Pure Powder Research Articles

Effect of Ti/Nb content on microstructure evolution and wear properties of in-situ (Ti,Nb)C reinforced composite coatings by plasma spray welding

Due to their superior wear resistance, multi-particle reinforced composite coatings have caught the interest of numerous researchers. In this research, a method of preparing composite coatings containing in-situ (Ti,Nb)C particles was proposed using plasma spray welding with a mixture of Fe-based alloy, pure Ti, and pure Nb powders. The research involved a detailed analysis of the nucleation mechanism, particle shape and strengthening behavior of (Ti,Nb)C particles in the composite coatings with different atomic ratio of Ti/Nb. The microstructure and phase were examined, and the wear resistance was tested and examined. The phase analysis results manifested that the composite coatings had primarily (Ti,Nb)C reinforcing phase and α-Fe matrix. The (Ti,Nb)C particles were not added in the raw powders, but in-situ generated via the reactions between the powders. The microstructure analysis results indicated that the reinforced particles transformed from irregular dendritic particles into lumpy and spherical particles, and then into an interspersed distribution of laths and spheres as the atomic ratio of Ti/Nb decreased. The microhardness value of these composite coatings when the Ti/Nb ratios were different were 550 HV–650 HV, while the microhardness value of the steel was 174 HV. However, with the increase of Ti/Nb atomic ratio, the change of wear resistance showed the trend: increase → decrease → increase. In-situ (Ti,Nb)C particles were uniformly distributed in the coatings and beneficial to improving the wear resistance. When Ti/Nb ratio is 1:1, the mass loss of the composite coating was only 0.6 mg, which was a quarter of the steel substrate (2.4 mg).

Laser Powder Bed Fusion Processing of Low Cost CoCrFeNiMoxNby High Entropy Alloys with Promising High-Temperature Properties via In Situ Alloying Commercial Powders

A blend of only commercial powders, including Ni625, CoCrF75, and 316L, were used as the raw material for fabricating non-equiatomic CoCrFeNiMoxNby high entropy alloys (HEAs) through laser powder bed fusion (PBF-LB/M) via in situ alloying, instead of using pure elemental powders, thus reducing the raw materials cost. The rapid cooling inherent in the PBF-LB/M process facilitated the dissolution of Mo and Nb, resulting in a single FCC phase characterized by high relative densities. High-temperature tensile tests were conducted at room temperature, 700 °C, 800 °C, and 900 °C, revealing mechanical properties that surpassed those reported in existing HEA literature. The remarkable strength of the HEAs developed in this study primarily stemmed from the incorporation of Mo and Nb, leading to the precipitation of Mo and Nb-rich lave phases at elevated temperatures. While constraining elongation when confined to grain boundaries, these precipitates enhanced strength without compromising elongation when distributed throughout the matrix. This work is a feasibility study to explore the usage of commodity compositions from the market to develop HEAs using PBF-LB/M, which opens the possibility of using scraps to further the development of new materials. Consequently, this study presents a rapid and cost-effective approach for HEA development, improving efficiency and sidestepping the direct utilization of critical raw metals for sustainable manufacturing. Moreover, this work also underscores the outstanding mechanical performance of these HEAs at high temperatures, paving the way for the design of innovative alloys for future high-temperature applications.

Fabrication and mechanical properties of multi-principal cation (Mg,Ti,Cr,Zr,Al,Si) mullite ceramic

Milti-principal cation oxide ceramics with excellent mechanical properties for potential applications in coating materials. A Multi-principal cation mullite (MPCM) ceramic is synthesized with MgO, TiO2, Cr2O3, ZrCl2O·8H2O and Al2O3, SiO2 via solid state reaction at 1600 °C. It is determined that 96.9 % of the sample composition is mullite. MPCM ceramic exhibits higher compressive strength (981 ± 19 MPa) and fracture toughness (3.37 ± 0.05 MPa∙m1/2), the compressive strength has raised by 453 MPa, and the added value of solution strengthening (452 MPa) is gained by using solid-solution strengthening theory. The improvement of compressive strength is mainly due to the solution strengthening effect of the four oxides(Mg, Ti, Zr, Cr), and the improvement of fracture toughness is caused by the grain hindrance during crack propagation. Moreover, its application at the high-temperature resistant coating is verified through experimentation. The interfacial binding force, as an important mechanical property index for ceramics, is researched. In this study, pure mullite powder and MPCM powder are coated onto the refractory TaWNbV alloy matrix by slurry coating method, and the interfacial toughness of the two coatings mingled with the matrix is calculated to be 72.9 and 62.6 J·m−2, respectively. The “shrinking cylinder” model is introduced to interpret the oxidative weight gain mechanism of the two coatings.

