Particle Size Of Powder Research Articles

Optimization of formulation and device design for carrier-based nasal powder of influenza vaccine to maximize the delivery capability to the target site in the nasal cavity

Previously, a nasal powder formulation of the influenza vaccine was proposed to ensure its stability over fifteen months at room temperature and to have sufficient moisture-resistant characteristics to enable handling without special humidity control. In this study, a carrier-based concept: a physical mixture of the antigen powder and the carrier powder, was adopted for this nasal powder formulation. The physical properties of both components were optimized to maximize the delivery capability to the target site located behind the nasal cavity using a human nasal cast model. Preliminary evaluation with a prototype device (Device A) revealed that the physical properties of the antigen powder influenced the delivery efficiency mainly through their effect on the discharge rate from the device. Since it is obvious that the discharge rate from the device must be secured as a prerequisite for increasing the target site delivery, Device B with an improved discharge rate was developed, and the optimal powder properties were re-evaluated. The delivery rate of antigen powder to the target site was broken down into two elements: the discharge rate from the device and the delivery efficiency of emitted powder to the target site, and then the effect of the particle size of antigen powder and the carrier powder on each element was analyzed separately. As a result, an optimal particle size region was identified for each element as a design space on a two-dimensional map described by the antigen particle size and the carrier particle size. Besides this analysis, the fine particle fraction (aerodynamic particle size less than 5 μm) was evaluated in a separate experiment considering the risk of invasion into the lung and a condition of particle size to minimize the fine particle fraction was identified. By integrating the results of the above analysis, an optimal space was determined on the two-dimensional map to maximize the delivery efficiency to the target site while minimizing unintended exposure to the lungs.

State-enhanced attention network for optimisation of energy and yield in gas atomised metal powder production

Gas atomisation is a widely used technique for producing spherical metal powder feedstock for additive manufacturing. However, the process parameters suffer from variability and inefficiency in balancing powder yield, energy consumption, and particle size distribution. Optimising these complex, interdependent parameters pose a significant challenge. This work proposes a novel State-Enhanced Attention Network architecture in a framework that simultaneously optimises yield and energy consumption during nitrogen gas atomisation for sustainable metal powder production. The novelty lies in integrating processed long-term memory states with the attention mechanism, enabling nuanced attention weighting. This allows the model to leverage global sequence context and recent state information for improved yield and energy predictions. The proposed network is trained and integrated into a non-dominated sorting genetic algorithm to enable multi-objective optimisation. This framework evolves a set of Pareto-optimal solutions that balance trade-offs between maximising yield and minimising energy consumption. The approach is evaluated using augmented real-world data from an industrial gas atomisation plant. The proposed model demonstrates significantly improved predictive accuracy on real-world datasets, compared with baseline deep learning models. Results highlight the capabilities of the proposed technique for automated, data-driven optimisation of gas atomisation, simultaneously improving yield, energy efficiency, quality control, and sustainability. The integrated deep learning and evolutionary optimisation framework also provides an innovative solution for enhanced control of additive manufacturing powder production processes.

Stability and Rheological Properties of Grouts with Waste Glass Powder as Cement Replacement: Influences of Content and Alkali Activator.

