Fabrication and liquid–solid, two-phase erosion wear behaviour of β-Sialon ceramic from pyrophyllite by carbothermal reduction and nitridation

Abstract

In this paper, β-Sialon ceramic was formed with pyrophyllite as raw material and coke as reductant by carbothermal reduction and nitridation in flowing nitrogen atmosphere. Then, the erosion wear property of β-Sialon ceramic was measured. When the pre-synthesized temperature was 1400°C, the effects of carbon additions (with theoretical carbon addition and carbon in excess of 10–50wt.%) on the phase compositions of the products were studied by X-ray diffraction. β-Sialon ceramic was sintered at 1600°C, and its erosion wear behavior was examined with the use of a self-designed, liquid–solid, two-phase flow erosion equipment. Results show that the optimum carbon addition to fabricate the β-Sialon ceramic powders was in excess of 10wt% at 1400°C. Under these conditions, the pre-synthesized powders were composed of β-Sialon as the main crystalline phase and β-SiC as the secondary phase. The relationship between volume erosion amount per area of the specimens and erosion time can be explained by two exponential equations—ΔV=−5.2t2+10.4t and ΔV=−0.006t2+0.273t+4.884 in two stages.