China's Refractories

Abstract: Nickel nitrate was introduced into carbon blocks by using ECA aggregates as catalyst-carrier. The Ni-containing anthracite aggregates were firstly prepared by mixing anthracite aggregates in nickel nitrate ethanol solution and then incorporated into carbon blocks after pre-treating. The phase composition, microstructure and properties of all carbon blocks fired at 1 000 ℃ or 1 400 ℃ in a coke bed were studied with the aid of an X-ray diffractomer, a field emission scanning electron microscope, a mercury porosimetry and a laser thermal conductivity meter. The results showed that the addition of Ni-containing anthracite aggregates promoted the formation of one-dimensional nanocarbon and β-SiC whiskers at 1 000 ℃ and the growth of β-Sialon at 1 400 ℃, respectively. Moreover, the cold compressive strength and microporosity characteristics of the carbon blocks with the addition of Ni-containing anthracite aggregates were enhanced and the thermal conductivity was remarkably improved attributing to the high heat conductive network formed by the ceramic phases.

Key words: one-dimensional nanocarbon, β-Sialon, thermal conductivity, carbon blocks