Effective recycling and utilization of waste glass is a critical issue that urgently needs to be addressed. This study aims to explore the feasibility of using ground waste glass powder (particle size ≤ 75 μm) as a supplementary cementitious material to partially replace cement in the preparation of low-carbon and environmentally friendly grouting materials. The research systematically evaluates the impact of waste glass powder (WGP) on the fresh properties (particularly the stability and rheological characteristics) of cement-based grouting materials under various conditions, including WGP content (0-40%), the addition of NaOH activator (Na2O content of 4%) or not, and water-solid ratio (w/s = 0.5, 0.65, 0.8, 1.0). The results indicate that, in the absence of activator, the addition of WGP generally increases the amount of free liquid exudation in the grout, reducing its stability; however, under low w/s ratios, appropriate amounts of WGP can enhance stability. When the w/s ratio is high and the WGP content is large, the grout stability decreases significantly. The addition of NaOH activator (Na2O content of 4%) significantly reduces free liquid exudation, enhancing the stability of the grout, especially when the w/s ratio is less than 1.0. Furthermore, the Herschel-Bulkley Model was experimentally validated to accurately describe the rheological behavior of waste glass-cement slurries, with all R2 values exceeding 0.99. WGP and alkaline activator have significant effects on the rheological properties of the grout. Although they do not change its flow pattern, they significantly affect shear stress and viscosity. The viscosity of the slurry is influenced by the combined effects of w/s ratio, WGP content, and alkaline activator, with complex interactions among the three. The application of these research findings in the field of grouting engineering not only contributes to significantly reducing glass waste but also promotes the production of sustainable cement-based composites, lowering carbon dioxide emissions by reducing cement usage, and thereby alleviating environmental burdens.

Characterization of Spray-Dried Powders Using a Coated Alberta Idealized Nasal Inlet.

Background: Dry powders offer the potential to increase stability and reduce cold-chain requirements associated with the distribution of vaccines and other thermally sensitive products. The Alberta Idealized Nasal Inlet (AINI) is a representative geometry for in vitro characterization of nasal products that may prove useful in examining intranasal delivery of powders. Methods: Spray-dried trehalose powders were loaded at 10, 20, and 40 mg doses into active single-dose devices. Primary particle sizes (∼Dv50 = 10 µm for powder A and 25 µm for powder B), and sizes dispersed by devices, were evaluated using laser diffraction. The interior of the AINI was coated with a glycerol-surfactant mixture to mitigate particle bounce, and flow rates of 7.5 or 15 L/min were drawn through the AINI. Deposition of trehalose powder was determined in the four regions of the AINI (vestibule, turbinates, olfactory, and nasopharynx), a downstream preseparator, and an absolute filter (representing in vitro lung deposition) using liquid chromatography coupled with mass spectrometry. Results: Coating the AINI was effective in mitigating particle bounce for both trehalose powders. No difference in regional nasal deposition was observed when testing at a flow rate of 7.5 versus 15 L/min. A high fraction of both powders penetrated past the vestibule and deposited in the turbinates and nasopharynx for all loaded doses. For powder A, a non-negligible fraction of the recovered dose (up to 7%) is deposited on the filter, representing potential lung exposure. Conversely, a negligible fraction of the total recovered dose was deposited on the filter for powder B. Conclusion: Powders with a larger primary particle size showed reduced penetration through the nasal airways while maintaining high turbinate deposition. Optimized spray-dried powders offer the potential to target delivery to the peripheral nasal airways based on powder particle size while reducing lung exposure.

Investigation on the Thermal Decomposition Behavior of Molybdenum Trioxide Precursor.

The ultrafine MoO3 powders were prepared by the combination of centrifugal spray drying and calcination in this work. The thermal decomposition behavior of the spherical precursor was studied. The phase constituents, morphologies, particle size, and specific surface areas of MoO3 powders were characterized at different temperatures. It is found that the decomposition of the precursor is subjected to five stages, and forms different intermediate products, including (NH4)8Mo10O34, (NH4)2Mo3O10, (NH4)2Mo4O13, h-MoO3, and the final product α-MoO3. Moreover, the decomposition rate equation is established based on the thermal decomposition kinetic parameters of the precursor. With an increase in decomposition temperature, the morphology changes from unclear boundary particles to dispersed flake particles, and the flaky particles exhibit larger sizes, higher crystallinity, and better dispersion, which can be attributed to the mass transfer of gaseous MoO3 products. Additionally, the MoO3 particle size decreases progressively, and the specific surface area increases and then decreases. At 500 °C, it can achieve ultrafine flaky MoO3 powder with the size of thick sheets, with a thickness of about 300 nm and a length of about 1-3 μm. This research can offer an innovative strategy for preparing ultrafine MoO3 powder.

