Abstract:In this paper, we have studied on the absorbing properties of three different types of SiC absorbers such as ultra-fine SiC, SiC whisker and nanometer SiC. Electromagnetic parameters of the three types of SiC were tested in the frequency range of 2~18GHz. Both the real and imaginary parts of complex permittivity of nanometer SiC are higher than that of others. The attenuation constant of nanometer SiC is higher than that of ultra-fine SiC and SiC whisker, increasing from 93.7 to 766.5 with increasing frequency… Show more
“…Besides, several studies also reported that the microwave absorbing properties of SiC increased with the decreasing of particles size. 42,43 For these reasons, SiCNWs was chosen as the microwave susceptor in this study.Figure 5.Shear strength of the welded sample subjected to different microwave heating duration.…”
Section: Resultsmentioning
confidence: 99%
“…Earlier studies had shown that SiCNMs have better dielectric properties and good microwave absorption efficiency than bulk SiC. [32][33][34][35][36] Due to their improved microwave absorption at high temperature and higher dielectric loss than SiC nanoparticles, 1D-SiCNMs such as SiC nanowires and nanowhiskers have gained significant interest among SiCNMs. 37,38 For an instance, Kuang et al studied the microwave absorbing properties of SiC nanowires of various lengths.…”
Up to present, no study has reported on the use of silicon carbide nanomaterials (SiCNMs) as susceptor for microwave welding of thermoplastics. Therefore, in this study, silicon carbide nanowhiskers (SiCNWs) was attempted as the microwave susceptor for the microwave welding of polypropylene (PP). It was observed that SiCNWs are capable of absorbing microwave and converting them into heat, leading to a sharp increase in temperature until it reaches the melting point of PP substrates. The microwave welded joint is formed after the molten PP at the interface between PP substrates is cooled under pressure. The effect of microwave heating duration and solid loading of SiCNWs suspension was studied and reported. The formation mechanism of SiCNWs reinforced PP welded joint was proposed in this study. With these remarkable advantages of microwave welding and enhanced mechanical properties of the welded joint, it is believed that this study can provide a new insight into welding of thermoplastic and material processing through short-term microwave heating.
“…Besides, several studies also reported that the microwave absorbing properties of SiC increased with the decreasing of particles size. 42,43 For these reasons, SiCNWs was chosen as the microwave susceptor in this study.Figure 5.Shear strength of the welded sample subjected to different microwave heating duration.…”
Section: Resultsmentioning
confidence: 99%
“…Earlier studies had shown that SiCNMs have better dielectric properties and good microwave absorption efficiency than bulk SiC. [32][33][34][35][36] Due to their improved microwave absorption at high temperature and higher dielectric loss than SiC nanoparticles, 1D-SiCNMs such as SiC nanowires and nanowhiskers have gained significant interest among SiCNMs. 37,38 For an instance, Kuang et al studied the microwave absorbing properties of SiC nanowires of various lengths.…”
Up to present, no study has reported on the use of silicon carbide nanomaterials (SiCNMs) as susceptor for microwave welding of thermoplastics. Therefore, in this study, silicon carbide nanowhiskers (SiCNWs) was attempted as the microwave susceptor for the microwave welding of polypropylene (PP). It was observed that SiCNWs are capable of absorbing microwave and converting them into heat, leading to a sharp increase in temperature until it reaches the melting point of PP substrates. The microwave welded joint is formed after the molten PP at the interface between PP substrates is cooled under pressure. The effect of microwave heating duration and solid loading of SiCNWs suspension was studied and reported. The formation mechanism of SiCNWs reinforced PP welded joint was proposed in this study. With these remarkable advantages of microwave welding and enhanced mechanical properties of the welded joint, it is believed that this study can provide a new insight into welding of thermoplastic and material processing through short-term microwave heating.
“…Recently, nanomaterials had become tremendously popular for their enhanced performance owing to their high aspect ratio. Liu et al, for example examined the microwave absorbing properties of two different sized SiC, namely ultra-fine SiC (diameter <1000 nm) and nanometre SiC (diameter < 100 nm) [19]. They show that both dielectric constant and loss factor of nanometre SiC are greater than ultra-fine SiC.…”
Microwave welding is becoming more popular than conventional joining methods due to its advantages such as rapid and localised heating as well as applicable to components with complicated geometry. Previously reported susceptor, such as carbonaceous materials and conductive polymers, are toxic and the welding process involving these susceptors is time-consuming. Because of its exceptional microwave absorption and biocompatibility, silicon carbide nanowhiskers (SiCNWs) was employed as the microwave susceptor for microwave welding. Microwave welding in this study comprises of only three simple steps: SiCNWs suspension preparation, SiCNWs application and microwave heating. The weld strength of welded joint was then characterised using tensile test and energy dispersive x-ray spectroscopy equipped scanning electron microscopy (EDS-SEM) to study its mechanical properties and cross-section microstructure. The influence of microwave irradiation time was studied in this study, and it is found that the weld strength rose with the extension of microwave irradiation time, until a maximum weld strength of 1.61 MPa was achieved by 17 s welded joint. The development of SiCNWs reinforced PP nanocomposite welded joint layer is responsible for the enhanced weld strength. Prolonged heating duration may also result in flaws such as void formation at the welded joint, which subsequently lowered the weld strength to 0.60 MPa when the heating duration was extended to 20 s. In sum, a strengthen welded joint can be formed with rapid microwave heating under the proper control of heating duration.
“…SiC nanomaterials (SiCNMs) are lightweight with notable mechanical properties, high chemical and thermal stability, making them ideal microwave susceptor [20,21]. Besides, earlier research shows that the large specific surface area and interfacial polarisation of SiCNMs improved their microwave absorption performance as compared to microsized SiC [22,23]. Up to present, the use of SiCNMs as susceptor for microwave welding of thermoplastic has not yet been reported in any studies.…”
Currently, welding is the most efficient way for joining of plastic. Due to its rapid heating, efficiency in term of time and energy, and ability to be applied on components of any shape, microwave welding stands out from other welding methods. Additionally, SiCNWs was proposed as the microwave susceptor for the microwave welding of thermoplastic in this work due to its high dielectric loss and biocompatibility. To produce microwave welded joint, SiCNWs was first mixed with acetone to obtain a SiCNWs suspension. After that, SiCNWs was drop casted onto the targeted area of PP, allowed to dry and then microwave irradiated. In this work, the microwave heating time studied ranged from 15 s to 20 s. SEM and single lap shear test were used to characterise the microwave welded joint. From the findings, the tensile strength increased as the microwave heating duration increased from 15 s to 18 s, due to formation of SiCNWs/PP nanocomposite welded joint layer with increasing thickness. Yet, when the microwave heating time was prolonged to 20 s, the tensile strength decreased to 0.85 MPa. Besides, a void was observed at the welded joint and it is believed that the presence of void causes the welded joint to weaken when force is applied. Under properly regulated of microwave heating time, a strengthened nanocomposite welded joint can be produced which demonstrate great promise in plastic welding.
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