare materials with ultrafine grain and special structure difficultly obtained in conventional ways. In this paper, the TiH₂45Al4Sn (at. %) composite powder was mechanically milled by high energy ball milling. The crystalline grain size, morphology and phase characteristic of milled powder with different milling time were investigated by XRD, SEM and TEM. The results show that with the milling time increasing, the powder particles are refined rapidly in the initial stage and then gradually become stable. The new phase Ti₂Sn₃ is formed by mechanical alloying (MA) of TiH₂, Al, Sn powders during milling which resulted particles refinement to very small size. The homogeneous and dense Ti₂Al and Ti₂Sn₃ intermetallic compounds are obtained after vacuum hot pressing sintering, which microstructure is composed of equal axial Ti₂Al as matrix and fine Ti₂Sn₃ particles. Because of the addition of Sn, Ti-Al intermetallic compounds formation is inhibited during MA and sintering. However, Sn contributes to the formation of Ti₂Al phase which which is difficult to be obtained with the conventional method of casting and forging.