Yb2O3 is an efficient sintering additive for enhancing not only thermal conductivity but also the high-temperature mechanical properties of Si3N4 ceramics. Here we report the fabrication of dense Si3N4 ceramics with high thermal conductivity by the gas pressure sintering of α-Si3N4 powder compacts, using only Yb2O3 as an additive, at 1900 °C under a nitrogen pressure of 1 MPa. The effects of Yb...

Molecular dynamics simulations of approximately 15 Å thick intergranular films (IGFs) containing SiO2 and CaO in contact with two surface terminations of the prism (101̄0) and basal planes (0001) of Si3N4 were performed using a multibody interatomic potential. Samples with the same composition (1.5 mol% CaO) and number of atoms but different crystal planes (i.e., the prism and basal planes of Si...

A 28 g sample of the Qingzhen enstatite (EH3) chondrite was subjected to chemical and physical separation procedures to yield several grain-size residues. Ion mapping of isotopes of Si, O, and C in the ion microprobe of two size fractions (QZR4: 0.4–0.8 lm; QZR5: 0.8–2 lm) identified 55 30Si-depleted candidates out of 37,917 Si-rich grains and six 18O-depleted grains out of 54,410 oxides. Subse...

AA8011-5 wt% Si3N4, AA8011-10 AA8011-15 and AA8011-20 Si3N4 were developed via two-steps stir casting route of liquid metallurgy. The influence the inclusion non-conductive inorganic nano ceramic on thermal properties, electrical behavior, corrosion resistance performance conductive AA8011 matrix was investigated. responses thermogravimetric analysis (TGA) differential (DTA) revealed a decrease...

The current work is concerned with the synthesis of aluminium (AA6061-T6) matrix composites (AMCs) reinforced 15 and 20 weight percentages silicon nitride (Si3N4) particulates using indigenously fabricated electric stir casting furnace bottom discharge arrangement. major concern in AMCs ceramic particles wettability route, it was overcome by adding 2% magnesium melt, proper incorporation time, ...

In order to prepare Ni clusters embedded in amorphous Si3N4, Ni and Si3N4 layers have been alternatively deposited using sputtering techniques. The nominal Ni layer thickness ranged from 2 to 60 Å and the number of layers was varied accordingly so as to keep the total amount of Ni constant. Extended x-ray-absorption fine-structure EXAFS spectroscopy has been used to study the Ni clustering as w...

Efficient nanopowder processing requires knowledge of the powder's mechanical properties. Due to the large surface area to volume ratio, nanoparticles experience relatively strong attractive interactions, leading to the formation of micron-size porous structures called agglomerates. Significant effort has been directed towards the development of models and experimental procedures to estimate th...

Composite scaffolds consisting of polymers reinforced with ceramic nanoparticles are widely applied for hard tissue engineering. However, due to the incompatible polarity of ceramic nanoparticles with polymers, they tend to agglomerate in the polymer matrix which results in undesirable effects on the integral properties of composites. In this research, forsterite (Mg2SiO4) nanoparticles was sur...