Aid Of Ultrasonic Vibration Research Articles

Diffused phase transition boosted dye degradation with Ba (ZrxTi1−x)O3 solid solutions through piezoelectric effect

Micron-sized Ba(Zr x Ti 1−x )O 3 particles have been prepared using the conventional solid state method, and their microstructure, morphology and piezocatalytic properties have been investigated in detail. The present study shows that Ba(Zr 0.05 Ti 0.95 )O 3 is a relaxor-like ferroelectric having a typical perovskite structure with existence of polar nanodomain regions at room temperature. With the increase of the degree of diffuseness γ, the piezoelectric properties increased. Also, the particles exhibit good piezocatalytic performance in degrading organic pollutants with the aid of ultrasonic vibration. The catalytic activity can be significantly improved by poling, i.e. the alignment of polarization using an applied electric field. The catalytic degradation ratio of RhB, MB and MO dyes for poled Ba(Zr 0.05 Ti 0.95 )O 3 particles is reached ~95%、~70% and ~65% after 90 min, respectively. Our results also reveal that the existence of polar nanodomain due to the diffuse phase transition can highly boost the catalytic activity of the Ba(Zr 0.05 Ti 0.95 )O 3 particles, which can be used as multifunctional catalyst for degrading organic pollutions. • The diffuse phase transition can enhance the piezocatalytic activity. • The polar nanodomains are responsible for high piezocatalytic performance. • The polar nanodomains can induce local polarization and inhomogeneity. • Micron-sized Ba(Zr 0.05 Ti 0.95 )O 3 particles display RhB degradation of 95%.

Investigation on sheet flexible-die drawing process

The characteristics of sheet flexible-die drawing process were discussed, compared with traditional sheet drawing process, sheet flexible-die drawing process can improve the limit drawing ratio, reduce the forming force, balance the thickness distribution and enhance the formability of the sheet. In this paper, the forming principle, research status and the forming characteristics of hydroforming, viscous pressure and solid granules sheet drawing process were demonstrated. In addition, the improvement of forming quality and efficiency under the aid of ultrasonic vibration, electricity, magnetic field and the mixture of them were also reviewed.

Experimental study on cutting force in ultrasonic vibration-assisted turning of 304 austenitic stainless steel

The generation mechanism of cutting force in ultrasonic vibration assisted turning (UAT), with the composition and decomposition of cutting force is discussed in this paper, and the model of cutting force in UAT is established based on the mechanism of UAT. The force measuring test system is designed on the basis of the established machining system of UAT. The contrast experiments for turning the workpiece of 304 austenitic stainless steel are conducted with and without ultrasonic vibration under different technological parameters. Furthermore, the relational model and correlation between technological parameters and cutting force is obtained by regression analysis and variance analysis. Thereby, the mutual relation among these technological parameters is effectively controlled, which contributes to achieving the high quality and high efficient processing. Simultaneously, the influences of single technological parameter with the interaction between technological parameters on cutting force are researched and analyzed. The results prove that the cutting force is reduced significantly with the aid of ultrasonic vibration in turning and the choice of the proper ultrasonic amplitude, there is an optimal range of ultrasonic amplitudes as well. Meanwhile, the cutting parameters have great influence on cutting force, among which depth of cut has the superior influence, then the cutting speed, and feed rate has the minimal influence. Moreover, cutting parameters should not be too large, UAT is mainly used for semi-finishing or finishing at medium-low speed. UAT will get more ideal machining effect if cutting parameters are chosen properly.

Research Status of Ultrasonic Vibration Assisted Plastic Forming Process

Ultrasonic vibration assisted plastic forming is a process method for assisting the forming of metal materials by means of ultrasonic vibration devices. It is proved that the ultrasonic vibration could reduce the forming force, improve the friction environment, and enhance the formability of the metal material. However, there are some differences in forming characteristics for different materials under different vibrational plastic forming processes. In this paper, the forming principles, the vibration application modes and the forming characteristics of the ultrasonic vibration assisted the wire drawing, equal channel angular pressing (ECAP), upsetting, drawing of the sheets and hydroforming of the tube are reviewed. It emphasizes on the various processes’ improvement of the forming efficiency and the quality of the formed parts under the aid of ultrasonic vibration. Finally, the future development trend of ultrasonic vibration assisted plastic forming was prospected.

