首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   62篇
  免费   1篇
  国内免费   2篇
化学工业   18篇
金属工艺   17篇
机械仪表   10篇
能源动力   1篇
无线电   5篇
一般工业技术   14篇
  2023年   1篇
  2022年   1篇
  2021年   5篇
  2020年   4篇
  2019年   1篇
  2018年   1篇
  2017年   1篇
  2016年   1篇
  2015年   3篇
  2014年   2篇
  2013年   1篇
  2012年   1篇
  2011年   5篇
  2010年   5篇
  2009年   10篇
  2008年   6篇
  2007年   4篇
  2006年   4篇
  2005年   1篇
  2004年   3篇
  2003年   1篇
  2002年   1篇
  2001年   2篇
  2000年   1篇
排序方式: 共有65条查询结果,搜索用时 15 毫秒
1.
Nano-hardness (Hnano) and nano-elastic modulus (Enano) of corroded coating surface layer were investigated using nano-indentation after epoxy coated specimens were immersed in 5% NaCl solution. The penetration depths (d) of corrosive media into epoxy coating were calculated fitting the curves of (H/E)nano vs. indentation depth (h). EIS spectra of epoxy coated specimens immersed in 5% NaCl solution for different time were measured. Finally the relationship of capacitance (Cf,T) of corroded epoxy coating with the penetration depth of corrosive media was studied. The experimental results showed that the transportation process of corrosive media into epoxy coating was studied through the profiles of (H/E)nano with indentation depth. The penetration depth of corrosive media into the epoxy coating increases rapidly with immersed time firstly, and then increases slowly. The capacitance of corroded epoxy coating has a linear function relationship with the penetration depth of corrosive media into epoxy coating. Nano-indentation can be used to study the transportation process of corrosive media into organic coating.  相似文献   
2.
《Ceramics International》2020,46(17):26530-26538
8 wt% yttria-stabilized zirconia (8YSZ) powders are fabricated as high-temperature based materials via a solid-state reaction method and ground into spheres in this paper. Following that, 4 wt% Nickle (Ni), 4 wt% Hexagonal Boron Nitride (hBN) and 4 wt% PHB (Polyphenyl ester) are added to 8YSZ for getting 8YSZ ceramic-based abradable seal powders (8YSZ CASp). Then, the 8YSZ CASp are sprayed on the stainless steel substrate with a NiCoCrAlY transition layer by an atmospheric plasma spraying (APS) technology. The phase structure, surface morphology and the cross-section topography of the fabricated are analyzed, the indentation hardness and nano-indentation test are conducted. The experiments of 8YSZ ceramic-based abradable seal coatings (8YSZ CASc) show that the deposition efficiency and porosity are respectively 78.5% and 21.8%, the bond strength is 4.6 MPa, the cycle number of thermal shock resistance is 37 times, those parameters prove that the fabricated 8YSZ CASc are promising abradable seal coatings.  相似文献   
3.
Fluorinated polyurethane dispersions (FPUDs) were synthesized using HDI isocyanurate, polyester polyol and DMPA with varying concentrations of trifluoro ethanol (TFE) in the range of 0–9 wt%. Further FPUDs were characterized by FT-IR and 1H NMR for structural elucidation. Effects of trifluoro ethanol on the dispersion were evaluated by particle size analyzer. It was observed that with increase in TFE, particle size increases. Topography and contact angle were studied by atomic force microscopy (AFM) and goniometer, respectively. To gain more insight into the formation of roughness, power spectral density (PSD) analysis was carried out. It was found that with increase in TFE content, surface roughness increases due to migration of fluorinating agent on the coating substrate and consequently water repellency increases. Nano indentation of coating revealed that fluorinated coating possesses less stiffness and elastic modulus, due to the presence of fluorine on the coating. Further, coatings were analyzed for thermal properties by thermogravimetry analysis (TGA) and differential scanning calorimetry (DSC) which shows the enhancement in thermal stability and glass transition temperature with increase in TFE content. Anti-graffiti test was carried out which showed improved resistance with increasing fluorine content.  相似文献   
4.
纳米压入法研究核电站-回路主管道材料的热老化行为   总被引:1,自引:0,他引:1  
采用纳米压入方法对核电站一回路主管道的双相不锈钢材料热老化行为进行定量研究.通过对单独的铁素体相和奥氏体相的纳米压入实验,得到随着老化时间的增加,两者在相同压入深度时的压入载荷增加;根据动态测试技术得到的纳米硬度增加,表现为强度提高;而纳米压入塑性变形能降低,表现为韧性降低;并且不同老化时间下铁素体相的强度和韧性都要高...  相似文献   
5.
