Mica Powder Research Articles

A fluorine-free bioinspired multifunctional slippery coating for ultra-long-term anticorrosion of Mg alloy, static/dynamic anti-icing, antibacterial and antifouling

Poor corrosion resistance limits the application of Mg alloy and it is meaningful to explore a surface coating technology for ultra-long-term corrosion protection of Mg alloy. Superhydrophobic surface (SHS) and smooth liquid-injected porous surface (SLIPS) have shown important application value in the field of Mg alloy corrosion protection. However, the unstable special interface of air layer or lubricant cannot act as stable corrosion barrier for the long term. Inspired by frog skin, a bionic fluorine-free multifunctional slippery coating (MSC) is prepared by one-step spraying a mixture of epoxy resin, silicone oil, modified nano TiO2 and modified micron mica powder. MSC exhibits a microstructure similar to frog skin, excellent slippery (sliding angle ∼ 3°) and strong lubricant retention. Different from anticorrosion mechanism of SHS and SLIPS by their special interface, MSC, storing silicone oil on the surface and inside the coating, demonstrates ultra-long-term anticorrosion to Mg alloy (both neutral salt spray and 3.5 wt% NaCl solution immersion for 60 days) due to excellent barrier effect throughout coating, and the scratch defect area of MSC is not significantly eroded after 14 days of salt spray. Moreover, MSC exhibits excellent static/dynamic anti-icing ability and low ice adhesion in a −20℃ environment, outstanding adhesion (level 4B), high hardness (3H), antibacterial (>94 %), antifouling, chemical stability and resistance to boiling water, ice water and UV radiation. All these excellent properties can promote the application of Mg alloy in a wider range of fields.

Effect of silane coupling agent on mechanical properties, flame retardancy, and ceramifiable behavior of ceramifiable flame‐retardant silicone rubber composite

AbstractIn order to improve the dispersibility of inorganic fillers and enhance its ceramifiable flame‐retardant efficiency, the ceramifiable flame‐retardant silicone rubber composites were prepared using glass powder, zinc borate, ammonium polyphosphate, mica powder, platinum catalyst as ceramifiable flame‐retardant agent, and various silane coupling agents as interfacial modifier. The micromorphology, mechanical properties, flame retardancy, thermal stability, and combustion behavior of ceramifiable flame‐retardant silicone rubber composites, as well as the flexural strength of the corresponding ceramics generated after pyrolysis of the composites were examined. The results reveal that the inclusion of silane coupling agents improves the dispersibility of ceramifiable flame‐retardant agents substantially. The mechanical properties, flame retardancy, thermal stability, and combustion behavior of ceramifiable flame‐retardant silicone rubber composites are all improved. When compared to a composite without a silane coupling agent, the tensile strength of the composite can be improved by up to 1.9 times. Only 0.5phr silane coupling agent is required to raise the vertical combustion rating from V‐1 to V‐0, and the composite with 3 phr KH570 has a LOI value of 38.6. Meanwhile, the heat release rate of the composite is reduced to a certain extent, and the time to ignition and residue are dramatically enhanced after the addition of silane coupling agent in the cone calorimetry test. Moreover, flexural strength of the corresponding ceramics generated after pyrolysis of the composites rapidly increases with increasing silane coupling agent content, which can reach to 24.7 MPa with addition of 3 phr KH570.

Experimental study on freeze-thaw resistance of mortar: An attempt to modify hydrophobic materials with hydrophobic nano-silica

In this study, a novel superhydrophobic additive (MPSANS) was developed to enhance the freeze-thaw (F-T) resistance of mortar by modifying mica powder with stearic acid and hydrophobic nano-silica. Firstly, the effects of hydrophobic nano-silica content on the hydrophobic properties of MPSANS modified mortar were studied, and MPSA10NS5 exhibited the best hydrophobic property, the water absorption and water desorption of modified mortar decreased by 65.42 % and 35.84 %, respectively. On this basis, abundant tests were conducted to analyze the effects of MPSA10NS5 content on the F-T resistance of mortar. Analytical findings suggested that MPSA10NS5 noticeably reduced the loss of relative dynamic modulus of elasticity and compressive strength of mortar. Furthermore, the microstructure was determined by using the scanning electron microscopy and mercury intrusion porosimetry. According to the test results, MPSA10NS5 refined the pore structure inside mortar and inhibited the crack development. Meanwhile, MPSA10NS5 effectively reduced the most probable aperture of mortar, resulting in an increase of harmless pores and a decrease of harmful pores.