Preparation of multifunctional PLZT nanowires and their applications in piezocatalysis and transparent flexible films

La-doped Pb(Zr,Ti)O3 (PLZT) has attracted great attentions because of their potential applications in sensors, energy devices and other fields. In this work, PLZT nanowires (NWs) were prepared by electrospinning and calcination processes. With the aid of ultrasonic vibration, the PLZT NWs can decompose 97% of methyl orange dye within 160 min. The rate constant k of degradation is as high as 0.02 min−1. The transparent composite films can be achieved by mixing PLZT NWs and polydimethylsiloxane with the assistance of dielectrophoresis. When the content of PLZT NWs is 3%, the transmittance of the film reaches to 92.4%. The composite film also shows a good property for harvesting mechanical energy. Taken advantages of the excellent performance, the PLZT NWs can be widely used in the fields of environment and energy.

Microstructures and mechanical properties of in-situ CaB6 ceramic particles reinforced Al-Cu-Mn composite

The properties of reinforcing particles, preparation technology and interfacial bonding between reinforcing particles and the matrix are crucial factors affecting the properties of particle-reinforced composites. In this paper, in-situ CaB6 nanoparticles were prepared by melt-spinning and CaB6/Al–Cu–Mn nanocomposites with uniform distribution of reinforcing particles in the matrix were prepared with the aid of ultrasonic vibration. The effects of CaB6 amounts on the microstructure and properties of the composites were studied. The distribution of CaB6 particles in the matrix was analyzed by SEM. The results indicated that the dispersibility of CaB6 nanoparticles in 1 vol.% and 2 vol.% CaB6/Al–Cu–Mn nanocomposites was better than that in 3 vol.% CaB6/Al–Cu–Mn nanocomposites. The CaB6/Al interface was studied by HRTEM and first-principles calculation. The results indicated that CaB6 and α-Al could form a coherent interface, and the interfacial energies of the CaB6/Al interfaces were very low. The CaB6 particles significantly improved the room and high temperature properties of the Al–Cu–Mn alloy.

Effect of ultrasonic vibration field on tungsten inert gas welding of magnesium alloy and galvanized steel

In this paper, the authors introduced ultrasonic vibration into the molten bath via ultrasonically vibrating welding wire and investigated the effect of ultrasonic vibration on the mechanical properties, microstructures and macrostructures of tungsten inert gas (TIG) welded AZ40 Mg alloy and DP780 galvanized steel joints. The main results are summarized as follows. During the ultrasonic vibration aided TIG welding, ultrasonic vibration can improve the wettability of welding pool on the steel plate and eventually increase the width of welding seam than that without ultrasonic vibration. The average grain size of fusion welding area is obviously reduced with the assistance of ultrasonic vibration and gives rise to the increase of micro hardness. A 4 μm thickness intermetallic compound layer occurs at the brazing area of joint and the ultrasonic vibration aided process has no obviously effect on the microstructure of brazing area of Mg/steel joint. The maximum tensile strength of Mg/steel workpiece increases 8.2% to 252 MPa over the workpiece welded without ultrasonic vibration, owing to the effective refinement strengthening. Besides, the fracture surface of Mg/steel workpiece obtained with the aid of ultrasonic vibration is characterized with more plastic fracture features.

A new laser joining technology for direct-bonding of metals and plastics

A direct laser joining technique for bonding plastics to metals, namely laser-assisted metal and plastic (LAMP) joining was developed about eight years ago. Notwithstanding the successes that have been obtained for LAMP, the inherent features of laser-induced bubbles in the joint remains a major concern. In this research, a new laser joining technology with the aid of ultrasonic vibration has been developed to bond plastics to metals with improved joint strength. Experiments have been conducted to join polyethylene terephthalate and titanium using this new technology; preliminary results have been encouraging. With the aid of ultrasonic vibration, joint strength can be improved by as much as four times greater than that produced by the conventional LAMP process. This improvement is largely caused by the formation of a thicker chemically bonded metal-plastic interface, which was supported by the results of an XPS analysis conducted across the joint interface.

