Early Characterization of NdFeB and NdFeB /Co-Al Composites of Sintering Using SPS

The purpose of this study is to obtain a permanent magnet end-product from NdFeB and NdFeB / Co-Al composite material from SPS sintering which has high density with small grain size and strong corrosion resistance. NdFeB powder and NdFeB/Co-Al composites (0.2 and 0.5weight%) of several micron-sized particles resulting from the milling process have been successfully sintered with a temperature parameter of 800°C for 10 minutes and a pressure of 50MPa in dies with a diameter of 20 mm in a vacuum chamber. Optical micrographs show that the grains are uniformly and smoothly distributed throughout the surface. This is showing the types of grain distributions which has good mechanical properties. The X-ray analysis result shows the phase analysis confirms the presence of such main PM phases as Nd, Fe and B. From SEM observation, the particles have irregular shapes and a large particle size distribution. The density value of the sample is in the range of 7.1 - 7.3. From the density measurement it is also known that the sintering sample with SPS has a high-density level which is close to 100%, so it can be said that it has formed fully dense.

Mechanism of Carbon Contamination in Transparent MgAl2O4 and Y3Al5O12 Ceramics Sintered by Spark Plasma Sintering

An investigation of MgAl2O4 spinel and Y3Al2O5 (YAG) materials sintered by spark plasma sintering (SPS) was performed. The optical properties of the materials are modified depending on the powder source and the SPS sintering conditions. Spectrophotometer and Raman analysis are presented in this work, along with optical and scanning electron microscope (SEM) observations and cathodoluminescence analysis. The results show a correlation between carbon contamination and the optical properties of the materials. Herein, the source of the contamination is explained, along with its genesis and diffusion. The carbon contamination originates from the powder itself (carbonates), as well as the SPS environment (papiex® graphite foil, graphite die, graphite felt) to form carbon clusters. During the high-temperature SPS process, carbon from those carbon clusters diffuses, resulting in an increase in the contamination volume, thereby increasing the light absorption.