Ultrafine grinding of mica in organic medium for ink-jet printing process

This work investigates the grinding of a mica powder in an organic medium in order to make the particle size compatible with the inkjet process using a high-energy ball mill. A detailed protocol leading to size reduction without altering structural properties of interest of this material has been successfully developed. Two steps are necessary, namely dry grinding and wet grinding in ethanol. The final particle size obtained was D90 = 1.9μm which is very close to the size requirement of the inkjet process related to the printing nozzle diameter (52μm). The mica morphology in the form of platelets was shown to be conserved by means of scanning electron microscope observations. X-ray diffraction confirmed that the mica did not undergo any change in its crystallographic structure. The decrease in particle size was revealed by the broadening and intensity drop of the diffraction peaks. Thermogravimetric analyses highlighted a shift of dehydroxylation reactions towards lower temperatures, which is also coherent with platelet size reduction.

Corrosion resistance of powder metallurgy fabricated Cu–10Sn/SiC/mica hybrid composite

Abstract For the first time, bronze/SiC/mica hybrid composite has been manufactured using powder metallurgy method. Mixture – process variable design has been applied to design of experiments and optimization of the composite composition, as well as the production process variables (compaction pressure and sintering temperature) to attain superior corrosion resistance. This involved mixing different compositions of bronze, SiC, and mica powders, which were subsequently subjected to varied pressures and temperatures during the pressing and sintering stages, all in accordance with the experimental design plan. The microstructure, chemical composition, and elemental distribution of the samples were examined using scanning electron microscope equipped by energy dispersive X-ray analyzer, and an optical microscope. In order to study the corrosion resistance, potentiodynamic polarization test and electrochemical impedance spectroscopy were performed in 3.5 wt.% NaCl solution. The results revealed that co-incorporation of SiC and mica particles in Cu–10Sn bronze matrix increases the corrosion resistance, with a synergistic effect between these particles. The result of optimization process showed that the highest corrosion resistance could be achieved for the composite with the composition of Cu–10Sn/9.85SiC/0.67mica. This outcome was subsequently validated through experimental procedures.

VO2 nano-rod coated mica composite pearlescent pigment for temperature control packaging

A temperature control mica/VO2 functional pearlescent pigment was designed for the packaging industry. Firstly, a layer of VO2 nanorod film was coated on the surface of flake mica powder by hydrothermal method. Then, the surface of pure mica was modified by silane coupling agent KH-570 and sandwiched between inorganic powders to strengthen the combination. Secondly, the mica/VO2 composite pearlescent powder with gray-green pearlescent effect were successfully obtained by thermal annealing. The crystal structure of the VO2 coating and the chemical valence state of vanadium were verified by X-ray diffraction and X-ray photoelectron spectroscopy. Finally, powders were mixed with polyurethane resin to obtain a functional film. The infrared transmittance of film at 28 °C and 70 °C showed that the composite film with mica content of 3 g had greater temperature control properties, and the difference between high and low temperature transmittance was about 16%. Most importantly, the shiny decorative effect of pearlescent pigment can be still be maintained after being endowed with temperature control property. This work proposes the preparation of functional mica/VO2 composite with pearlescent effect and temperature control property.

Evaluation of Pozzolanic activity and lime reactivity of fly ash, GGBS, mica powder and pumice as binders

This article presents the effect of the pozzolanic activity and lime reactivity of various siliceous materials, like fly ash, GGBS (Ground granulated blast furnace slag), mica and pumice powders. The pozzolanic activity is evaluated as per ASTM and lime reactivity test as per IS 1727. Based on the ASTM C311 tests, at 28 days GGBS, pumice and fly ash showed 71%,12% and 9% improvement in strength respectively in comparison with the control mix for 20% replacement of binder. Mica powder showed decrease of strength in comparison with the control mix. It has been observed that all binders satisfy the criteria of requirement of strength as per ASTM C311 activity index which is greater than 0.75. Based on the lime reactivity tests carried out as per IS 1727 carried out, maximum lime reactivity has been observed in case of GGBS (26%), followed by fly ash (25%), pumice (9%) and mica powder (8%) in comparison with the control mix with 20% replacement of hydrated lime.