A research on ultrasonic-assisted abrasive waterjet polishing of hard-brittle materials

In the present study, the abrasive waterjet (AWJ) with the aid of ultrasonic vibration was used to improve the processing performance of hard-brittle materials. The method is termed as the ultrasonic-assisted abrasive waterjet polishing (UA-AWJP). Aluminum nitride was chosen as the workpiece material. Ultrasonic vibration perpendicular to the jet impact direction was applied on the workpiece by using a specially designed stage. A series of experiments were performed to evaluate the performance of the UA-AWJP. The processing performances and the polished surface topographies of the AWJP and UA-AWJP were compared to investigate the effects of ultrasonic vibration. The results show that UA-AWJP has a higher processing efficiency than AWJP. The surface roughness of the polished surface was modeled. The model shows a considerable agreement with the experimental results. The experimental results show that a lower pressure, finer abrasives, and a smaller impact angle are ideal to obtain a high surface quality.

Effects of sonication on anticorrosive and mechanical properties of electrodeposited Ni–Zn–TiO2 nanocomposite coatings

Ni–Zn–TiO2 nanocomposite coating was fabricated using the electrodeposition process with the aid of ultrasonic vibration (0, 108, 135, 162 and 216Wcm−2 ultrasonic power densities) on mild steel disks. The properties of the nanocomposite film were investigated using scanning electron microscopy (SEM), energy dispersive X-ray (EDX), EDX-mapping, Vickers microhardness test, Tafel polarization test and electrochemical impedance spectroscopy (EIS). The results revealed a significant improvement of anticorrosive properties and hardness of the nanocomposite coatings compared to Ni–Zn alloy coating. Ecorr became more positive and changed from −0.921V for Ni–Zn alloy coating to −0.789V for Ni–Zn–TiO2 nanocomposite coating. Icorr decreased from 1.25×10−5Acm−2 for Ni–Zn alloy coating to 3.46×10−6Acm−2 for Ni–Zn–TiO2 nanocomposite coating. On the other hand, hardness increased from 253HV for Ni–Zn alloy coating to 876HV for Ni–Zn–TiO2 nanocomposite coating. The improvements were related not just to the content of nano-TiO2 in the coatings but also to surface homogeneity and nanoparticles uniform dispersion in the matrix of the coating.

Room-temperature bonding of heterogeneous materials for near-infrared image sensor

A room-temperature bonding technique using cone-shaped microbumps with the aid of ultrasonic vibration is applied to the fabrication of a near-infrared (NIR) image sensor. The image sensor is fabricated using the chip-on-chip integration of an InGaAs photodiode array on an InP substrate and a Si CMOS readout IC. The pixel pitch is 25 µm to compose quarter-VGA class (320 × 256 pixels) resolution. A high-quality imaging of a heated object is demonstrated. Bonding of the VGA array with 15 µm pitch is attempted to realize a high-resolution image sensor.

Ultrasonic brazing of magnesium alloy

Authors tried to braze magnesium alloy in air using no flux with the aid of ultrasonic vibration, and investigated the effect of brazing conditions on the joint properties. The main results obtained in this study are as follows. Applying ultrasonic vibration made it possible to braze the magnesium alloy in air without flux and the joint strength was so high that the joint fractured partially in the base metal. The brazing temperature at which solid and liquid phases coexisted in filler metal could provide the brazed joint with the maximum tensile strength. This seemed to be because the liquid phase in the filler metal infiltrated into the cracks occurring in the oxide film on the faying surface during heating and the solid phase would rub against the oxide film to detach, resulted in removing the oxide film from the faying surface. The optimal time for applying ultrasonic vibration could effectually detach and remove the oxide film from the faying surface. The excessive applying time of ultrasonic vibration caused defects such as cavity formation in the brazed layer and led to decrease the joint strength.