Powder Bed Additive Manufacturing Using Machine Learning Algorithms for Multidisciplinary Applications: A Review and Outlook

Additive manufacturing overcomes the limitations associated with conventional processes, such as fabricating complex parts, material wastage, and a number of sequential operations. Powder-bed additives fall under the category of additive manufacturing process, which, in recent years, has captured the attention of researchers and scientists working in various fields of science and engineering. Production of powder bed additive manufacturing (PBAM) parts with consistent and predictable properties of powders used during the manufacturing process plays an important role in deciding printed parts' reliability in aeronautical, automobile, biomedical, and healthcare applications. In the PBAM process, the most commonly used powders are polymer, metal, and ceramic, which cannot be effectively used without understanding powder particles' physical, mechanical, and chemical properties. Several metallic powders like titanium, steel, copper, aluminum, and nickel, several polymer polyamides (nylon), polylactide, polycarbonate, glass-filled nylon, epoxy resins, etc., and the most commonly used ceramic powders like aluminum oxide (Al2O) and zirconium oxide (ZrO2) can be utilized depending upon the method being adopted during PBAM process. Adoption of some post-processing techniques for powder, such as grain refinement can also be employed to improve the physical or mechanical properties of powders used for the PBAM process. In this paper, the effect of powder parameters, such as particle size, shape, density, and reusing of powder, etc., on printed parts have been reviewed in detail using characterization techniques such as X-ray computed tomography, scanning electron microscopy, and X-ray photoelectron spectroscopy. This helps to understand the effect of particle size, shape, density, virgin and reused powders, etc., used during the PBAM process. This article has reviewed the selection of appropriate process parameters like laser power, scanning speed, hatch spacing, and layer thickness and their effects on various mechanical or physical properties, such as tensile strength, hardness, and the effect of porosity, along with the microstructure evolution. One of the drawbacks of additive manufacturing is the variability in the quality of printed parts, which can be eliminated by monitoring the process using machine learning techniques. Also, the prediction of the best combination of process parameters using some advanced machine learning algorithms (MLA), like random forest, k nearest neighbors, and support vector machine, can be effectively utilized to quantify the performance parameters in the PBAM process. Thus, implementing machine learning in the additive manufacturing process not only helps to learn the fundamentals but helps to identify, predict and help to make actionable recommendations that help optimize printed parts quality. The performance of various MLAs has been evaluated and compared for projecting future research directions and suggestions. In the last part of this article, multidisciplinary applications of the PBAM process have been reviewed in detail. Additive manufacturing processes carried out by using conventional machines, called hybrid additive manufacturing, have also been reviewed by discussing their methods and arrangements in detail.

Hot press sintering of Y2O3-Al2O3 glasses: Impact of particle size on thermal behaviour, sintering ability and mechanical properties of sintered bodies.

The impact of grinding on particle size, thermal behaviour, and sintering ability of yttrium aluminate glass microspheres with eutectic composition (76.8mol % Al2O3 and 23.2mol % Y2O3) was studied. The work was conducted with the aim of determining the optimal particle size and grinding conditions of glassy powder used for hot-pressing of ceramic and glass-ceramic materials with desired mechanical properties. The flame synthesis was used for the preparation of glass microspheres (diameter∼40μm). Ball milling procedure under different conditions was applied to adjust of size of prepared microbodies. The milled powders were subsequently hot pressed. The prepared samples (raw, milled microspheres and hot-press sintered bodies were characterised by X-ray powder diffraction, and scanning electron microscopy. Thermal analysis and particle size analysis in combination with X-ray powder diffraction and high temperature X-ray diffraction was used for detailed inspection of thermal behaviour and phase changes in raw and milled systems in the temperature interval 25-1200°C. The samples after flame synthesis and after milling were found to be X-ray amorphous. The particle size measurements showed that the systems with a smaller average size D [0.9]∼25μm and a monomodal particle size distribution were prepared after 6h of milling. Thermal analysis in combination with X-ray and high temperature X-ray analysis indicated a difference in the crystallization mechanism of the yttrium aluminate garnet phase depending on the milling time. The bulk glass ceramic with fine lamellar eutectic microstructure and interesting mechanical properties (Vickers hardness HV=17.6±0.2GPa, indentation fracture toughness KIC=4.3±0.3MPa.m1/2) resulted from the sintering of microspheres milled for 6h under the "gentlest" conditions (milling speed - 200rpm, and milling balls size - 5mm in diameter).