Cold spray deposition of high density polyethylene composite powders

In this paper, we investigate the use of the cold spray additive manufacturing technique to deposit micron-sized composite particles of high-density polyethylene (HDPE) compounded with either micron or nanometer sized particles of silicon dioxide (SiO2) or copper (Cu). In this study, the mass fraction of the SiO2 and copper particles added into the final composite powders was varied between 0.5 % and 9.1 % and the deposition efficiency of each composite powder was measured. Deposition of the composite powders onto an HDPE substrate was successful even at the highest particle loadings tested. In each case, an optimal mass fraction of silicon dioxide or copper particles was observed with a maximum value of deposition efficiency larger than that of the pure HDPE. For the silicon dioxide composite powders, the deposition efficiency nearly doubled compared to the pure HDPE powders. The improvement of deposition efficiency at moderate particle loadings is likely due to the increase in the impact kinetic energy of the particles resulting from the increase in the density of the composite powders. While the decrease in deposition efficiency at high particle loadings is likely the result of the increased coverage of the silicon dioxide and copper particles on the surface of the HDPE powders limiting the interaction between the HDPE of the composite powder with the HDPE substrate. SEM images show that it is possible to create a smooth, dense, and uniform thin-film polymer composite coating using cold spray.

The Solvent Role for the Decomposition of Paracetamol in Distilled and Drinking Water by Pure and Ag-Modified TiO2 Sol-Gel Powders.

In this study, pure TiO2 gels were synthesized by applying the sol-gel method, using Ti(IV) butoxide with the addition of two different solvents, namely ethylene glycol (EG) and isopropanol (isop), with only air moisture present. It was established using XRD that the gel prepared with the addition of EG was amorphous even at 400 °C, while the other gel was amorphous up to 300 °C. It was found that TiO2 (anatase) had a dominant crystalline phase during heating to 600 °C, while at 700 °C, TiO2 (rutile) appeared. The as-obtained powdered materials were annealed at 500 °C and subsequently underwent photocatalytic tests with paracetamol. Additionally, the TiO2 samples were modified with Ag+ co-catalysts (10-2 M), using photofixation by UV illumination. The photocatalytic activity of the Ag-modified powders was also tested in the photodegradation of a commonly used paracetamol in aqueous solution under UV light illumination. The obtained data exhibited that the annealed samples had better photocatalytic efficiency and decomposed paracetamol faster in comparison to the non-annealed sol-gel powders. The highest degradation efficiency was observed for the TBT/isop/Ag material, with degradation efficiencies average values of 65.59% and 75.61% paracetamol achieved after the third cycle of photocatalytic treatment. The co-catalytically modified powders had higher photocatalytic efficiency in comparison to the pure nanosized powders. Moreover, the sol-gel powders of TBT/EG, TBT/EG/Ag (10-2 M), TBT/isop, and TBT/isop/Ag (10-2 M) demonstrated the ability to retain their photocatalytic activity even after three cycles of use, suggesting that they could find practical use in the treatment of pharmaceutical wastewater. The observed photocatalytic efficiency and positive impact of silver make the prepared powders a desirable choice for pharmaceutical drug degradation, helping to promote environmentally friendly and effective wastewater treatment technology.

