Processing, microstructure and mechanical properties of magnesium matrix nanocomposites fabricated by semisolid stirring assisted ultrasonic vibration

Nie, Kai-bo; Wang, Xiaojun; Wu, Kun; Xu, Lijuan; Zheng, M.Y.; Hu, X.S.

doi:10.1016/j.jallcom.2011.06.091

Cited by 107 publications

(56 citation statements)

References 25 publications

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“…However, when the stirring time was increased to 120 min, the mean particle size of NPs was seen to increase to 489.70±1.71 nm. Nie and co-workers [29] demonstrated that an increase in the stirring time encourages agglomeration and particle growth, resulting in an increased mean particle size. The effects of different volume ratios of CS to TPP ranging from 25:5 to 25:15 on the physicochemical properties of CS-NPs are shown in fig.…”

Section: Particle Size Pdi and Zeta Potentialmentioning

confidence: 99%

Self-Assembled Chitosan Nanoparticles for Percutaneous Delivery of Caffeine: Preparation, Characterization and in Vitro Release Studies

et al. 2018

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Objective: Chitosan (CS)-tripolyphosphate (TPP)-nanoparticles (NPs) have been extensively studied during the past few decades due to their wellrecognized applicability in various fields. The present study attempts to optimise the development of these nanoparticles to enhance the percutaneous delivery of caffeine.Methods: CS-TPP-NPs were prepared via ionic cross-linking of CS and TPP and were characterized. The influence of several formulation conditions (CS: TPP mass ratio and concentration of caffeine) and process parameters (stirring speed, stirring time and ultra-sonication time) on the colloidal characteristics of CS-TPP-NPs were investigated and the resulting nanoparticles were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) and x-ray diffraction (XRD) analyses. Physicochemical properties, including particle size, zeta potential and polydispersity index (PDI) were examined, and in vitro release studies were conducted to ascertain the release profile of caffeine from the nanoparticles. In addition, the colloidal stability of the prepared NPs was also assessed on storage.Results: Process parameters appeared to exert a significant effect on the physicochemical characteristics of the CS-TPP-NPs. The CS-TPP-NPs prepared under optimum conditions (CS concentration of 0.2 mg/ml, CS: TPP volume ratio of 25:12 ml, stirred at 700 rpm for 60 min, with 0.97 mg/ml caffeine concentration and treatment with low ultra-sonication for 30 min) had shown a mean particle size of ~143.43±1.69 nm, zeta potential of+43.13±1.10 mV, PDI of ~0.30±0.01. A drug loading capacity and encapsulation efficiency of 48.89% and 60.69%, respectively, were obtained. Cumulative release study for drug-loaded CS-NPs was significantly (p<0.001, paired t-test) higher (58.7% caffeine released) compared to control formulation (41.5% caffeine released) after 72 h. Stability studies conducted for 28 d showed that caffeine-loaded CS-NPs degraded much quicker when stored at 25 ⁰C than 4 ⁰C. It was also noted that caffeine-loaded CS-NPs in the freeze-dried form were unstable as the surface charge of nanoparticles dropped from positive zeta potential to-3.55 mV within 2 d at 4 ⁰C and at 25 ⁰C, surface charge dropped to-3.16 mV within 14 d of the experiment. Conclusion:Chitosan (CS)-tripolyphosphate (TPP)-nanoparticles (NPs) appear to be a promising strategy to achieve sustained percutaneous delivery of caffeine.

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Section: Particle Size Pdi and Zeta Potentialmentioning

confidence: 99%

Self-Assembled Chitosan Nanoparticles for Percutaneous Delivery of Caffeine: Preparation, Characterization and in Vitro Release Studies

et al. 2018

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“…Compared with traditional micron-sized SiC p /Al composites, the higher tensile strength and good ductility of the nano-sized SiC p /Al composites entitle them to have more competitive ability for advanced structural applications such as in automotive and aerospace industries and the military [10]. In the past decades, several processing techniques have been developed for fabricating Al matrix composites reinforced with nano-sized particles such as high-energy milling, powder metallurgy, and nano-sintering, and liquid-state solidification processing (e.g., stir casting) [11][12][13][14][15][16][17][18][19]. In these techniques, the semisolid stirring process has some important advantages such as low cost, capability of producing products with complex shapes, and processing simplicity [14].…”

Section: Introductionmentioning

confidence: 99%

Microstructures and Tensile Properties of Al–Cu Matrix Composites Reinforced with Nano-Sized SiCp Fabricated by Semisolid Stirring Process

Qiu

Gao

Tang

et al. 2017

Metals

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Abstract:The nano-sized SiC p /Al-Cu composites were successfully fabricated by combining semisolid stirring with ball milling technology. Microstructures were examined by an olympus optical microscope (OM), field emission scanning electron microscope (FESEM) and transmission electron microscope (TEM). Tensile properties were studied at room temperature. The results show that the α-Al dendrites of the composites were strongly refined, especially in the composite with 3 wt. % nano-sized SiC p , of which the morphology of the α-Al changes from 200 µm dendritic crystal to 90 µm much finer equiaxial grain. The strength and ductility of the composites are improved synchronously with the addition of nano-sized SiC p particles. The as-cast 3 wt. % nano-sized SiC p /Al-Cu composite displays the best tensile properties, i.e., the yield strength, ultimate tensile strength (UTS) and fracture strain increase from 175 MPa, 310 MPa and 4.1% of the as-cast Al-Cu alloy to 220 MPa, 410 MPa and 6.3%, respectively. The significant improvement in the tensile properties of the composites is mainly due to the refinement of the α-Al dendrites, nano-sized SiC p strengthening, and good interface combination between the SiC p and Al-Cu alloys.

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“…In rheocasting, incorporation of nanoparticles is done in the semisolid state of a matrix. A combination of techniques such as semisolid processing (stirring) assisted by ultrasonic vibration has been utilized to achieve effective dispersion when using nano-reinforcements (Nie et al 2011;Kandemir et al 2012). …”

Section: Semisolid State Processesmentioning

confidence: 99%

Light Metal Matrix Composites

Jayalakshmi¹,

Gupta

2015

SpringerBriefs in Materials

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Fundamentals of metal matrix composites are overviewed. The various light metal matrix systems (particularly Al and Mg) and the different types of reinforcements used are mentioned. The various composite production methods are described. Strengthening mechanisms that define the enhancement in properties of composites are discussed. The microstructural and mechanical properties of the composites are summarized. In addition, the several disadvantages encountered in MMCs due to ceramic reinforcement addition are understood from interfacial characteristic/properties. Keywords

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Processing, microstructure and mechanical properties of magnesium matrix nanocomposites fabricated by semisolid stirring assisted ultrasonic vibration

Cited by 107 publications

References 25 publications

Self-Assembled Chitosan Nanoparticles for Percutaneous Delivery of Caffeine: Preparation, Characterization and in Vitro Release Studies

Self-Assembled Chitosan Nanoparticles for Percutaneous Delivery of Caffeine: Preparation, Characterization and in Vitro Release Studies

Microstructures and Tensile Properties of Al–Cu Matrix Composites Reinforced with Nano-Sized SiCp Fabricated by Semisolid Stirring Process

Light Metal Matrix Composites

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