The Preparation and Properties of Clay Bonded Silicon Carbide by Using Silicon Carbide Dusting Powder

In this paper, clay bonded silicon carbide was prepared through pressureless sintering process with silicon carbide dusting powder as raw materials and clay as sintering additive. The effects of the ball-milling method, sintering temperature and clay contents on the density, microstructure and mechanical properties of clay bonded silicon carbide refractory were studied. The planetary ball-milling was a good method to improve the density of the green body, and the density was increased simultaneously with an increase of the clay content. The liquid phase derived from low-melting eutectic mixtures of clay could prevent the superlative oxidation of silicon carbide. The mass increment of sintered samples decreased firstly and then increased at the sintering temperature range from 1250 to 1500 °C. The open porosity of samples decreased with the clay addition at a content range from 10 to 30 wt.%. The bending strength of the samples decreased firstly and then increased with the clay addition increasing. The optimum condition for preparing clay bonded silicon carbide with silicon carbide dusting powder was sintering at 1350 °C with 20 wt.% clay, and the obtained sample with a porosity of 24% achieved the bending strength of 78±7 MPa.

Influence of Grain Composition and Sintering Temperature on Performance of Silicon Carbide Refractory Material

Silicon carbide with diffierent granularity and three grain composition was used as raw material. Silicon carbide refractory material was prepared in oxidizing atmosphere at 1400 °C, 1450 °C and 1500 °C for 3 h. Performence of samples were researched by measurements of apparent porosity, bulk density, bending strength at room temperature, thermal shock resistance and thermal expansion rate, and analyzed by SEM. The results showed that samples sintered at 1400 °C have low thermal expansion rate and apparent porosity, high bending strength and bulk density, good thermal shock resistance, compact texture as well. It can be deduced that (1.0-0.5mm) / (0.5-0.1mm) / (45μm) / (5μm) = 50 / 17/ 20/ 13 is the best grain composition to improve integrated performance of silicon carbide refractory material.

Research on Refractory Material Corrosion in Steelmaking Engineering

Researched on the refractory material corrosion by experiments. Each refractory was measured to take four different parts, and the average corrosion thicknesses of silicon carbide, quartz and corundum were 0.52mm, 1.03mm and 1.40mm. The corrosion of corundum refractory was most serious, and quartz refractory had a certain degree of corrosion, but it was not very serious. The corrosion of silicon carbide refractory was the least. In the experiment in intermediate frequency furnace, only upper and lower parts of slag line were connected to the refractory and the degree of corrosion was little for silicon carbide crucible. Slag part of the wall thickness was about 16.6mm after the reaction. Amorphous master alloy parts of the wall thicknessis about 16.9mm. For quartz crucible, refractory corrosion was much bigger, which was 10 mm thick before reaction. The erosion thick was about 2~3mm. It was a little thicker than corrosion experiment in static crucible.

The Mechanism Research on the Refractory Material Corrosion in Material Engineering and its Applications

The mechanism of refractory material corrosion was analyzed. The laboratory amorphous alloy smelting of the mother prefabricated crucible, reaction process is basically to crucible refractory material of blast furnace slag corrosion, melt corrosion is small. Generally smelting amorphous mother alloy was a difficult thing, and it shown that the basicity was better around 1.0. Compared with quartz refractory, it is good to choose the silicon carbide refractory materials, while smelting amorphous alloy.