Engineering geological characterization of micaceous residual soils considering effects of mica content and particle breakage

The engineering geological characteristics of micaceous residual soil (MRS), which is prevalent in subtropical regions, are markedly influenced by the presence and breakage of mica particles. Nevertheless, a comprehensive understanding of the underlying mechanisms responsible for these effects remains elusive. In this study, a series of experimental tests were conducted on two groups of reconstituted MRS samples. These samples were prepared by mixing natural MRS, from which the original mica had been removed, with intact and crushed mica powder, respectively. The aim was to investigate the effect of the mica content and particle breakage on the physical and mechanical properties of MRS. Scanning electron microscopy was employed to scrutinize the microstructural alternations of mica particles at different states of breakage, and a conceptual model was proposed based on the observations. The findings revealed that the presence of mica considerably altered the physical properties of MRS, resulting in higher Atterberg limits but lower plasticity, along with unfavorable mechanical properties, including high compressibility and swelling potential, low compactability, stiffness, strength, and ductility. The microstructural analysis elucidates that these effects stem from the resilient nature of layered mica flakes with high water-retention capacity. On the other hand, the breakage of mica particles changed these effects. The disappearance of interlayered voids following mica particle breakage leads to reduced Atterberg limits and enhanced compaction efficiency of the mixture. Moreover, MRS with a higher proportion of crushed mica exhibited more significant deformation and compression during shearing. This behavior can be attributed to the diminished stiffness of crushed mica and weaker interparticle contacts within the soil matrix. This study provided a multi-scale insight into how mica affected the engineering geological properties of MRS and proposes references for more effectively incorporating of MRS into engineering construction projects.

A Comparative Pharmaceutical Study of Abhrasindoora by Traditional and Contemporary Method

Background: Rasashastra is a Pharmacotherapeutics of Mercurial, Metallic, and Mineral preparations Abhrasindoora (AS) is a unique Herbo-Metallic-Mineral Compound, which is mainly indicated in respiratory diseases. Method: AS contains Dhanyabhraka (Bio-purified Black Mica Powder), Shodhita Parada (Bio-purified Mercury), and Shodhita Gandhaka (Bio-purified Sulphur) in equal proportion. These mixtures were subjected to trituration in Kharal till Kajjali formation (ABS-72 hrs) followed by impregnation of latex of Arka (Calotropis procera linn) (QS) (16 hrs) and Vatashunga (Ficus benghalensis linn) (QS) (15 hrs). Then Batch-A & Batch-B were prepared separately in Valuka Yantra and Electric Muffle furnace by maintaining mild (150 0C-250 0C), (150 0C - 300 0C) moderate (250 0C -400 0C), (300 0C -450 0C) and intense temperature (400 0C - 550 0C), (450 0C -650 0C) respectively. Observation: Batch A AS was prepared in 37 hours and the total yield of the product obtained was 54 grams. Batch B AS was prepared in 21 hours and the total yield of the product obtained was 25 grams. Jet black colour Kajjali of AS turned to dark red which was sublimated at the neck of Kachkupi. Conclusion: The yield of Batch A was more than Batch B but it took more time. Hence, the preparation of Kupipakva Rasayana in a sand bath should be done repeatedly to conclude it is a more economic and convenient process.

Development of a hydrophobic cement mortar with controllable strength: Preparation and micro-mechanism analysis

The widespread utilization of hydrophobic concrete in applications is often hindered by the significant decrease in mechanical properties observed when traditional modifiers are added to cement mortars. To address this issue, the present study introduces a novel hydrophobic additive called modified mica powder (MMAP). This additive has been developed specifically to enhance the water and corrosion resistances of cement mortar. To determine the optimal mix ratio, the effects of modifiers, particle sizes of MAP, and various preparation methods of MMAP were investigated. These parameters were analyzed in relation to the mechanical properties and water absorption characteristics of the MMAP modified cement mortar. As a result of the experiments, it was found that the capillary water absorption of the MMAP modified cement mortars was reduced by 23.5%-64.4% in comparison to that of the unmodified ones. More importantly, the MMAP had no adverse effect on the mechanical properties of the cement mortar, which was superior to that of the MAP addition using conventional methods. furthermore, the microscopic characteristics of both MMAP and MMAP modified cement mortar were examined using techniques such as FTIR, SEM, and EDS. Through these analyses, insights into the hydrophobic mechanism of the MMAP modified cement mortar were obtained, shedding light on the underlying processes and interactions responsible for its enhanced water resistance properties.

