Effect of additive composition on porosity and flexural strength of porous self-bonded SiC ceramics

Abstract

The effect of additive incorporation in porous self-bonded SiC (SBSC) ceramics fabricated from a mixture of coarse SiC powder (³65 µm), Si and C is investigated here. Generally, it was found that the additive reduced the porosity and increased the flexural strength of the SBSC ceramic material. This was consistent with the presence of necking in the ceramic microstructure. The flexural strength of the material without additive (control sample) was ³1617 MPa and this was found to be enhanced up to ³33 MPa using 2 wt % B and ³38 MPa, using a mixture of 1 wt % Al + 1 wt % B. Thus, the porous SiC ceramic with AlB additive (typical flexural strength ³38 MPa at 42% porosity) is very promising, contrasting its mechanical properties with the cost-effectiveness of the raw materials.

Processing of alumina‐coated glass‐bonded silicon carbide membranes for oily wastewater treatment

“…The flexural strength of Si‐bonded porous SiC ceramics was 29‐70 MPa at 43%‐70% porosity . The flexural strength of self‐bonded porous SiC ceramics was 18‐38 MPa at 36%‐44% porosity . The flexural strength of sodium borate–bonded SiC ceramics was 37 MPa at 52% porosity .…”

“…56,57 The flexural strength of self-bonded porous SiC ceramics was 18-38 MPa at 36%-44% porosity. 58,59 The flexural strength of sodium borate-bonded SiC ceramics was 37 MPa at 52% porosity. 29 The flexural strength of partially sintered SiC ceramics was 26-57 MPa at 50%-56% porosity.…”

Processing and properties of macroporous silicon carbide ceramics: A review

“…The microstructure of porous self-bonded SiC (SBSC) ceramics consists of SiC crystallites bonded with synthesized SiC [173]. A typical microstructure of the porous self-bonded SiC ceramics is shown in Fig.…”

Flexural Strength of Macroporous Silicon Carbide Ceramics

“…대표적인 분말 소결공정으로는 소결온도를 낮추거나 휘스커 또는 입자크기가 큰 입자(grit)를 첨가하여 소결성을 저하시켜 부분 소결하는 방법, 11) 고분자 미세구 (microbeads)와 같이 고온에서 분해되는 기공 형성제를 첨 가하는 방법, 3) 폴리우레탄 폼(foam)에 탄화규소 슬러리를 코팅하여 폴리우레탄 폼을 분해시켜 다공질 탄화규소 세 라믹스를 제조하는 방법 12) 등이 있으며, 세라믹 전구체를 이용한 공정으로는 폴리카보실란 (polycarbosilane)과 같은 Si 기반 고분자 전구체를 열분해 시켜 탄화규소를 제조하는 방법, 13) 폴리실록센 (polysiloxane)에 활성 필러(filler)로서 탄소를 첨가하여 탄소열환원법으로 다공질 SiC 세라믹스를 제조하는 방법 14,15) 및 폴리실록센과 같은 Si-based 고분자 전구체에 CO 2 를 포화시켜 열역학적인 불안정성을 가함으 로써 다공질 SiC 세라믹스를 제조하는 방법이 있다. 16) 결 합재를 이용한 다공질 탄화규소의 대표적인 공정은 소결 첨가제를 사용하지 않고 2100 o C 이상의 고온에서 SiC 입 자의 necking을 일으키는 재결정화 방법, 17) 뮬라이트 결합 탄화규소(mullite-bonded SiC), 7,18) 실리케이트 결합 탄화규소 † Corresponding author : Young-Wook Kim E-mail : ywkim@uos.ac.kr Tel : +82-2-2210-2760 Fax : +82-2-2215-5863 제48권 제5호(2011) (silicate-bonded SiC), 19) 질화규소 결합 탄화규소 (silicon nitride-bonded SiC), 20) 다공질 반응소결 탄화규소, 21) 실리 콘과 카본을 반응시켜 합성된 탄화규소를 결합재로 사용한 자기결합 탄화규소 세라믹스 (self-bonded SiC ceramics) 제 조법 [22][23][24][25][26]…”