SiC nanoparticles reinforced magnesium matrix composites fabricated by ultrasonic method

SiC nanoparticles reinforced magnesium matrix composites were fabricated by ultrasonic method. The AZ91 alloy and SiC nanoparticles with the average diameter of 50 nm were used as the matrix alloy and the reinforcement, respectively. The addition of nanoparticles was 0.1%, 0.3%, and 0.5% (mass fraction) of the composites. The results of microstructural evaluation and mechanical properties indicate that the nanoparticles can be dispersed into magnesium alloys efficiently and uniformly with the aid of ultrasonic vibration. As compared with the matrix alloys, the grains of composites were refined and the mechanical properties of composites were improved significantly. The SEM and DSC analyses show that the SiC nanoparticles can act as the heterogeneous nucleation of a-Mg. Also, the strengthening mechanism responsible for the composites reinforced with SiC nanoparticles was discussed.

Ultrasonic assisted fabrication of particle reinforced bonds joining aluminum metal matrix composites

This paper presents a method of producing uniform particle strengthened bonds between pieces of aluminum metal matrix composite (Al-MMCs), of strength equal to that of the substrate material. SiC particle reinforced Zn-based filler metals were fabricated by mechanical stir casting and ultrasonic treatment, and then used to join pieces of SiC p/A356 composite with the aid of ultrasonic vibration. The filler metals made by mechanical stirring were porous and contained many particle clusters. Ultrasonic vibration was used to disperse the agglomerates and prevent further coagulation of SiC particles during joining, but the method failed to eliminate the porosity, resulting in a highly porous bond. The filler metal treated by ultrasonic vibration was free of defects and produced a non-porous bond strengthened with uniform particles between pieces of SiC p/A356 composite. The presence of surface oxide films at the bonding interface significantly degraded the performance of SiC particle reinforced bond. Removal of this oxide film by at least 4 s of ultrasonic vibration significantly increased the bond strength, reaching a value equal to that of the substrate metal.

Brazing of A5056 aluminium alloy with the aid of ultrasonic vibration using Ag filler metal

In order to produce a high strength brazed joint of A5056 aluminium alloy containing magnesium of about 5 mass%, the authors applied a flux-free brazing method with the aid of ultrasonic vibration to the aluminium alloy by selecting pure Ag foil as brazing filler metal and examined the effect of brazing conditions on the joint properties. The main results obtained in this study are as follows. At a brazing temperature of 570°C, just above the eutectic point of Al–Ag binary system, application of ultrasonic vibration for 4.0 s provided the brazed joint with the maximum tensile strength and the strength decreased with the application time. When the brazing temperature was varied from 550 to 580°C and the application time of ultrasonic vibration was kept constant at 4.0 s, the joint brazed at 560°C attained the maximum tensile strength and fractured in the base metal. It was found that using a pure Ag foil as brazing filler metal successfully brazed A5056 aluminium alloy and the joint strength was equivalent to that of the base metal. Fracture of the joint was prone to occur along the (Al3Mg2 + Al solid solution) phase with high hardness formed at the grain boundary of the base metal. The amount of the hard (Al3Mg2 + Al solid solution) phase increased with the ultrasonic application time and the brazing temperature. It seemed that the increase of the hard (Al3Mg2 + Al solid solution) phase mainly caused the brazed joint strength to decrease.

マグネシウム合金の超音波ろう付

Authors tried to braze magnesium alloy in air using no flux with the aid of ultrasonic vibration, and investigated the effect of brazing conditions on the joint properties. The main results obtained in this study are as follows.Applying ultrasonic vibration made it possible to braze the magnesium alloy in air without flux and the joint strength was so high that the joint fractured partially in the base metal. The brazing temperature at which solid and liquid phases coexisted in filler metal could provide the brazed joint with the maximum tensile strength. This seemed to be because the liquid phase in the filler metal infiltrated into the cracks occurred in the oxide film on the faying surface during heating and the solid phase would rub against the oxide film to detach, resulted in removing the oxide film from the faying surface. The optimal time for applying ultrasonic vibration could effectually detach and remove the oxide film from the faying surface. The excessive applying time of ultrasonic vibration caused defects such as cavity in the brazed layer and led to decrease the joint strength.

