Ball milling is an important means of preparing ultrafine and nano-sized powders. Although there are many grinding materials available, zirconia is by far the most popular choice.From the point of view of grinding materials, zirconia has three outstanding characteristics compared with other ceramic grinding media: one is high density;Second, the hardness is great;The third is good toughness.Although the purchase cost is high, but the comprehensive use cost is very advantageous, more importantly, its wear is relatively low, especially suitable for high purity materials that can not be polluted, such as grinding electronic paste, etc..
Zirconia beads too small to be seen
Generally speaking, the particle size of the grinding product is about 1/1000 of the grinding medium, so when the product particle size is required at the nanometer level, the grinding medium with smaller diameter needs to be used.Therefore, the quality and size of the grinding medium directly determine the ability and efficiency of ball grinding, and the size of the grinding medium often has a great relationship with the preparation process.At present, the commonly used rolling method has low cost and mature technology, so it is widely used.However, the rolling method has great difficulties in preparing ultrafine beads, which can only be said to be unable to prepare the grinding microbeads with a diameter of 0.05mm, which is the limit of the industry at present.
However, with the improvement of people’s need for real nanomaterials, relevant technology has been fully developed. For example, the Institute of Nuclear and New Energy Technology of Tsinghua University has optimized a set of preparation technology of ultra-fine zirconia beads on the basis of research and summary.The process uses sol-gel technology to mix materials at nanoscale, effectively reducing sintering temperature, and achieving a higher level of product roundness and density.The most important thing is that it has a great advantage in the preparation of small size microbeads, which can easily prepare microbeads with a diameter of less than 50 microns, and the minimum diameter can reach 1 micron.
July 23, 2020