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71.
Effects of thermal and mechanical treatments on a titanium-based conversion coating for aluminium alloys 总被引:1,自引:0,他引:1
The influence of mechanical deformation and heating on the protective performance of a chromium-free conversion treatment for aluminium alloys has been assessed by polarisation and AC impedance measurements. Protection is unlikely to be seriously compromised by typical production operations. 相似文献
72.
《稀有金属材料与工程》2006,23(4):12-16
透过性能对用于过滤分离、流体混合、布气分流等方面的多孔材料是一项十分关键的质量指标。主要介绍了多孔材料透过性能的表征方式,包括流体流动的基本概念、层流条件下流体的透过性能表征、多孔材料透过性能的综合表征、气体透过多孔材料时渗透系数的具体表征等方面。 相似文献
73.
A systematic investigation of the magnetic and transport properties of Ti doped La0.67Ca0.33MnO3 was reported. The Ti substitution for Mn ions results in a reduction in ferromagnetism and conductivity. The metal-insulator transition temperature is close to Curie temperature which decreases from 274 to 82 K as x increases from 0 to 0.17. The most important effect of Ti doping is to introduce spin clusters in the samples due to the distortion of local lattice and the inhomogeneous magnetic structure induced primarily by the random distribution of Mn ions. A maximum magnetoresistance ratio as large as 90% in 1 T at 122 K was obtained for the sample with x =0. 055, which is four times larger than that obtained for LCMO sample at 272 K. There is a remarkable field-history dependent MR in the cooling process for the doped samples while such phenomenon disappears in the warming run. The resistivity follows well the variable range hopping behavior in paramagnetic state. Both the size effect and spin dependent hopping of carriers between the spin clusters should be considered in this system. 相似文献
74.
本文简要回顾了陶瓷墙地砖深加工的工艺理论和机械设备。对陶瓷墙地砖深加工的自动抛光生产线和组成生产线的工艺单机作了一般介绍。指出设计陶瓷墙地砖深加工工艺单机时要注意的主要问题,并提供了解决这些问题的方法。 相似文献
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78.
杨加峰 《武汉理工大学学报(材料科学英文版)》2005,20(Z1)
1Introduction HA(hydroxyapatite)wasakindofbioactiveceram ics,whichhadexcellentbiocompatibilityandtissueaffin ityinthatitscomponentsweresimilartothoseofhuman bone[1].Soitwasthebestknownhumanbonesubstitute,andunprecedentedeffecthadbeenharvestedinrecenttwo d… 相似文献
79.
HUANG Jianfeng CAO Liyun ZHANG Chuanbo WU Jianpeng HE Haiyan 《武汉理工大学学报(材料科学英文版)》2005,20(B12):138-140
Nano-particle hydroxyapatite ( HA ) was prepared with a novel ultrasonic precipitation process and the as-prepared nanopowder was used to produce hydroxyapatite ( HA ) coatings on titanium substrate via plasma spraying. The phase and the microstructare of the coating were characterized by X- ray diffraction (XRD) and scanning electron microscopy (SEM). Results showed that spherical particles could be prepared by ultrasonic precipitation process; and a corresponding dense HA coating with molten surface and low-porosity cross-section structure was acquired. During the plasma spraying process, new phases of Ca3 ( PO4 )2 and Ca2 P2O7 were generated. After heat-treating at 800℃ for 1 h, the contents of Ca3 ( PO4 )2 and Ca2 P2O7 decreased while HA content increased. Tensile adhesion tests showed that the plasma sprayed coating prepared with the spherical nanoparticles exhibited high tensile bond strength. 相似文献
80.
A method to produce monodisperse magnetic composite spheres with diameters from less than 100 nm to more than 1 μm in water solution is reported. The spheres consist of a dielectric silica core and a cobalt/cobalt oxide shell which can be protected from further oxidation with an outer shell of silica or, alternatively, they can be covered with the polymer polyvinylpyrrolidone as a stabilizer. The formation of a uniform magnetic shell proceeds with the adsorption of metallic cobalt seeds, produced by the reduction of cobalt chloride with sodium borohydride, on a self‐assembled layer of polyelectrolytes on the silica core. In the second step, an outer silica shell can be formed by the hydrolysis and condensation of (3‐aminopropyl)trimethoxysilane and tetraethoxysilane. The double‐shell composite spheres show excellent sphericity, monodispersity, and a magnetic hysteresis loop at room temperature. 相似文献