Nik Rozlin Nik Masdek

Effect of sintering temperature on zinc substituted calcium phosphate ceramics

Calcium phosphate ceramics were substituted with several concentrations of zinc ions (0, 5, 10 and 15 mol%) using precipitation method. The effect of sintering temperature at 900 and 1000°C on zinc substituted calcium phosphate ceramics were observed. By increasing the sintering temperature, XRD peaks for zinc substituted calcium phosphate ceramics changed significantly. At sintering temperature of 900°C, hydroxyapatite phase was the major phase in the calcium phosphates containing 0 and 5 mol% zinc. However, at the sintering temperature of 1000°C, hydroxyapatite phase was partly transformed to another phase which was tricalcium phosphate. FESEM observations at sintering temperature of 1000°C exhibit that the particle size of the samples increased with addition of more zinc ions.

Characterization of electrodeposited nanocrystalline cobalt-iron coating with different iron content

The nanocrystalline cobalt-iron (CoFe) alloy coatings were produced using the electrodeposition technique. Effect of different iron concentrations on the surface morphology, surface roughness, grain size, crystalline texture and wear resistance of the deposited CoFe were investigated. Nanocrystalline CoFe alloy coatings were electrodeposited in a sulfate bath with varying iron sulfate concentration. The temperature and pH were maintained at 40 °C and 3, respectively. The results show that grain size decreased with an increase of iron content in the deposited CoFe alloy coatings. The preferred orientation plane for the alloy coating exhibited an FCC and BCC phase depending on the iron content present in the coating. The microhardness of the nanocrystalline CoFe alloy coating were also seen to increase with higher iron content in the deposited coating. Furthermore, the surface roughness was seen to increase with higher iron concentration of the deposited alloy coating. Interestingly, higher wear resistance ...