Preparation method of alumina ceramic valve core ceramic chip and product thereof

A preparation method of an alumina ceramic valve core ceramic chip, comprising following steps:

• (1) putting alumina with a purity of more than 99.5 percent, a sintering aid and SiC crystal whiskers into a ball milling tank for ball milling, wherein a ball milling medium of absolute ethyl alcohol is used during the ball milling;
• the sintering aid is nano alumina and zirconium oxide, wherein a particle size of the nano alumina is 20 to 30 nm, and the nano alumina is added in an amount 0.5 to 1 wt %;
• the zirconium oxide is added in the amount of 0.5 to 1 wt %;
• and the SiC crystal whiskers is added in the amount of 2 to 5 wt %;
• and
• (2) after ball milling a mixed material is obtained, drying the obtained mixed material;
• then adding 5% by mass of a polyvinyl alcohol (PVA) water solution to the mixed material, and after ageing for 20 to 30 h, granulating the mixed material to form a granulated powder;
• filling the granulated powder into a hard rubber mold sleeve;
• sealing and then putting into a cold isostatic press for molding at a pressure of 140 MPa to 160 MPa for 5 to 10 min to form a blank body, and drying the obtained blank body;
• then machining the blank body and performing a rubber discharging treatment in a muffle furnace at 600 to 800 DEG C under a microwave auxiliary condition for 1 to 2 h;
• then sintering at 1500 to 1600 DEG C for 1 to 2 h;
• cooling to room temperature along the muffle furnace;
• and finely machining to obtain the alumina ceramic valve core ceramic chip.