Preparation of tungsten powder by an unmixed carbon reduction method based on carbon diffusion

In this study, a new unmixed carbon reduction method was proposed for the preparation of pure W powder. The effects of reduction temperature, reduction time, carbon distance and thickness of WO3 layer on the phase of the reduction products were investigated. Results show that pure tungsten powder with a carbon content of less than 150 ppm can be prepared at 950 °C with a WO3 layer thickness of 5 mm and a carbon distance of 2 mm. Increased carbon distance and thickness of WO3 layer will lead to a decrease in the reduction ratio. Additionally, particle size of the tungsten powder gradually increases from 1 μm to 8 μm due to sintering with the extended reduction time. Furthermore, a two-stage carbon reduction process with WO2 as an intermediate product is proposed, which avoids the sintering and growth of tungsten powder particles and the particle size of tungsten powder was successfully reduced to 2 μm. This unmixed carbon reduction reduces the carbon concentration and prevents the carbonization of tungsten powder. The experiment verifies the feasibility of carbon as a reducing agent in producing pure tungsten powder by reducing WO3.

Optimization of formulation and processing conditions for the production of functional noodles containing orange-fleshed sweet potatoes and biofortified beans.

The global demand for noodles continues to increase due to their convenience, wide appeal, and affordability. Instant noodles, in particular, are popular for their easy preparation. With annual consumption reaching 106 billion servings in 2019, there is a growing awareness of the importance of healthy food options. However, most noodle types currently available commercially are of low nutritional value. This study sought to develop a protocol for the production of functional noodles consisting of orange-fleshed sweet potatoes (OFSP) puree and biofortified bean powder (BBP). Response surface methodology (RSM) was used to optimize product formulation and processing parameters. Reduced quartic models were found to adequately represent the relationship between dependent variables (hardness, moisture, protein, dietary fiber, iron, and zinc content) and independent variables (dough thickness, drying temperature, and drying time). R 2 values were 0.86-0.99, with a nonsignificant lack-of-fit (p < .05). Using numerical optimization, the optimal protocol for the production of functional noodles was determined to include formulation consisting of wheat 73%, OFSP 21.5%, and BBP 5.5%; dough thickness of 2.0 mm; drying temperature and time of 80.0°C and 143.4 min, respectively. These conditions yielded noodles with 5.9% moisture, 11.0 N hardness, 34.5% protein, 11.9% dietary fiber, 86.9 ppm (parts per million) iron, and 50.53 ppm zinc, with a desirability value of 0.82. Experimental validation demonstrated no significant difference from predicted values. Sensory evaluation rated the noodles as acceptable to consumers, with an overall acceptability of 7.8 on a 9-point hedonic scale. These results show the potential of OFSP and BBP as ingredients for acceptable and nutrient-rich noodles.

Analysis of Microbial Composition of Edible Insect Products Available for Human Consumption within the United States Using Traditional Microbiological Methods and Whole Genome Sequencing

Edible insects offer a promising protein source for humans, but their food safety risks have not been previously investigated within the United States. Therefore, the aim of this study was to investigate the microbial content of processed edible insect products. A total of eight different types of edible insect products, including diving beetles, silkworms, grasshoppers, Jamaican crickets, mealworms, mole crickets, whole roasted crickets, and 100% pure cricket powder, were purchased from a large online retailer for the analysis. All the products were purchased in August 2022 and examined between August 2022 and November 2022. Traditional microbiological methods were employed to determine microbial counts for each product type using three replicates (total number of samples = 24). This included assessing aerobic bacterial spore, lactic acid bacteria, Enterobacteriaceae, total viable counts, and the presence of Salmonella. Additionally, whole genome sequencing was employed to further characterize selected colonies (n = 96). Microbial counts data were statistically analyzed using one-way ANOVA, while sequence data were taxonomically classified using Sepia.Bacilluscereusgroup isolates underwent additional characterization with Btyper3. Product type significantly influenced total viable counts, bacterial spore counts, and lactic acid bacteria counts (P = 0.00391, P = 0.0065, and P < 0.001, respectively), with counts ranging from < 1.70 to 6.01 Log10 CFU/g, <1.70 to 5.25 Log10 CFU/g, and < 1.70 to 4.86 Log10 CFU/g, respectively. Enterobacteriaceae were only detected in mole crickets (<2.30 Log10 CFU/g) and house cricket powder (<2.15 Log10 CFU/g). All samples were negative for Salmonella. Whole genome sequencing revealed the presence of 12 different bacterial genera among the analyzed isolates, with a majority belonging to the Bacillus genus. Some of the isolates of Bacillus cereus group were identified as biovar Emeticus. Overall, although edible insects offer a promising food alternative, the presence of Bacillus cereus group in some products could raise concerns regarding food safety.

