Experimental investigation of laser surface processing of flexure silicon nitride ceramic

• Published in: Transactions of Nonferrous Metals Society of China Vol. 16; no. B02; pp. 558 - 565
• Main Authors: SUN, Li, MALSHE, A.P., JIANG, Wen-ping, MCCLUSKEY, P.H.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.06.2006
• Subjects: flexural strength; fracture origin; laser surface processing; Si 3N 4; silicon nitride ceramic; surface integrity; 实验研究; 挠曲强度; 氮化硅陶瓷; 激光表面处理; 物理性质; flexural strength; Si 3N 4; silicon nitride ceramic; surface integrity; fracture origin; laser surface processing
• ISSN: 1003-6326
• DOI: 10.1016/S1003-6326(06)60256-2

A continuous wave carbon dioxide （CO2） laser （λ=10.6 μm） was employed to treat the surface of Si3N4 MOR （modulus of rupture） bars. The effects of the CO2 laser process on physical and mechanical properties of ground Si3N4 samples were investigated. Scanning electron microscopy （SEM） analysis shows that the area occupied by cavities and fracture is decreased by about 49.4% after laser treatments. Cross-sectional metallography results indicate that the secondary YSiAlON phase in the Si3N4 ceramic is softened/melted and flowed into the defects. Four-point bending tests show that the flexural strength of the treated samples is improved to 10.9%. Fractographic analysis show that the fracture origins move from the surface to subsurface. It is concluded that laser surface processing have significant effects on fracture behavior of flexure Si3N4 ceramic.