Coating on Porous Si₃N₄ Based Substrate with Sol-Gel Slurry

Abstract

The coating was prepared on porous Si₃N₄ based substrate by dip-coating from sol-gel slurry. The slurry was made by adding pretreated silicon into alumina sol. The coated substrate was heated at 1420°C in nitrogen atmosphere. The phase of dried powder from slurry was studied by X-ray diffraction. The surface morphology of coated substrate was determined by scanning electronic microscope. The results indicated that the slurry well infiltrated into porous substrate and filled up surface pores effectively. The coating bonded with substrate firmly without obvious interface. The results showed that the main phases of coating were β-Sialon and O′-Sialon.

Keywords:

• Coating
• silicon
• alumina sol
• chemical synthesis and surface properties