Development of 3β,4α-dihydroxy-5α-androstan-17-one standard solution for doping analyses.

Doping analyses are essential for sporting events because some athletes might use prohibited substances to win games. To obtain reliable results from doping analyses, it is important to use both reliable standard solutions and validated analytical methods at accredited laboratories. Among the focused compounds related to prohibited substances listed by the World Anti-Doping Agency, we developed a certified reference material (CRM) for 3β,4α-dihydroxy-5α-androstan-17-one (DHAS), a metabolite of formestane that is used to conceal prohibited anabolic steroids, in methanol solution (NMIJ CRM 6212-a). To develop a CRM traceable to the International System of Units (SI), we newly applied different analytical methods with an SI-traceable internal standard for quantitative NMR (qNMR) instead of mass balance approach because this CRM solution was required to develop rapidly using a limited amount of high-purity DHAS. One method was gravimetric blending using the purity of DHAS powder evaluated by both qNMR and a combination of qNMR and high-performance liquid chromatography (HPLC), and the other was direct quantification of the DHAS mass fraction in the candidate solution CRM by both qNMR and qNMR/HPLC. Because the values obtained by gravimetric blending and direct quantification of the mass fraction were comparable, the arithmetic mean was applied to obtain the certified value. Considering homogeneity and stability according to ISO Guide 35: 2017, the certified values with expanded uncertainties (coverage factor k = 2, approximate 95% confidence interval) were (135.2 ± 9.5) μg/g for the mass fraction and (107.0 ± 7.5) μg/ml for the mass concentration.

Synthesis of highly porous layered hydrogen titanium oxide(HTO) granule by using carboxymethylated cellulose nanofibrils(CMCNFs) for effective recovery of Lithium(Li) from low-grade brines

Layered hydrogen titanium oxide (HTO) shows potential for lithium (Li) recovery from low-grade brines, but its practical use is hindered due to its particulate nature. In this study, we developed highly porous HTO granules using carboxymethylated cellulose nanofibrils (CMCNFs) as a binder (CMCNF@HTOs) and evaluated their Li adsorption efficiency in simulated brines. These granules were produced by combining a 5 wt% CMCNF solution with varying HTO powder weight ratios, followed by freeze-drying and thermal cross-linking. Optimal conditions yielded granules with over 93.48 % mechanical stability and more than 51.22 % porosity, using a 10:1 CMCNF solution to HTO powder ratio. The HTO powder is homogeneously distributed on the granules with 66.60 % of contents.The CMCNF@HTO demonstrated a maximum Li adsorption capacity of 34.72 mg/g, only a 6.77 mg/g reduction compared to pure HTO powder (41.49 mg/g). This minimal decrease in capacity is attributed to the granules' highly porous structure from freeze-drying and the hydrophilic properties of CMCNFs, which mitigated the brine diffusion interference. Furthermore, the effectiveness of CMCNF@HTOs was tested in various simulated brines, including those from the Salton Sea, saline groundwater, and the Great Salt Lake. Notably, in each brine, the CMCNF@HTOs selectively recovered only Li, underscoring their practicality for Li extraction from diverse low-grade brine sources.

The Characterization of a Biodegradable Mg Alloy after Powder Bed Fusion with Laser Beam/Metal Processing for Custom Shaped Implants.

A new Mg-Zn-Zr-Ca alloy in a powder state, intended to be used for custom shaped implants, was obtained via a mechanical alloying method from pure elemental powder. Further, the obtained powder alloy was processed by a PBF-LB/M (powder bed fusion with laser beam/of metal) procedure to obtain additive manufactured samples for small biodegradable implants. A series of microstructural, mechanical and corrosion analyses were performed. The SEM (scanning electron microscopy) analysis of the powder alloy revealed a good dimensional homogeneity, with a uniform colour, no agglutination and almost rounded particles, suitable for the powder bed fusion procedure. Further, the PBF-LB/M samples revealed a robust and unbreakable morphology, with a suitable porosity (that can reproduce that of cortical bone) and without an undesirable balling effect. The tested Young's modulus of the PBF-LB/M samples, which was 42 GPa, is close to that of cortical bone, 30 GPa. The corrosion tests that were performed in PBS (Phosphate-buffered saline) solution, with three different pH values, show that the corrosion parameters have a satisfactory evolution comparative to the commercial ZK 60 alloy.