Development of exfoliated mica waste/natural rubber composites by latex stage mixing

ABSTRACT Raw mica powder may not show better physico-mechanical properties in rubber owing to its large particle sizes and low degree of surface activeness. Here, mica waste; a green filler was modified by partially exfoliating before incorporating it into natural rubber (NR). The latex stage mixing was conducted to incorporate different loadings of exfoliated mica waste (eWM). The incorporation of eWM had no significant effect on cure and scorch time. The reduction of viscosities indicated better processability of the compounds. The overall improvement of moduli, tensile, abrasion resistance, and cross-link densities supported by SEM and TGA data suggested improved rubber–filler interactions.

Formulation and Performance of NBR/CR-Based High-Damping Rubber Composites for Soundproof Using Orthogonal Test.

Multiple functional-material-filled nitrile butadiene rubber/chloroprene rubber (NBR/CR) acoustic composites were extensively studied and prepared. According to the orthogonal test table L25 (56), 25 groups of samples were prepared by using a low-temperature one-time rubber mixing process. With tensile strength, average transmission loss, and damping peak as indexes, the influence degree of different factors and levels on the properties of acoustic composites was quantitatively discussed and analyzed. The matrix weight analysis was employed to optimize the material formula of rubber composites, and the corresponding influence weight was given. Results showed that the acoustic composite with blending ratio of 70/30 for NBR/CR matrix had preferable mechanical and acoustic properties; adding mica powder (MP) and montmorillonite (MMT) in matrix contributed to improve all above three indexes owing to their specific lamellar structures; hollow glass beads (HGB) had a positive influence on improving acoustic property due to its hollow microcavities, however, it had a negative impact on damping property because of the smooth spherical surfaces. Accordingly, the optimal formulation was found to be NBR/CR blending ratio of 70/30, MP of 10 phr (per hundred rubber), HGB of 4 phr, and MMT of 10 phr.

Impact of mica on geotechnical behavior of weathered granitic soil using macro and micro investigations

The micaceous weathered granitic soil (WGS) is frequently encountered in civil engineering worldwide, unfortunately little information is available regarding how mica affects the physico-mechanical behaviors of WGS. This study prepares reconstituted WGS with different mica contents by removing natural mica in the WGS, and then mixes it with commercial mica powders. The geotechnical behavior as well as the microstructures of the mixtures are characterized. The addition of mica enables the physical indices of WGS to be specific combinations of coarser gradation and high permeability but high Atterberg limits. However, high mica content in WGS was found to be associated with undesirable mechanical properties, including increased compressibility, disintegration, and swelling potential, as well as poor compactability and low effective frictional angle. Microstructural analysis indicates that the influence of mica on the responses of mixtures originates from the intrinsic nature of mica as well as the particle packing being formed within WGS. Mica exists in the mixture as stacks of plates that form a spongy structure with high compressibility and swelling potential. Pores among the plates give the soil high water retention and high Atterberg limits. Large pores are also generated by soil particles with bridging packing, which enhances the permeability and water-soil interactions upon immersion. This study provides a micro-level understanding of how mica dominates the behavior of WGS and provides new insights into the effective stabilization and improvement of micaceous soils.

Physical properties of natural rubber latex foams produced with processed mica waste powder and creamed natural rubber latex

Incorporation of finely powdered mica waste into natural rubber latex processed into foam rubber, consuming a minimum amount of energy could contribute to progress towards a greener environment. In this study, mica waste generated in the mining industry was finely powdered and incorporated into creamed natural rubber latex which is an alternative form of concentrated latex manufactured using a green process known as the creaming process. Finely powdered processed mica waste (PMW) was added as a filler into latex varying the loading from 0 to 10 pphr at 2 pphr intervals. The latex foam was then converted into a vulcanized natural rubber latex foam (NRLF). Effects of mica loading on certain properties of the foam rubber produced from creamed natural rubber latex were studied. It was found that the density and hardness of the mica powder incorporated foam rubber increased with increasing filler loading. Fourier transformed infrared spectroscopy (FTIR) studies confirmed that no structural changes occurred in natural rubber due to the addition of PMW. The overall results of the study showed the potential of utilization of mica waste and creamed natural rubber latex to manufacture greener natural rubber foam composites in cottage-level foam manufacturing industries.

