Preparation of alumina balls: The slurry is dispensed and dropped into the solution using a droplet spraying device (microsphere forming instrument)10%Boric acid in glycerol. Slurry droplets pass throughPVAThe cross-linking reaction between boric acid solidifies and sinks to the bottom of glycerol. Wash the solidified green body with ethanol and air dry it. Finally, the dried green body is filled into an alumina crucible coated with platinum and sintered in an air atmosphere. The sintering temperature range is1100～ 1500.

The effect of different amounts of boric acid added on the solidification time of slurry droplets during the preparation of alumina balls. As the amount of boric acid added increases, the solidification time of the slurry droplets gradually shortens, that is, boric acid andPVAThe rate of molecular cross-linking reaction is increased. When the amount of boric acid added is less than10%When the curing time is too long, the slurry droplets have not yet solidified when they reach the bottom of the device, resulting in a low rate of microsphere formation; When the amount of boric acid added is greater than10%At that time, the curing time was too short, and the slurry droplets had already solidified before shrinking and forming in the solidification bath, resulting in poor sphericity of the microsphere green body; When the amount of boric acid added is10%When the solidification time of the slurry droplets is4．5minWhen the slurry droplets first enter the coagulation bath, they do not solidify rapidly, but contract into an ideal spherical shape under the tension between the two liquid phases. When the droplets reach the bottom of the device, they solidify and form.

Accurate and controllable size of slurry droplets (ball diameter) through microsphere forming technology (microsphere forming instrument)0.5-1Millimeters can be used to prepare uniform slurry droplets, which can be solidified and baked to obtain ceramic microspheres with uniform particle size. The droplet jet rapid prototyping device applies a controllable extrusion pressure to the top of the slurry cylinder, driving the slurry to shoot out droplets from the dropper at the bottom of the slurry cylinder. The diameter of the nozzle needle and the extrusion pressure of the slurry directly affect the particle size of the liquid droplets, and have controllability over the particle size of ceramic microspheres. The influence of different nozzle needle diameters and slurry extrusion pressures on the average particle size of microspheres. With the increase of needle diameter or slurry extrusion pressure, the average particle size of microspheres significantly increases. Ceramic microspheres of different particle sizes can be prepared using needles of different diameters and slurry extrusion pressures, thereby achieving controllability of ceramic microsphere particle size.

We can provide testing for alumina balls using a microsphere forming instrument, prepare the slurry and forming solution for alumina balls, and provide detailed ball requirements for testing.