Additive Manufacturing of TiC/Steel Composites Using Electron Beam Melting and In Situ Infiltration

Cemented carbides containing titanium carbide (TiC), characterized by low specific weight, superior hardness, and excellent high‐temperature resistance, are widely used as wear‐resistant cutting tools and brake discs. Instead of using conventional powder metallurgical approaches, composites comprising TiC and stainless steel are fabricated in this study by means of an innovative method combining electron beam powder bed fusion (PBF‐EB) and in situ liquid metal infiltration. For PBF‐EB, a pure TiC powder as feedstock and a stainless steel plate as substrate are used, respectively. Owing to the high processing temperature in the hatching area, the TiC particles are inhomogeneously sintered. Simultaneously, an in situ infiltration of liquid steel into the pores between TiC particles takes place during PBF‐EB, forming a dense and crack‐free composite material containing ≈68% TiC. The electrical properties of the raw TiC powder are investigated at different temperatures to optimize the process parameters ensuring high process stability during PBF‐EB. The microstructure and mechanical properties (compression strength, hardness, and fracture toughness) of the PBF‐EB‐produced TiC/steel composite are analyzed.

Characterization of Pure and Doped ZnO Nanostructured Powders elaborated in Solar Reactor

The synthesis of nano-oxides is an important field of nanotechnology, as these materials possess unique properties and applications. Several methods have been developed for synthesizing nano-oxides, each offering advantages and disadvantages depending on the desired material characteristics. Solar energy focused on solar reactors can be utilized for nano-oxide elaboration, offering a sustainable and environmentally friendly approach. The current article presents the research carried out for the elaboration of pure and doped nanostructured zinc oxides using solar energy. The morphostructural characteristics were determined by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and the Brunauer-Emmett-Teller method. The attenuated total reflectance Fourier transform infrared spectroscopy confirmed the synthesis of pure and doped nanostructured ZnO. The optical properties were highlighted by UV-VIS Spectroscopy. The research points out that crystallite sizes vary between 37 and 51 nm due to the influence of doping metal. The morphology associated with these particles is predominantly whiskers with elongated parts between 0.18 and 1.4 um. Doping with Fe, Si, Yb, and Ce causes a wider band gap compared to pure ZnO nanoparticles. As solar energy becomes more accessible and efficient, solar-driven synthesis of pure and doped ZnO is poised to be a crucial factor in shaping the future of material science and technology.

A sustainable and energy efficient approach for development of electrically conductive materials and their characterizations

In this study, composite castings of electrically conductive materials were prepared using electromagnetic energy of frequency 2.45 GHz. Three separate sets of castings were produced inside the domestic microwave applicator cavity, with reinforced compositions of up to 15% in steps of 5% for each composite cast (copper (Cu) + 5% molybdenum (Mo), Cu + 10% Mo, and Cu + 15% Mo). A microwave radiation exposure time of 12 min was required for the complete melting of pure copper powder. However, the addition of Mo reinforcement caused a reduction in exposure time to 11.33 min (min) for the Cu-15% Mo composite cast. The formation of different phases was revealed by the X-ray diffraction analysis of the cast samples. Only a 0.92% copper oxide phase was detected in the pure copper cast samples. The composite cast samples exhibited peaks corresponding to Cu64O, Cu6Mo5O18, and MoO2. Microstructure analysis demonstrated that the grains grew in an equiaxed manner with a uniform dispersion of the reinforcements. The maximum microhardness achieved is 99.2 ± 4.99 Hv for Cu + 15% Mo which is 1.66 times better than microwave-cast copper sample.

