Effect of dispersant on the rheological properties of gelcast fused silica ceramics

International Conference on Advances in Materials and Manufacturing Applications 2016

Kandi, Kishore Kumar^1 ; Pal, Sumit Kumar^2 ; Rao, C.S.P.^1

Department of Mechanical Engineering, National Institute of Technology, Warangal

506004, India^1

Department of Ceramic Engineering, National Institute of Technology, Rourkela

769008, India^2

关键词: Fabrication technique;    High flexural strength;    Low dielectric constants;    Near net shape;    Rheological property;    Silica ceramic;    Silica particles;    Silica suspensions;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/149/1/012063/pdf
DOI  :  10.1088/1757-899X/149/1/012063

来源: IOP

【 摘 要 】

Fused silica ceramics with high flexural strength, low porosity, low dielectric constant and loss tangent were fabricated by gelcasting, a near-net shape fabrication technique. Fused silica suspensions with solid loading as high as 73 vol.% with low viscosity has been prepared using various dispersants in acidic and alkaline regions/medium. Commercially available Darvan 821A, Darvan C-N, Dolapix A88 and Dolapix CE64 were used as dispersants. Investigations were carried out to determine the suitable dispersant and effects of dispersant percentage, pH value, zeta potential, and solid loading on the rheological properties of the suspension. Darvan 821A showed better results in the suspension of fused silica particles in aqueous gelcast system. At 1250°C the flexural strength of fused silica bodies is as high as 52.3 MPa, and the dielectric constant and loss tangent (1 MHz) were as low as 3.25 and 1 X L52M0-3for solid loading of 70 vol.% respectively. Such properties are highly desirable for ceramic radomes used in lower range missiles.