The inferred crystallographic class of circumstellar silicon carbide based on astronomical infrared spectra is controversial. We have directly determined the polytype distribution of circumstellar SiC from transmission electron microscopy of presolar silicon carbide from the Murchison carbonaceous meteorite. Only two polytypes (of a possible several hundred) were observed: cubic 3C and hexagona...

The sintering behavior of calcium pyrophosphate (CPP, Ca2P2O7)-doped beta-tricalcium phosphate [TCP, Ca3(PO4)2], prepared by solid state reaction, was investigated in-situ, using dilatometry. Pure beta-TCP undergoes phase transition to alpha-TCP at about 1200 degrees C; hence pure beta-TCP ceramics should be sintered bclow 1200 degrees C. Pure beta-TCP sintered body can achieve a relative densi...

Nanocomposites films of (polymer blend-ceramics) were prepared from (PVA-PAA) blend and (PVA-PAA) blend doped with niobium carbide nanoparticles for humidity sensors have low cost, easy fabrication, high sensitivity, lightweight and high corrosion resistance. The structural, electrical and optical properties of (PVA-PAA-NbC) nanocomposites have been studied. The D.C electrical properties of (PV...

The effects of charging on a ZrO2 sintered body due to electron irradiation were investigated by means of electron holography. The charging effects were quantitatively evaluated as a function of the incident electron density. The ZrO2 sintered body was positively charged within a transmission electron microscope. By means of simulations taking into account reference wave modulation due to a lon...

Fully stabilized zirconia/graphene composites are very promising advanced structural materials having mixed ion–electron conductivity for energy storage and conversion applications. The existing methods of the composite manufacturing have a number disadvantages that limit their practical use. Thus, search new sintering is an actively developing area. In this work, we report first time applicati...

The effect of grapheme-nanosheets (GNs) on the mechanical properties and microstructure S390 HSS alloy was investigating. sample reinforced with 0.25, 0.5, 0.75 wt.% GNS. Powder metallurgy technique used to prepare all samples. elemental powders were milled in a planetary ball mill by 10:1 powder ratio speed 350 rpm for 48 hours, mixed warm compacted uni-axial press at 550?C under 500 MPa then ...

The effect of high-frequency (HF) electric fields on the crystallization and sintering rates of a lithium aluminum germanium phosphate (LAGP) ion conducting ceramic was investigated. LAGP with the nominal composition Li1.5Al0.5Ge1.5(PO4)3 was crystallized and sintered, both conventionally and under effect of electrical field. Electrical field application, of 300 V/cm at 1 MHz, produced up to a ...

The microstructure of the hypereutectic Fe-Cr-C alloy is observed by optical microscopy (OM). The initial growth morphology, the crystallographic structure, the semi-molten morphology and the stacking faults of the primary M7C3 carbide are observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The in-suit growth process of the primary M7C3 carbide was observe...