Estimation of Lexisinatide in Bulk and Tablets by RP‐UPLC Method Developed by Quality by Design Concept

AbstractThe primary goal of the proposed study is to establish and validate a low‐cost, sensitive, reliable, and trouble‐free RP‐UPLC process with improved performance for the direct estimation of Lixisenatide in pure powder and fixed‐dose tablet form. The proposed method is optimized by implementing quality by design studies. The method is optimized using quadratic model of central composite design (CCD) of randomized response surface study. Successful separation of Lixisenatide is obtained by the use of Phenyl‐XBD (1.7 µm, 2.1 mm × 100 mm) column and a mobile phase of acetonitrile: 0.1% w/v OPA (60:40) with 0.5 mL min−1 flow rate. The separated Lixisenatide and its degradants are explorated with PDA detector which has the ability to provide comprehensive spectral information, rapid data acquisition, quantitative analysis, and peak purity analysis of all compounds simultaneously. The RT of Lixisenatide is found to be 1.34 min. The lowest concentration of Lixisenatide's limit of detection and limit of quantification makes guarantees regarding the method's sensitivity. For the provided range of linear concentrations (1.25–7.5 µg mL−1), the regression coefficient is found to be 0.999. The computed average percentage recoveries of Lixisenatide in spiked solutions ranged from 98.9% to 101.2%. The % degradation of Lixisenatide in the presence of a variety of forced conditions confirms the existing method's stability. Lixisenatide is significantly photo sensitive when compared to other stressful conditions such as acid, base hydrolysis, and oxidation. The proposed UPLC approach separates Lixisenatide with high sensitivity, a short retention time, and an affordable solvent system.

Optimizing microwave-assisted synthesis of akermanite nanoparticles using citric acid as a chelating agent: A combined machine learning and experimental approach

This study aims to synthesize akermanite (Ca2MgSi2O7) using an eco-friendly and fast microwave-assisted method and understand the effect of using citric acid (CA) as a chelating agent to optimize the calcination temperature for synthesizing pure akermanite nanoparticles (along with a trace amount of merwinite) at low calcination temperatures. This study developed a new predictive model by machine learning-assisted modeling to advance the understanding of relationship between synthesis parameters and the resulting purity and particle size of akermanite. To evaluate the reliability of the developed model in predicting the purity and characteristics of the resultant Ak powder, the crystallization behavior and phase formation sequence of citric acid-containing samples and those without citric acid were experimentally investigated by differential thermal analysis (DTA) and X-ray diffraction (XRD) techniques. Following validation and training, the developed model indicates promising effects of citric acid on reducing crystallization temperature, enhancing purity, and decreasing particle size. The synthesized powders were further characterized by field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDS), and transmission electron microscopy (TEM) analyses. For the first time, our results addressed the microwave-assisted synthesis as an effective method via experimental evidence and machine learning-assisted modeling that allows for the production of akermanite containing a trace amount of merwinite with the aid of citric acid at a relatively low calcination temperature of 950 °C. In vitro bioactivity evaluation supported the potential suitability of Ak powders for bone tissue engineering applications.

Characterisation of laser-cladded 410 stainless steel for in situ repair of turbine blade

Laser cladding was employed to apply a pure nickel powder coating onto 410 stainless steel turbine blade material, utilising a 50 W pulsed diode fibre laser system. Various process parameters were explored, including average laser power (20 W, 30 W, 40 W) and scanning speeds (SSs) (0.5 mm/s, 1 mm/s, 1.5 mm/s). The pulse width and frequency were fixed to 110 ns and 50 kHz, respectively. Successful deposition of nickel powder was accomplished at an average power of 40 W at various SSs. The microstructure, phase components, clad geometry, tensile properties, and microhardness of cladded specimens were examined. The experimental results show that the cladding layer has a metallurgical bonding with the substrate, having a visual interface with no cracks or defects. The clad layer's height peaked at 1 mm/s (175.889 μm), while the maximum clad depth occurred at 0.5 mm/s (367.797 μm). Predominant intermetallic phases observed included FeNi3, Cr1.36Fe0.52, along with fine carbides (M3C, M7C3, M23C6 where M – Fe, Ni). Enhanced mechanical properties were observed in the cladded samples compared to the substrate. At 1 mm/s SS, the clad zone exhibited the highest microhardness (221.4 HV), tensile strength (482.03 MPa), and Young's modulus (17.97 GPa).

