Mesoporous aggregates of nanocrystalline zeolites with MFI and BEA frameworks have been synthesized using a one-pot and single structure directing agent. The effect of different reaction conditions, such as temperature, time, pH and water content, on the particle size, surface area and mesopore volume has been studied. Nanocrystalline and mesoporous ZSM-5, β and Y zeolites were modified with di...

Nanocrystalline cellulose particles are new class of cellulose materials that can find the wide application in various technical areas, biotechnology and medicine. The nanoparticles are usually made by treatment or initial cellulose samples with concentrated sulfuric acid (SA) at various temperatures and following mechanical or ultrasound disintegration. Unfortunately, conditions of existing me...

Nanocrystalline n type ZnO thin films were deposited on SiO2-coated (0.4 μm) p-Si substrates (10-20Ω-cm, 400 μm) by a low cost chemical deposition technique to fabricate ZnO-based resistive sensors for methane detection. The nanocrystalline ZnO needle like structures were grown on RCA cleaned p-Si substrates by successive immersion (100-200 times) into a Sodium

in the present study, nanocrystalline ni50al50-xmox (x = 0, 0.5, 1, 2.5, 5) intermetallic compound was produced through mechanical alloying of nickel, aluminum, and molybdenum powders. alni compounds with good and attractive properties such as high melting point, high strength to weight ratio and high corrosion resistance especially at high temperatures have attracted the attention of many rese...

We have conducted highP-Tsynchrotron X-ray and time-of-flight neutron diffraction experiments as well as indentation measurements to study equation of state, constitutive properties, and hardness of nanocrystalline and bulk nickel. Our lattice volume-pressure data present a clear evidence of elastic softening in nanocrystalline Ni as compared with the bulk nickel. We show that the enhanced over...

Solid solution strengthening in nanocrystalline alloys is studied using sputtered Ni–W as a model system. In the composition range of 0–20 at.% W, the sputtered alloys have a nanocrystalline structure with a grain size that is independent of composition. Nanoindentation of these alloys shows that solute addition increases strength to very high levels, almost in proportion to the solute content....

Experimental methods are demonstrated for studying pressure-dependent material properties and solid phases unattainable at ambient pressure with high-pressure synchrotron nuclear resonance techniques. Pressure presents an intriguing experimental parameter for investigating the problem of excess low-energy (<12 meV) vibrational modes in nanocrystalline materials. A satisfactory explanation for t...

In our previous work (R.J. Asaro, P. Krysl and B. Kad, Philos. Mag. Lett. 83 (2003) p.733; P. Gu, B. Kad and M. Dao, Scr. Mater. 62 (2010) p.361), the intra-granular partial dislocation extension model was shown to be consistent with the experimental data of flow stress in nanocrystalline FCC materials. However, since the averaged extension was taken for a nonuniform loop, the model predicted s...

Mechanical strengthening by grain refinement is a method whereby a material’s strength and hardness can be increased by decreasing the average crystallite grain size. The empirical Hall–Petch relationship mathematically describes grain boundary strengthening and provides guidance for a straightforward way to produce stronger materials. While the phenomenon has been widely explored in nanocrysta...

Bulk nanocrystalline Ti bars (Grade 4, Φ4 × 3000 mm(3)) were massively fabricated by equal channel angular pressing (ECAP) via follow-up conform scheme with the microcrystalline CP Ti as raw material. Homogeneous nanostructured crystals with the average grain size of 250 nm were identified for the ECAPed Ti, with extremely high tensile/fatigue strength (around 1240/620 MPa) and adorable elongat...