Thermal insulation and structural reliability of modified epoxy resin‐based ablation thermal protection coatings in aerothermal‐vibration coupling environment

AbstractNovel hybrid ablation thermal protection coatings (FHMP‐ATPCs), employing iron trioxide (Fe2O3) powder, hollow glass microspheres, and mica powder as the fillers in hydroxyl‐terminated silicone oligomer‐bridged epoxy resins (PSG) copolymer, is investigated using an aerothermal‐vibration coupling test system. The ablation behavior and structural reliability of FHMP‐ATPCs with varying coating thickness were studied. During the test, the total enthalpy of airflow and dynamic pressures are 23 MJ/kg and 300 Pa, accompanied by the random vibration with a frequency of 20–2000 Hz and a total root‐mean‐square acceleration of 14.9g. The maximum surface and back‐face temperatures of the coating with the thickness of 2 mm reached 836.2°C and 156.4°C, respectively. Results also showed that the reduction of thickness obviously suppressed the surface temperature and increase in back‐face temperature yet maintaining high structural reliability. Compared with DGEBA‐based coatings, the PSG‐based coatings showed excellent structural reliability during the test. The study provides a solution for obtaining high performance ATPCs, which are highly desired for supersonic vehicles.

Preparation and characterization of solvent-free anti-corrosion polyurethane-urea coatings

Metal corrosion can cause severe damage to metal facilities, leading to huge economic loss. Anti-corrosion coating is considered to be effective and economic for the protection of metal facilities. Herein, a series of polyurethane-urea coatings were prepared with aromatic isocyanate, amino terminated polyether, castor oil-based polyol and polyaspartic resin as reactants and conductive mica powders as filler. The effect of isocyanate index on the chemical structure, static conductivity and corrosion resistance of the polyurethane-urea coatings were studied, and the micromorphology of the coating layers were observed. With the increase of isocyanate index, the cross-linking degree of the coating increased, while the compactness and electrostatic conductivity decreased, which was caused by the generation of carbon dioxide bubbles in the coating layer. Electrochemical impedance spectroscopy and salt spray test indicated that as the isocyanate index increased, the anti-corrosion ability of the polyurethane-urea coating on the flawless area increased, but that on the defect area decreased. The polyurethane-urea coatings prepared with isocyanate index of 1.0-1.1 possessed good corrosion resistance and electrostatic conductivity. The findings conceivably provided a new strategy to prepare solvent-free anti-corrosion coatings for the protection of metal and metallic facilities and promote the rapid development and practical application of anticorrosive materials.

Hybrid Bisphenol A non-isocyanate polyurethane composite with Mica powder: A new insulating material

Non-isocyanate polyurethanes (NIPU) or hydroxyurethanes from CO2 sourced monomers were prepared via a non-toxic route, which avoided the toxic isocyanate utilization with an excellent conversion ratio of cyclic carbonate, higher than 95%. The hybrid NIPU was prepared in the presence of aminosilylated-mica, used as reinforcement to improve mechanical properties, besides keeping the charge dissipation. The improvement of mechanical, thermal and electrical properties by silylated mica is attributed to higher crosslinking density in the organosilicate network. (attributed to the interfacial urethane linkage between the -NH2 on the surface of the mica and the cyclocarbonates). It has been demonstrated the feasibility to produce candidate materials for replacing epoxy-mica paper hybrid system by an alternative CO2 derived non-isocyanate hydroxyurethane-mica powder system. This system holds two advantages: CO2 long-term capture and a more simplified hybrid formation, since no vacuum pressure impregnation (VPI) is necessary, does resulting on lower energy consumption.