Detection of Adulterants Metanil Yellow in Turmeric Powder Using Fourier Transform Infrared (FTIR) Spectroscopy Combined with Chemometrics OPLS-DA and PLS

Turmeric powder (Curcuma longa L.) is often used for food coloring and flavoring. The high demand for turmeric powder has led to adulteration, one of which is metanil yellow. This study aims to detect metanil yellow dye in turmeric powder using Infrared Spectroscopy (FT-IR) and Chemometrics. The chemometrics model was built by preparing turmeric powder and metanil yellow in the concentration range of 0-50% (w/w). Data was processed using multivariate calibration using OPLS-DA (Orthogonal Partial Least Squares Discriminant Analysis) and PLS (Partial Last Square). The results obtained from OPLS-DA processing of market samples 1 and 2 are estimated to be pure turmeric powder, and samples 3 to 10 are adulterated. From the PLS results, the best calibration model was obtained at wave numbers 1199-539 cm-1 with R2 values for calibration and validation of 0.9967 and 0.9970, respectively, with RMSEC of 2.48 and RMSEP of 6.35. The PLS results showed that in sample 3 containing metanil yellow, in samples 4 to 10, no metanil yellow was detected. The ingredients added were not metanil yellow. It was concluded that FTIR combined with chemometrics could detect the metanil yellow in turmeric powder.

Studying the Effectiveness of Shaped Charge Jets Created by Graphene-containing Shaped Charge Liners

The paper presents selected results of studies conducted within the framework of the following research project: “Use of graphene and new multilayer explosive technologies in materials for shaped charge liners" (The National Centre for Research and Development in Poland: project No: DOB-BI08/03/01/2016). This study was performed by a consortium made up of the following entities: Institute of Precision Mechanics, Military University of Technology and the Mototechnika company (Poland). The main objective of the performed experiments was to test the effectiveness of shaped charge liners produced with the use of powder metallurgy methods, from mixtures containing copper powder and graphene-coated copper powder. The content of the latter equaled 0%, 1%, 5% and 10%, respectively. Shaped charge jets created with the use of liners made from the powder mixtures tested were recorded with the help of X-ray technology. Firing tests were conducted against steel barriers and the depth of penetration was determined. The obtained results showed that the addition of graphene powder to pure copper powder practically does not increase the depth of penetration of the shaped charge jet compared to scenarios in which sintered liners without this additive were used.

Production and Characterization of Ni0.50 Al0.50 and Ni0.55 Al0.45 Powders by Volume Combustion Synthesis

Nickel aluminide (NiAl) is an essential intermetallic material with a high melting point and excellent high temperature corrosion resistance. It is a solid solution of Ni and Al in 40-61 mol.% Ni range. In this study, Ni0.50Al0.50 and Ni0.55Al0.45 powders were formed by using nickel and aluminum elemental powders through volume combustion synthesis (VCS). MgO powder was utilized as the thermal diluent. According to adiabatic temperature calculations, MgO was added to the reactant mixture in 10-40 vol.% range for preventing the melting and sintering of the formed Ni0.50Al0.50 and Ni0.55Al0.45 particles. After VCS, the products were ground into powder form and leached in 3M HCl solution in order to remove the MgO particles. After VCS, the samples which were obtained with 10 - 30 vol.% MgO addition were quite hard and difficult to grind. This indicated the partial sintering of the formed particles. It was relatively easier to grind into powder form the samples which contained 40 vol.% MgO. Therefore, it was determined that the most suitable MgO ratio for the formation of Ni0.50Al0.50 and Ni0.55Al0.45 powders was 40 vol.%. Formed powders were mostly in 5-100 µm particle size range. The formation of single phase pure powders was confirmed by the XRD analyses. A shift of about 0.1 degrees to higher 2-theta values was determined in the XRD peaks of the Ni0.55Al0.45 powder as compared to the Ni0.50Al0.50 phase, after annealing the powders. The results were in agreement with the crystallographic data.