Laser induced oxidation Raman spectroscopy as an analysis tool for iridium-based oxygen evolution catalysts.

The study of degradation behavior of electrocatalysts in an industrial context calls for rapid and efficient analysis methods. Optical methods like Raman spectroscopy fulfil these requirements and are thus predestined for this purpose. However, the iridium utilized in proton exchange membrane electrolysis (PEMEL) is Raman inactive in its metallic state. This work demonstrates the high oxidation sensitivity of iridium and its utilization in analysis of catalyst materials. Laser induced oxidation Raman spectroscopy (LIORS) is established as a novel method for qualitative, chemical and structural analysis of iridium catalysts. Differences in particle sizes of iridium powders drastically change oxidation sensitivity. Oxidation of the iridium powders to IrO2 occurred at a laser power density of 0.47 ± 0.06 mW μm-2 for the 850 μm powder and at 0.12 ± 0.06 mW μm-2 and 0.019 ± 0.015 mW μm-2 for the 50 μm and 0.7-0.9 μm powders respectively. LIORS was utilized to assess possible deterioration of an iridium electrocatalyst due to operation under electrolysis. The operating electrocatalyst exhibited higher oxidation sensitivity, suggesting smaller iridium particle size due to catalyst dissolution. Peak shifts of the IrO2 signal were utilized to assess differences in transformation temperatures. The operated electrocatalyst transformed to IrO2 at lower temperature (8 cm-1 redshift) relative to the pristine catalyst (10 cm-1 redshift), demonstrating that pre-oxidation of the iridium to amorphous IrOx during electrolysis diminishes the energy barrier needed for IrO2 formation. Thus, LIORS can be utilized as a straightforward screening method for the analysis of iridium electrocatalysts in the industrial application of PEMEL.

Synthesis of reusable cement materials through photochemical modification of marble powder for composite structures.

Sustainability and environmental protection are reshaping industries, including construction, where sustainability plays a crucial role in its influence on global resource consumption and waste management. The current study has developed a reusable cement material by photo-chemical surface modification of marble powder, achieved by reacting glycidyl methacrylate with carbonate functionality. This innovative modified marble powder boosts the reusability of construction materials, unlocking new possibilities for sustainable building practices. By transforming waste into valuable resources, we minimize raw material consumption, foster recycling, and advance circular economy principles in the construction industry. The difference in unmodified (22.9nm) and modified (23-27nm) marble powder particle sizes was used to assess the effectiveness of surface modification technique. Compared to non-reusable counterpart (20.34MPa), the reusability has come at the cost of a decrease in compression stress (11.30MPa, 10.89MPa, and 10.57MPa). Overall, photochemically modified marble powder for its reusability is a groundbreaking approach that offers substantial environmental, economical, and technical advantages, making it an appealing choice for the construction industry.

RADIO-ABSORBING MATERIALS BASED ON GRAPHITE PARTICLES IN EPOXY RESIN

This paper presents the results of a study on radio-absorbing materials in the ultra-high frequency range of 78-118 GHz. Crystalline graphite powder (particle size 0.1 mm) was considered as the main radio-absorbing material. Epoxy resin was used as a substrate and a binder. The samples were prepared by dispersing the graphite powder across the surface of the epoxy resin substrate. The most effective working thickness of epoxy resin has been established experimentally. The geometric dimensions of the arrangement of the installation components at which the most effective signal recording is observed are calculated. The results of the studies showed that a film consisting of graphite particles on the surface of epoxy resin effectively shields radio emissions in the 3-millimeter range.

