Spontaneous Infiltration of Iron Silicides into Silicon Carbide Powder Preforms

Abstract

The infiltration of liquid Fe 3 Si (mp of ϳ1300°C), Fe 5 Si 3 (mp of ϳ1210°C), and FeSi (mp of ϳ1410°C) into SiC powder preforms was performed at various infiltration temperatures for 60 min under either argon flow or dynamic vacuum. The amount of infiltration under various infiltration conditions was studied as a function of infiltration temperature. For the preforms as-pressed from raw SiC powder, the amount of infiltration of the three silicides under argon flow was independent of their melting points, but suddenly increased within a common temperature range from 1450°to 1550°C. Thermodynamic analyses indicated that the common temperature range corresponded to the temperature at which the SiO 2 on the surface of the SiC particles was decreased under argon flow. Infrared spectroscopy showed SiO 2 on the surfaces of as-received SiC powder particles, but not on the surfaces of the SiC powder particles fired under argon at 1600°C. The amount of infiltration of the as-pressed SiC under vacuum and of fired SiC under argon and vacuum exhibited an obvious dependence on the silicide melting points. This was attributed to the SiO 2 reduction taking place at temperatures lower than the melting points of the silicides. The amount of infiltration was then controlled by the melt viscosity.

Reaction sintered Fe–Sialon ceramic composite: Processing, characterization and high temperature erosion wear behavior

“…It suggests that they were erosion worn by the impact particles evidenced by their shape change from angular to spherical. Fe 3 Si alloy is brittle at room temperature, but it will become more ductile at high temperatures below its melting point of 1300 • C [27]. In other words, the Fe 3 Si alloy phase could deform to some extent when eroded by the SiC grits at high temperature, which may consume the impacting energy and reduce the erosion damage to the Fe-Sialon composite.…”

SiCp/Cu composites prepared by pressureless infiltration of copper into porous SiC preforms

“…The infiltration extent was characterised by f, which is defined as the percentage of the total porous volume in the preform filled by copper alloy. The expression is as follows 7 f ~rc {3 : 2r r Cu (1{r)…”

Investigation of the tribochemical reaction mechanism in dry-type CMP of 6H-SiC substrate

“…At the SiC/SiO 2 interface, Pan et al [32] believed that SiO 2 produced on the SiC surface can prevent the penetration of ferrosilicon into the SiC interior, and the high penetration of ferrosilicon into the SiC occurs only at high temperatures (≥1525°C). The above research results are consistent with the detection results of EDS in Figure 4.…”