Papers by Author: Kyle Jiang

Abstract: In order to solve pressure measurement problems in the fields of aerospace, petroleum and chemical industry, mobile and military industry, a oil-filled isolated piezoresistive high pressure sensor has been developed with the range of 0~100 MPa, and was able to work reliably under high temperature of above 200 °C. Based on MEMS (Micro Electro-Mechanical System) and SIMOX (Separation by Implantation of Oxygen) technology, the piezoresistive sensor chip has been developed. By high temperature packaging process, the oil-filled isolated high pressure sensor was fabricated with the sensor chip and corrugated diaphragm. The experimental results showed that the oil-filled isolated high pressure sensor had good performances under high temperature of 200 °C, such as linearity error of 0.07%FS, repeatability error of 0.04%FS, hysteresis error of 0.03%FS.

Abstract: Motif parameters were introduced to characterize line edge roughness (LER) of a nanoscale grating structure. Firstly with electron beam lithography employed the expected nano-scale grating structure with linewidth of 16 nm was fabricated on positive resist. Then the line edge profiles of the structure were extracted and their LERs were characterized. The results showed that the evaluation method is rather simple, effective and recommendable.

Abstract: In this study, microcomponents of nickel (Ni) based nanocomposite were obtained by electrochemical co-deposition of Ni and alumina (Al2O3) nanoparticles into the microfabricated photoresist moulds from a nickel sulfamate bath with the presence of multi-wall carbon nanotubes (MWCNTs). The examination of dispersion behaviour of Al2O3 nanoparticles in nickel sulfamate bath with MWCNTs showed that the surfaces of the fillers are positively charged in a wide range of pH value, which favours the co-deposition of Al2O3 nanoparticles and MWCNTs with Ni. Results of SEM and EDX characterizations showed that the Al2O3 nanoparticles were uniformly distributed in the Ni matrix and their contents were improved with the presence of MWCNTs in the solution. It was also found that the mechanical properties of Ni were enhanced by the nanoparticulates in the Ni matrix.

Abstract: Alumina microcomponents have distinguishing advantages over Si counterparts. However, the shrinkage of alumina, as high as 20%, makes it difficult to produce precision components that require a high tolerance. A new fabrication process is presented to greatly reduce the shrinkage. The process consists of forming an Al powdered component through sintering and transforming the Al powdered component into an alumina part. In this way, the shrinkage occurring in sintering the Al powder component will be compensated by the expansion occurred when Al transforms into alumina. The process involves producing micro-moulds, preparing metallic paste, filling the micro-moulds with the metallic paste, demoulding, sintering the green Al patterns and finally oxidising the sintered Al-based components to achieve alumina components. The process was proven successful. Characterization of the sintered alumina microcomponents has been undertaken, including SEM image analysis, density and scale measurements.

Abstract: A new approach is explored to achieve sintered aluminium alloy from metallic powder mixtures without compression or adding Mg. In this approach, mixtures of micron-sized aluminium powder (average size of 2.5 μm) and nano-sized alloying elemental powder of Cu and Sn (less than of 70nm), at appropriate proportions to compositions of Al-6wt%Cu, Al-6wt%Cu-3wt%Sn with and without adhesive binder were prepared by magnetic stirring. Then, the powder mixture was poured into a crucible and heat treated at a temperature of 600°C for 11 hours in inert atmosphere of N2 or Ar. In this paper, we investigate the debinding behavior of loosely packed Al-based powder mixture and the microstructural development and mechanical property sintered parts using a combination of thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray diffractrometry (XRD) and hardness test.