Surface acoustic wave characterization of a thin, rough polymer film   总被引:1,自引:0,他引:1  
R. Côte  J.-P. Celis 《Thin solid films》2009,517(8):2697-2701
Laser generated surface acoustic waves (SAW) in a heterodyne diffraction scheme is a powerful technique for elastic characterization of thin films and it is frequently used on samples of high optical quality. We show that the method can also be effectively used in difficult conditions, on rough samples. Measurements are presented on a 3 µm thick film of polymer, spin-coated on steel, and on the same sample after addition of an aluminum coating. The experimental data are interpreted using a model assuming a stack of perfect layers. The analyses show good consistency within the SAW results for both configurations, and consistency with nano-indentation results, cross-validating both approaches.  相似文献   
6.
Spark Assisted Chemical Engraving (SACE) is an unconventional technique for surface micro-machining of non-conductive materials specially glass. SACE offers many advantages for fabrication of microfluidic and Lab on Chip devices. However the exact mechanism of material removal in this technique is not fully understood. Besides, the changes in the properties of the machined sample have not been studied so far. In this letter, the material removed from glass surface is evaluated and the results of nano-indentation test for measurement of the hardness of machined micro-channels surface is reported. Based on the amount of removed mass during machining and results of nano-indentation test on machined samples it is concluded that hardness and density of the machined zones decrease during the process.  相似文献   
7.
Laser micro-cladding by powder injection has been used to produce Co-based alloy clad strips with geometrical characteristics in the micrometer range (width: 45 µm, height: 15 µm). A new experimental set-up based on the use of a single mode fibre laser and a powder microfeeder was used to produce such coatings. A systematic study on the influence of several processing parameters (laser power, processing speed, mean precursor particle size) on the geometric features of the clad strips was carried out. Moreover Young's modulus and hardness measurements of the micro-clad strips allow affirming that these micro-cladding coatings maintain the mechanical properties typical from this hardfacing alloy.Reparation of defective microparts, surface functionalisation of small areas, or rapid fabrication of prototypes are areas of application of this rapid one step microcoating technique.  相似文献   
8.
Surface characterization of 6H-SiC (0001) substrates in indentation and abrasive machining was carried out to investigate microfracture, residual damage, and surface roughness associated with material removal and surface generation. Brittle versus plastic deformation was studied using Vickers indention and nano-indentation. To characterize the abrasive machining response, the 6H-SiC (0001) substrates were ground using diamond wheels with grit sizes of 25, 15 and 7 μm, and then polished with diamond suspensions of 3 and 0.05 μm. It is found that in indentation, there was a scale effect for brittle versus plastic deformation in 6H-SiC substrates. Also, in grinding, the scales of fracture and surface roughness of the substrates decreased with a decrease in diamond grit size. However, in polishing, a reduction in grit size of diamond suspensions gave no significant improvement in surface roughness. Furthermore, the results showed that fracture-free 6H-SiC (0001) surfaces were generated in polishing with the existence of the residual crystal defects, which were associated with the origin of defects in single crystal growth.  相似文献   
9.
In this paper, the influence of single walled carbon nano tubes (SWCNTs) addition on the tribological properties of the polyimide (PI) films on silicon substrate was studied. PI films, with and without SWCNTs, were spin coated onto the Si surface. Coefficient of friction and wear durability were characterized using a ball-on-disk tribometer by employing a 4 mm diameter Si3N4 ball sliding against the film, at a contact pressure of ∼370 MPa, and a sliding velocity of 0.042 ms−1. Water contact angle, AFM topography, and nano-indentation tests were conducted to study the physical and mechanical properties of the films. SWCNTs marginally increased the water contact angle of PI film. The addition of SWCNTs to PI has increased the hardness and elastic modulus of pristine PI films by 60–70%. The coefficient of friction of PI films increased slightly (∼20%) after the addition of SWCNTs, whereas, there was at least two-fold increase in the wear life of the film based on the film failure condition of coefficient of friction higher than 0.3. However, the film did not show any sign of wear even after 100,000 cycles of rotation indicating its robustness. This increase in the wear durability due to the addition of the SWCNTs is believed to be because of the improvement in the load-bearing capacity of the composite film and sliding induced microstructural changes of the composite film.  相似文献   
10.
The rolling contact fatigue of sprayed alumina ceramics with a nominal composition of Al2O3–2.3 mass% TiO2 was studied with a two-roller test machine under a pure rolling contact condition with oil lubricant. The influence of undercoating of sprayed Ni-based alloy on the rolling contact fatigue was investigated. The failure mode of all sprayed rollers was spalling caused by subsurface cracking. The undercoating did not contribute to the improvement of the rolling contact fatigue life. The elastic modulus of the alumina sprayed layer evaluated with the nano-indentation method was around 85 GPa. The depths of the observed subsurface cracks corresponded approximately to the depths where the orthogonal shear stress or the maximum shear stress calculated with two-dimensional FEM became maximum.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号