Quantitative microstructural analysis was performed on Si3N4 materials doped with 5 wt% Y203 and 5 wt% Sc203 as sintering aids. Two different processing routes were utilized to achieve complete densification: (i) gas-pressure sintering of Si3N4-starting powders (SSN) and (ii) post-sintering of reaction-bonded Si3N4 (SRBSN). Apart from quantitative evaluation of grain diameter and aspect ratio o...

We stdy the spectral reflectivity of conical-, cylindricaland parabolic-shaped silicon nitride (Si3N4) sub-wavelength structures (SWS). A multilayer rigorous coupled-wave approach is adopted to estimate the reflection properties of Si3N4 SWS. Optimal shapes of SWS in terms of effective reflectance are analyzed over a range of wavelength. The results of our study show that a 3.15% effective refl...

A new fabrication method is proposed to produce nanostructures on monocrystalline silicon based on the friction-induced selective etching of its Si3N4 mask. With low-pressure chemical vapor deposition (LPCVD) Si3N4 film as etching mask on Si(100) surface, the fabrication can be realized by nanoscratching on the Si3N4 mask and post-etching in hydrofluoric acid (HF) and potassium hydroxide (KOH) ...

This study investigates the grinding of sintered silicon nitride using a SiC wheel with a fine abrasive grit size and dense vitreous bond. The difference of hardness between the green SiC abrasive and sintered Si3N4 workpiece (25.5 vs. 13.7 GPa) is small. Large grinding forces, particularly the specific tangential grinding forces, are observed in SiC grinding of Si3N4. The measured specific gri...

In the fabrication of microstructures in SiO2 , etch selectivity of SiO2 to masking, etch stop, and underlayer materials need to be maintained at corners and inclined surfaces. The angular dependence of the SiO2-to-Si3N4 etch selectivity mechanism in a high density fluorocarbon plasma has been studied using V-groove structures. The SiO2 etch rate on 54.7° inclined surfaces is lower than on flat...

INTRODUCTION The contacting surfaces subjected to progressive loss of material known as 'wear,' which is unavoidable between contacting surfaces. Similar kind of phenomenon observed in the human body in various joints where sliding/rolling contact takes place in contacting parts, leading to loss of material. This is a serious issue related to replaced joint or artificial joint. CASE DESCRIPTI...

In this paper, we report the preparation and characterization of both the ZnO nanocrystalline thin films and nanopowder by ultrasonic spray pyrolysis technique. ZnO films were grown on polished Si(1 0 0) and amorphous glass substrates at different deposition temperature range varying from 200 to 500 1C. Both orientation and the size of the crystallites were found to depend on the substrate and ...

It has been well established that SiC is a dominant mineral in the condensation sequence of carbon-rich stars (or C-stars). The presence of other mineral species in interstellar dust surrounding C-stars may be indicative of exotic formation conditions for these objects. Observers have long held out hope for detecting the compound silicon nitride (Si3N4) in stellar spectra; however, previous att...

Preparation of nanomaterials with various morphologies and exploiting their novel physical properties are of vital importance in nanoscientific field. Similarly to the III-N compound semiconductors, Si3N4 nanostructures also could be potentially used for making optoelectronic devices. In this paper, we report on an improved Fe-catalyzed chemical vapour deposition method for synthesizing ultra-l...

Ultralong Si3N4 nanowires (NWs) were successfully synthesized with size controlled in N2 gas by using an efficient method. The diameters of the Si3N4 NWs increased when the flow rate of N2 gas increased, with average diameters of 290 nm from flow rates of 100 ml/min, 343 nm from flow rates of 200 ml/min and 425 nm from flow rates of 400 ml/min. Young's modulus was found to rely strongly on the ...