High Speed Sintering of Polyamide 12: From Powder to Part Properties.

High Speed Sintering (HSS) is an additive manufacturing process with great potential to produce complex, high-quality polymer parts on an industrial scale. However, little information is currently available on the characteristics of the powder materials used and the part properties that can be achieved. This is also the case for the standard material polyamide 12 (PA 12) and the first commercially available HSS machine, the VX200 HSS. The aim of this study is, therefore, to provide the first comprehensive overview of the properties of PA 12 parts manufactured with the VX200 HSS and the characteristics of the PA 12 powder. This includes the analysis of the influence of part orientation and part position in the build job. To characterize the powder, particle size distribution, particle shape, thermal properties and powder flowability were analyzed. To characterize the parts, density and various thermal, mechanical and geometrical properties were analyzed. In summary, the powder material and part properties are largely similar to those of other Powder Bed Fusion of Polymer (PBF/P) processes. However, there are also significant differences for some part properties. It was also determined that the anisotropy of parts is very low compared to that of many other additive manufacturing processes.

Research on the Construction of Coal Powder Settling Final Velocity Model for Coalbed Methane Wells in Panhe Block

ABSTRACTIn response to the severe problem of coal powder production in the Panhe block coalbed methane wells in the southern Qinshui Basin, the characteristics of coal powder production in the study area were identified through sample testing, indoor experiments, and theoretical calculations. The settling velocity of coal powder with different mesh sizes was clarified, and a correction factor α was proposed for the experimental and theoretical results of settling velocity. The research results indicate that the coal powder concentration in the Panhe block ranges from 0.03 to 7.14 g/L, with an average of 1.26 g/L. The particle size of the coal powder produced was 4.10–237.64 μm, with an average of 35.82 μm. The settling velocity of coal powder particles with a mesh size of 40–400 is between 0.0041 and 0.029 m/s. The larger the particle size of coal powder particles, the higher the settling velocity of coal powder; the correction coefficient ranges from 2.3 to 13.67. A corrected settling velocity calculation model was obtained by fitting the coal powder particle size data to the correction coefficient. The research results provide a theoretical basis for developing production conditions, coal powder prevention, and control measures for coalbed methane wells in the Panhe area.

Effect of aluminum powder particle size on quasi-static pressure and temperature in confined space explosion of aluminized explosives

Abstract Aluminum powder particle size is a crucial parameter concerning the energy release of aluminized explosives. This study aimed to examine the effect of single aluminum powder particle size and particle size gradation on the explosive energy release characteristics of aluminized explosives in confined spaces by using a self-developed confined explosion experimental device. Aluminized explosive samples having aluminum powder particle sizes of 6, 24, and 43 μm and particle size gradation of 6/24/43 μm were tested for explosion parameters generated by an internal explosion. The results indicate that the quasistatic pressure of the measured aluminum powder samples decreased gradually with the increase of the particle size. The quasi-static pressure of the particle size gradation explosive samples was the largest, and the quasi-static pressure increased by 5.0%, 9.9%, and 12.0%, respectively, compared with a single particle size. The highest peak temperature was observed for the 6 μm particle size sample. However, the highest equilibrium temperature was obtained for the particle size gradation sample, indicating that particle size gradation promotes the reaction of aluminum powder in the afterburning stage; this helps maintain the temperature of a confined space for a certain duration and increase the energy release of the aluminized explosives.

