Determination of Transformation Induced Heat Transfer Coefficients in Mechanical Properties of Powder Metallurgy Steels
2 Abstract: Powder metallurgy has been used for the manufacture of fully dense, which have not reacted composites consisting of a matrix of copper containing 50 -60 vol% particles with negative thermal ZrW2O8 expansion. On cycling between 25 and 300°C, the compounds showed coefficients thermal expansion which varies rapidly with temperature and significantly larger than expected by theory. Improvements in adhesion strength and thermal properties of composite materials have been achieved in atomized copper alloy with small additions of chromium to increase the interfacial bonding in composite Cu / diamond from a nano-sized thin Cr3C2layer.
Particle rearrangement during liquid phase sintering of Cu–20Zn and Cu–10Sn–10Pb prepared from prealloyed powder
Abstract It would be useful to be able to produce brass and bronze components made from prealloyed powders by supersolidus liquid phase sintering. The microstructures obtained in such alloys are sensitive to constituent alloying elements and small change in sintering temperature. Although the formation of liquid during sintering is potentially attractive for densification, the effects of gravity on the liquid phase can result in graded densification. Evaporation of alloying elements and their solubility in the base metal also affect the extent to which heterogeneous cross-sections are obtained. The aim of the present study was to examine the effect of alloying and sintering temperature on the mode of particle rearrangement, and consequently on graded densification, by microstructural and fractographic analysis. Comparing the fracture morphology from top to bottom of the fracture surface is also helpful in developing a model to describe the phenomena during sintering of similar alloys.
Silver–Gelatin Method for the Determination of Trace Amounts of Carbon Monoxide in Air
The use of silver–gelatin complex was found suitable for the determination of trace amounts of carbon monoxide in air. Silver–gelatin complex is reduced by carbon monoxide to give intensely colored sol. Measurement of the color intensity of the stable silver sol enables the determination of carbon monoxide successful under various environmental conditions. The detection limit is 2–100 ppm. The relative standard deviation for the determination of 10 ppm carbon monoxide is 2.6%.