Erosive Wear Mechanism of New SiC/SiC Composites by Solid Particles

Abstract

A solid-particle erosive wear test by impinging silicon carbide (SiC) powders was carried out at room temperature over a range of median particle sizes of 425-600 lm, speed of 100 m/s and impact angle of 90°a nd assessed by wear measurements and scanning electron microscopy. Erosive wear behaviour was examined on newly fabricated nano-powder infiltration and transient eutectoid (NITE) SiC/SiC composites and two commercial composites by the chemical vapour infiltration (CVI) and NITE fabrication route. Microstructural observation was performed to examine the correlation between erosive wear behaviours and fabrication impurities. Conspicuous defects were observed in the prototype materials as the forms of porosity, fibre deformation, residual oxide, pyrolytic carbon (PyC) deformation, PyC cleavage, among others. Erosive wear behaviour was rather serious in the prototype of fabricated composites, which employ pre-SiC fibre and phenolic resin. Two dominant erosive wear mechanisms were observed: delamination of constituents, mainly caused by erosive crack propagation, and fragmentation and detachment of constituents, which usually resulted from erosive impact. A unit size of delamination was the most decisive factor affecting wear volume. The bonding strength of each constituent was mostly affected by various forms of porosities. Therefore, the fundamental cause and subsequent results must be carefully elucidated. The correlation of microstructural defect and wear behaviour was investigated with the aim of reducing dominant wear by improving fabrication conditions. The final product of the cost-effective composite had a 2.5-fold higher resistance than the commercial CVI composite. Consequently, by controlling fabrication impurities, we have been successful in developing and improving a new fabrication technique; consequently, the known defects are rarely observed in final product. A schematic wear model of erosive wear mechanisms is proposed for the newly fabricated SiC/SiC composites under particle erosion.

STUDY OF EROSIVE WEAR BEHAVIOUR ONSIC/SICCOMPOSITES

“…In addition, the impact performances of monolithic SiC ceramics and SiC/SiC composites in the range of impact energy of 0.05 J to 0.0067 J clearly show not only the limitation of monolithic but also strongly supports the greatest needs of composites for the structural applications 7 ( Fig. 1).…”

“…Composite is sometimes the only and inevitable choice to answer the purpose, due mainly to the brittle nature of ceramics [1][2][3][4][5][6][7][8][9][10] well-known as fracture mechanisms subjected to most of wear contacts, especially under sliding 1-2 and erosion [3][4][5][6] . In addition, the impact performances of monolithic SiC ceramics and SiC/SiC composites in the range of impact energy of 0.05 J to 0.0067 J clearly show not only the limitation of monolithic but also strongly supports the greatest needs of composites for the structural applications 7 ( Fig.…”

“…SiC fibrereinforced SiC matrix (SiC/SiC) composite is one of the cutting edges of material science, which perfectly meets the constant demands of superior material in the nuclear energy system and the aerospace propulsion system regarding energy science [1][2][3][4][5][6][7][8][9] . Wear is one of significantly important phenomena to control for the higher durability and reliability of mechanical components [1][2][3][4][5][6][7] . In the field of aerospace propulsion system, erosive wear on SiC/SiC composites is of significant issue to achieve high energy efficiency with sustainability [3][4][5][6][7] .…”

“…Wear is one of significantly important phenomena to control for the higher durability and reliability of mechanical components [1][2][3][4][5][6][7] . In the field of aerospace propulsion system, erosive wear on SiC/SiC composites is of significant issue to achieve high energy efficiency with sustainability [3][4][5][6][7] . In the same purpose, the world's famous jet fighter engine also decided to adopt SiC matrix composites and now successfully moving to the fourth stage of research.…”

“…As shown in Table 1, LPS route also divided into two different fabrication processes regarding to the adaptation of pyrolytic carbon (PyC) interfaces 5,6 . The detail methods of fabrication 6,8 , and test of impact 7 and wear 3-6 are described in elsewhere. Briefly, it is the test of material performance against foreign object debris (FOD) but the diversity of sizes of projectile in the range of 3 mm to 500 μm; it is divided into two categories, the ballistic impact and the solid particle erosion (SPE).…”