Effect of powder particle size on the microscopic morphology and mechanical properties of 316 L stainless steel hollow spheres

Effect of powder particle size on the microscopic morphology and mechanical properties of 316 L stainless steel hollow spheres

Bandwidth expansion effects and electromagnetic wave loss mechanisms in Y2Co8Fe9 powders with multiple particle size distributions

Electromagnetic interference and radiation demand advanced absorbing materials to moderate pollution. In this work, the wide bandwidth and strong absorption electromagnetic wave absorbing material Y2Co8Fe9 powder was prepared by the plasma-assisted ball milling method, and the microstructure and electromagnetic wave absorption mechanism were systematically investigated. The particle size of Y2Co8Fe9 powder was optimized to enhance absorption properties, resulting in a minimum reflection loss of −41.4 dB after 2 h of ball milling, with an effective absorption bandwidth (EAB) of 7.6 GHz at a thickness of 1.6 mm. The concept of average loss is introduced based on the synergistic effect of dielectric and magnetic losses. It is demonstrated that an average loss within 0.45 leads to desirable EAB values. These results demonstrate the significance of determining the influence of particle size distributions and average losses on material absorption performance, providing an innovative perspective to preparing efficient wave-absorbing materials.

Experimental Study on the Influence of Rotational Speed on Grinding Efficiency for the Vertical Stirred Mill

The rotational speed of the agitator is one of the important parameters that affect the grinding efficiency of the vertical stirred mill. Increasing the speed will improve the grinding effect, but it will increase energy consumption, and determining a reasonable speed setting is a system issue. The effects of different speeds on energy consumption, product particle size, and grinding efficiency were analyzed in this study. An experimental vertical stirred mill was used to grind iron ore, and five different speed parameters from 175 rpm to 350 rpm were set as variables. It was found that increasing the rotational speed will increase the grinding effect, but it will trigger more energy consumption. A new evaluation index to comprehensively reflect the grinding efficiency of the mill, which was defined as the ability of a mill to grind the same product per unit of time and energy consumption, was proposed. The grinding efficiency was calculated when the particle size of iron ore powder decreased to −45, −38, and −28 μm at different speeds. It can be seen that the growth rate of energy consumption is faster than that of the percentage of particle size, which leads to a continuous decrease in grinding efficiency with the increase in rotational speed. If high processing capacity is pursued within a certain period of time, high speed can be chosen, but it will result in energy loss. On the contrary, the low speed can be chosen, if considering grinding economy.

The Influence of Different Butter Type, Their Fatty Acid Composition and Melting Enthalpy on the Viability Rate of Lacticaseibacillusrhamnosus GG Directly After the Spray-Drying Process and During Storage of Powders.

The present work reports on the microencapsulation of Lacticaseibacillus rhamnosus GG (LGG) by the spray-drying process using a solution of starch, whey protein concentrate (WPC), soy lecithin and ascorbic acid as a carrier, with addition of different types of butters. The aim of this study was to examine the protective mechanism of six different butter samples on the viability rate of LGG bacteria directly after the spray-drying process and during storage for 4 weeks at 4 °C and 20 °C (±1 °C) based on hypothetical factors-the fatty acid's chemical character and content, and its melting enthalpy. The viability of bacteria, moisture content, water activity, color properties, morphology, particle size of powder, melting enthalpy of butters and their fatty acids composition were evaluated. It is assumed that the highest viability may be indirectly influenced by the relationship between the highest content of proteins and sugars and the lowest content of fats and fatty acids, which is characteristic for butter with a reduced fat content. This butter contained also the least monounsaturated and polyunsaturated fatty acids. The highest number of viable LGG (for systems with reduced-fat butter, as well as salted and lactose-free butter) may be caused by (among other factors) by the lower content of palmitic acid (C16: 0). For these butters, it was also observed that cell viability increased with the increase in melting enthalpy. The results confirmed the protective role of selected butters, which indicates the possibility of using them in industrial processes to increase the durability of additives and products using probiotic powders obtained by spray-drying.

