Oxidation of Silicon Carbide‐Reinforced Oxide‐Matrix Composites at 1375° to 1575°C

Abstract

Oxidation studies were conducted on AI2O3-SiC and mullite-Sic composites at 1375" to 1575°C in O2 and in Ar-l% 02. The composites were prepared by hot-pressing mixtures of A1203 or mullite and SIC powders. The reaction products contained alumina, mullite, an aluminosilicate liquid, and gas bubbles. The parabolic rate constants were about 3 orders of magnitude higher than those expected for the oxidation of Sic. Higher rates are caused by higher oxygen permeabilities through the reaction products than through pure silica. Our results suggest that oxygen permeabilities are comparable in the three condensed phases observed in the reaction products. [Key words: composites, silicon carbide, oxidation, mullite, alumina.] used were 1-to 4-pm Sic particles,' 0.3-pm alumina,' and <6-pm mullite.g Powder mixtures of desired composition were homogenized, in batches of -0.1 kg, by ball-milling for 18 h using alumina balls and 2-propanol as a dispersing agent. The ball-milled powders were dried at room temperature, and subsequently pressed into pellets 31.6 mm in diameter. The pellets were hot-pressed at 1650°C for 10 min using a pressure of 25 MPa. The hot-pressed samples attained a density of at least 99% of theoretical value. Silicon carbide particles were well dispersed in the matrix in the hot-pressed samples, as shown in the microstructures in Fig. 1.Hot-pressed samples were cut into coupons 14 mm X 10 mm x 1 mm in size. A 1-mm-diameter hole was drilled

High Temperature Oxidation of Y<SUB>2</SUB>O<SUB>3</SUB> Partially-Stabilized ZrO<SUB>2</SUB> Composites Dispersed with Ni Particles

“…There are some phenomenological reports on the oxidation behavior of oxide ceramic composites dispersed metals, 3) carbides and nitrides. [4][5][6][7][8] In this study, oxidation behavior on Y 2 O 3 -partially stabilized ZrO 2 dispersed Ni particles is investigated to establish the kinetic model for designing ceramic composites with metallic particle dispersion. Partially stabilized ZrO 2 with Y 2 O 3 -doping (refer to PSZ) is one of the most popular engineering ceramics due to high mechanical strength and toughness.…”

High-temperature oxidation of ceramic matrix composites dispersed with metallic particles

“…Luthra et al [7] classified oxidation mode of oxide matrix composites dispersed with non-oxide dispersoid. A schematic illustration of the oxidation mode is shown in Fig.…”

“…High-temperature oxidation of thermal barrier coatings (TBCs) with a functionally graded structure has been reported briefly [5]. There are also a few phenomenological studies on the oxidation behavior of oxide ceramics with metals [4,6] or non-oxide ceramic dispersoid such as SiC or TiC [7][8][9][10][11].…”

High-Temperature Oxidation of Nickel-Dispersed Mullite Composites in Air

“…The oxidation kinetics of ceramic-based composites depends on diffusions of ions and cations along the matrix grain boundaries. Mullite (3Al 2 O 3 .2SiO 2 ) is known as a great ceramic material for high-temperature applications because of its oxidation resistance and creep properties [11][12][13] . In other words, mullite-based composites with Ni dispersion (Ni/mullite) could be a potential material for high-temperature applications.…”