Performance of the polymer- and oxide-supported triphase catalysts and effect of ultrasound on their stabilities

Abstract In this study, several trialkylamines were immobilized on chloromethylated polystyrene (CMPS), silica gel, and alumina to prepare triphase catalysts for catalyzing the etherification reaction of allyl bromide (the organic reactant) and sodium phenolate (the aqueous reactant). The reactor was agitated mechanically or with the aid of ultrasonic vibration. Performances of the prepared catalysts were compared, and the effect of imposing ultrasound was investigated based on the activity, selectivity, and stability of the catalyst. Experimental results show that tri-n-propylamine is the best active species when CMPS is used as the support, while tri-n-butylamine is the best when SiO2 and Al2O3 are employed as the supports. The CMPS-supported catalyst is far better than the SiO2- and Al2O3-supported catalysts in activity and selectivity but not in stability. Imposing the ultrasound can effectively increase the reaction rate. Mechanical agitation at a low speed with the imposition of ultrasonic vibration not only results in a conversion slightly higher than the case with a high mechanical agitation speed without ultrasonic vibration, but also gives a constant stability for the CMPS-supported catalyst.

Environmental-benign methods for the color protection of stripe long-shoot bamboo ( Bambusa dolichoclada) culms

Fresh stripe long-shoot bamboo ( Bambusa dolichoclada Hayata) culm is attractive for its yellow and green stripes. The stripes, however, discolor quickly after harvest, and currently there is no method to preserve the colors. The objective of this study was to find methods to preserve the colorful yellow–green stripes. Results indicated that excellent color preservation was achieved by treating the bamboo culms with 1% copper nitrate in alcohol at 60 ∘ C for 2 h. Such treatment could be shortened to 30 min by the aid of ultrasonic vibration during the treatment. Immersing bamboo culms in 1% copper nitrate alcohol solution at the ambient temperature for 4 h also achieved the same result. Treated specimens exhibited outstanding colorfastness and mildew resistance after 18 months of indoor exposure.

Study on Surface Quality of Nano ZrO<sub>2</sub> Ceramics in Grinding by the Aid of Ultrasonic Vibration

Nano ceramics possesses excellent mechanical property and physical characteristics in contrast to conventional engineering ceramics, so it has tremendous application prospect. Adopting ultrasonic composite processing we describe the influences of grinding speed, grinding depth, wheel granularity and no-spark grinding times on the surface roughness of nano ZrO2 ceramics. By means of SEM and AFM the surface character and critical ductile grinding depth of nano ZrO2 ceramics in the condition of conventional and ultrasonic grinding are also discussed. At last, the residual stress of surface and crystalline phase transformation under the condition of conventional grinding and ultrasonic vibration grinding were analyzed by X-ray diffraction. The research indicated that ultrasonic vibration grinding could obtain nano finished surface with high efficiency. The residual stress of nano ZrO2 ceramics surface is determined much by different grinding styles.

Interface structure of ultrasonic vibration aided interaction between Zn–Al alloy and Al 2O 3p/6061Al composite

Interactions between a Zn–Al alloy and an Al 2O 3p/6061Al composite with and without aid of ultrasonic vibration were examined. Undermining and penetrating phenomena were observed, but the oxide layer was still continuous at most places between the undermining zone and the Zn–Al alloy during interaction without ultrasonic vibration. The generation of shrinkage voids in the penetration zone made the composite unconsolidated. Under ultrasonic vibration, the oxide film disappeared, and the Zn–Al alloy turned into composite materials after ultrasonic aided interaction and the reinforcements (composite blocks) distributed uniformly and had metallurgical bonds with the matrix. The microstructure of solidified Zn–Al alloy could be designed by controlling the degree of mass transfer during interaction.