Microstructure and ablation resistance of C/C-HfC-SiC composites prepared by RMI with different powder particle sizes

To improve the ablation and scouring resistance of C/C composites, powder with particle sizes of 0.5–1 μm, 1–3 μm and 10–20 μm were used as infiltration powder to prepare C/C-HfC-SiC composites, named HSV-0.5-1, HSV-1-3 and HSV-10-20, respectively. Results show that the agglomeration of the powder makes it difficult to form a uniform and dense ceramic layer on the sample surface. The content of HfC ceramics increases with the particle size of the initial powder. In addition, the grain size of HfC first increases and then becomes irregularly spherical as the initial powder particle size increases. After ablation for 40s, HSV-1-3 shows the best resistance to ablation due to the mixed crystal form of flakes and spheres that form a denser oxide film in the center of the ablation. In three subsequent room-temperature airflow scour tests, the oxide film of HSV-1-3 and HSV-10-20 were damaged in the sample surface. After following ablation for 40 s, HSV-10-20 showed good ablation resistance with the linear ablation of −0.75 μm/s. The reason is the high HfC content and dense ceramic layer contribute to the formation of a continuous and complete oxide layer that prevents oxygen diffusion during ablation. This work provides guidance on the use of particle size in the RMI.

A comparative study of thermal sprayed Al2O3-TiO2 coatings on PM AISI 316L

The widespread use of stainless steels (SS) in various applications is hindered by their inadequate wear resistance, hardness and high density. Structural metallic components fabricated via powder metallurgy (PM) exhibit lower densities compared to those produced by conventional methods due to their inherent high porosity. However, this compromises their mechanical and corrosion performance. This study has investigated the application of pure Al2O3 and Al2O3 + 13 %TiO2 powders with varying particle sizes on PM AISI 316L substrates to enhance their mechanical and wear properties. The phase composition, microhardness, coating morphology, surface roughness, porosity and wear rate of coated and uncoated samples were comparatively analysed to elucidate the influence of both TiO2 addition and coating powder particle size on the mechanical properties and surface morphology of the samples. Microstructural and XRD studies confirmed good mechanical and metallurgical bonding of the coatings to the substrate. All of the coated samples exhibited 24 to 34 times higher surface roughness and 1.3 to 2.1 times lower porosity values compared to the substrate. The finer sized TiO2 added alumina-based coating powder reduced the surface roughness and porosity value to 1.8 and 1.4 times respectively while the use of the coarser sized one reduced these values to 1.3 and 1.2 times respectively compared to the pure Al2O3 coated surface. 8-times higher hardness and 70-times lower wear rate values compared to the substrate were the most significant improvements observed in the pure Al2O3 coated surface among all coated samples. Although TiO2 addition to the coating powder decreased hardness by 1.1 times and increased wear rate by 1.8 times, spraying finer TiO2 added coating powders resulted in a slight improvement in both hardness and wear resistance compared to the coarser one.

Low-temperature preparation of nano-sized Al2TiO5 powder via non-hydrolytic sol-gel route with Al metal as the aluminum source

Al2TiO5 powder was prepared using the non-hydrolytic sol-gel route, with Al powder and titanium tetrachloride as precursor materials. The synthesized powder was characterized via XRD, DSC-TG, TEM, FTIR, FE-SEM, and laser particle size analyzer. The results indicated that Al2TiO5 powder can be synthesized at 750 ℃ via gelation when the aluminum-to-alcohol molar ratio was 1:14 and titanium tetrachloride concentration was 0.9 mol/L. The average particle size of Al2TiO5 powder was 80 nm using reflux gelation and 35 nm with direct drying gelation. The Al metal utilized the hydrogen chloride produced in situ to activate itself and formed Al-O-Ti hetero-bonds through non-hydrolytic polycondensation. The Al-O-Ti hetero-bonds underwent an exothermic reaction at around 695 ℃ to form Al2TiO5. This research has broadened the range of precursor materials available for preparing Al2TiO5 using the non-hydrolytic sol-gel route.