NBR/CR‐Based High‐Damping Rubber Composites Containing Multiscale Structures for Tailoring Sound Insulation

AbstractHigh‐damping acoustic composites with unique sound insulation feature is reported, demonstrating surprisingly stable soundproof properties over a wide bandwidth of frequency (63–6300 Hz) with good mechanical properties. The extraordinary acoustic properties are attributed to the multiscale synergy of lamellar and hollow structures by multifillers adding. The acoustic composites are designed and fabricated through a low‐temperature one‐time rubber mixing process using nitrile butadiene rubber(NBR), chloroprene rubber (CR) as matrix and mica powder (MP), hollow glass beads (HGB), and montmorillonite (MMT) as multifillers. The soundproof mechanism is discussed in detail. Results indicate that the synergism of damping and sound absorption behaviors in the composition has a considerable impact on the acoustic characteristics, which can be controlled by the blending ratio of NBR/CR matrixes and the multiscale structures of MP/HGB/MMT multifillers. The designed multifillers acoustic composites can adapt to broadband engineering noise control including walls in express train constructions, panels of vessel or aircraft cabins, and large transportation pipelines.

Thermal insulation and anti-vibration properties evaluation of modified epoxy resin-based thermal protection coatings in arc-jet

Thermal protection system (TPS) is crucial for hypersonic flight vehicles to effectively protect them against the aerothermal effect imposed on them during flying with high Mach number. A novel hybrid ablation thermal protection coatings (FHMP-ATPCs) on the surface of stainless steel substrate were prepared by doping iron trioxide (Fe2O3) powder, hollow glass microspheres (HGM) and mica powder (MP) into hydroxyl-terminated silicone oligomer-bridged epoxy resins (PSG) copolymer. The thermal insulation and structural reliability of the FHMP-ATPCs were investigated by a novel aerothermal-vibration coupling test system. During the test, the heat flux of the surface of coatings ranged from 400 kW/m2 to 700 kW/m2. Meanwhile, the vibration load was a random vibration with frequency range of 20–2000 Hz and root mean square of total acceleration (Grms) of 10.8 g. The maximum surface and back-face temperature reached 714.9 °C and 141.3 °C, respectively. Compared with epoxy resin based coatings，the PSG-based coatings showed excellent structural reliability during the test. This study demonstrates the robust effect of strategy of modifying epoxy resin with organosilicon in improving thermal insulation performance yet maintaining the structural reliability of the ablation thermal protection coatings, providing a promising route to achieve high-performance coatings.

Recycling of isabgol (Plantago ovata Forsk.) straw biomass and mineral powder with bio-inoculants as an effective soil amendment for isabgol cultivation

Efficient utilization of isabgol ( Plantgo ovata Forsk.) straw biomass through preparation of bio-active organic fertilizer in a natural composting process has not been studied. In this study, phosphate rock and silicate mineral (mica) powder were used as natural sources of phosphorus (P) and potassium (K), respectively. Cow dung slurry as a natural decomposer was mixed with the straw biomass at a 10:1 (weight/weight) ratio along with mineral powder. Then, nutrient-mobilizing bio-inoculants were used in the composting process after attaining thermal stabilization. The agronomic effectiveness of the resulting bio-active compost (BAC) as a bio-organic fertilizer was compared with that of conventional organics (farmyard manure and vermicompost) and chemical fertilizer (CF) by growing isabgol under field conditions. Composting with the natural sources of P and K along with the bio-inoculants increased the total nitrogen (13.6 g kg -1 ), P (38.7 g kg -1 ), and K (31.2 g kg -1 ) contents in the final product ( i.e ., BAC) compared with composting without the mineral powder and bio-inoculants. Application of BAC remarkably improved the seed yield (2.5%) and husk quality of isabgol in comparison with conventional organics and CF. Compared with CF, BAC significantly boosted the economic yield of isabgol by improving the husk recovery (2.5%) and mucilage yield (4.12%). Furthermore, BAC significantly improved the soil quality by increasing organic carbon (C), available nutrients, and microbial biomass C contents, as well as enzyme activity. The positive correlation between soil and plant parameters also highlighted the benefits of BAC for isabgol production through soil quality improvement. Therefore, it can be considered as a zero-waste technology, whereby a large quantity of straw biomass generated from isabgol cultivation, which contains essential nutrients, can be recycled back to the soil. Furthermore, BAC can be effectively used as a bio-active organic fertilizer, particularly in systems where chemical inputs are restricted, such as organic agriculture.