Kun LI
,
Nanlin SHI
,
Jun GONG
,
Chao SUN
,
null
,
null
,
null
,
null
材料科学技术（英）
Four kinds of Mg alloys reinforced with carbon fibres were fabricated by a gas pressure infiltration technique. The fibres were pre-coated a SiO2 layer prior to fabrication. Different microstructures and interactions in the fibre-matrix interface of these composites were observed by transmission electron microscopy (TEM). The results showed that the interfacial interaction strongly depended on the content of Al in the Mg-based matrices. The microstructure of the interface could then be controlled by adjusting the Al content of the Mg-based matrix. In addition, fibres extracted from different Mg-based matrix all had some degradation owing to the interfacial reaction and the fibre-matrix interdiffusion.
关键词:
Carbon fibre
,
null
,
null
,
null
Aiying WANG
,
Kwangryeol Lee
,
Chao SUN
,
Lishi WEN
,
null
,
null
,
null
,
null
材料科学技术（英）
During the growth of the hot filament chemical vapor deposition (HFCVD) diamond films, numerical simulations in a 2-D mathematical model were employed to investigate the influence of various deposition parameters on the gas physical parameters, including the temperature, velocity and volume density of gas. It was found that, even in the case of optimized deposition parameters, the space distributions of gas parameters were heterogeneous due primarily to the thermal blockage come from the hot filaments and cryogenic pump effect arisen from the cold reactor wall. The distribution of volume density agreed well with the thermal round-flow phenomenon, one of the key obstacles to obtaining high growth rate in HFCVD process. In virtue of isothermal boundary with high temperature or adiabatic boundary condition of reactor wall, however, the thermal round-flow was profoundly reduced and as a consequence, the uniformity of gas physical parameters was considerably improved, as identified by the experimental films growth.
关键词:
Gas physical parameters
,
physical
,
parameters
,
simulations
,
di
Hao DU
,
Jun GONG
,
Chao SUN
,
Rongfang HUANG
,
Lishi WEN
,
W.Y.Cheung
,
S.P.Wong
材料科学技术（英）
In this work, the prerequisite and mode of electromagnetic response of Al nanofilms to electromagnetic wave field was suggested. Reflectance, transmittance in infrared region and carrier density of the films was measured. With the carrier density of the films, the dependence of their plasma frequencies on the film thickness was obtained. On the other hand, the dependence of absorptance on the frequency of electromagnetic wave field was set up by using the measured reflectance and transmittance, which provided plasma frequency---film thickness relation as well. Similarity of both plasma frequency---film thickness relations proved plasma resonance as a mode of electromagnetic response in Al nanofilms.
关键词:
Aluminum nanofilm
,
null
,
null
Fuhe YUAN
,
Zhiwei HUANG
,
Zhongguang WANG
,
Chao SUN
,
Shijie ZHU
材料科学技术（英）
Detonation spraying has advantages of strong bonding without heating substrates, high coating speed, low requirements for the quality of surface treatment of substrates and others. In the present research, yttria stabilized zirconia powders were used for detonation spraying thermal barrier coatings (TBCs) on a Ni-base superalloy with a bond coat of NiCrAlY. Thermal exposure tests were conducted at a constant temperature in air. After thermal exposure, microstructure observation, element distribution analysis and hardness measurement were carried out. The cracking behavior of the as-prepared and preoxidized TBCs specimens was investigated.
关键词:
Detonation spraying
,
null
,
null
,
null
Aiying WANG
,
Chao SUN
,
Rongfang HUANG
,
Lishi WEN
材料科学技术（英）
A three-dimensional model was developed to investigate the influence of various hot filaments parameters on substrate temperature fields that significantly affect the nucleation and growth of diamond films over large area by hot-filament chemical vapor deposition (HFCVD). Numerical simulated results indicated that substrate temperature varies as a function of hot filaments number, radius, temperature, emissivity, the distance between filaments, and the distance between substrate and filaments arrangement plane. When these filaments parameters were maintained at the optimal values, the homogeneous substrate temperature region of 76mm×76mm with the temperature fluctuation no more than 5% could be obtained by a 80mm×80mm hot filaments arrangement plane. Furthermore, the homogeneous region could be enlarged to 100mm×100mm under the condition of supplementary hot filaments with appropriate parameters. All of these calculations provided the basis for specially optimizing the hot filaments parameters to deposit uniform diamond film over large area by HFCVD.
关键词:
HFCVD
,
null
,
null
,
null
Meng CHEN
,
Xuedong BAI
,
Jun GONG
,
Chao SUN
,
Rongfang HUANG
,
Lishi WEN
材料科学技术（英）
Indium tin oxide (ITO) films were prepared on polyester, Si and glass substrate with relatively high deposition rate of above 0.9 nm/s by DC reactive magnetron sputtering technique at the sputtering pressure of 0.06 Pa system, respectively. The dependence of resistivity on deposition parameters, such as deposition rate, target-to-substrate distance (TSD), oxygen flow rate and sputtering time (thickness), has been investigated, together with the structural and the optical properties. It was revealed that ail 110 films exhibited lattice expansion. The resistivity of ITO thin films shows significant substrate effect: much lower resistivity and broader process window have been reproducibly achieved for the deposition of ITO films onto polyester rather than those prepared on both Si and glass substrates. The films with resistivity of as low as 4.23 x 10(-4) R cm and average transmittance of similar to 78% at wavelength of 400 similar to 700 nm have been achieved for the films on polyester at room temperature.
关键词:
