Five key points for quality control of silicon powder products
Silica powder is a silica powder material made from natural quartz ore, fused quartz, etc., processed by multiple processes such as grinding, precision classification, and impurity removal. Grinding is one of the core processes in the production of silicon powder products. It directly affects its purity, particle size distribution and production cost.
In order to produce silicon powder products with stable quality and high performance, it is necessary to strengthen management and control from the following points:
1. Ball mill control
It is possible to effectively control the impurity content and increase the service life of the equipment by reasonably selecting the grinding media material, controlling the media ratio and filling rate; according to the length to diameter ratio of the ball mill, the structure and distribution of the liner, and the particle size of the grinding, the speed of the ball mill can be reasonably adjusted to promote the grinding The material in the cavity maintains a good state of motion, thereby improving the grinding effect.
2. Particle shaping
By optimizing the process conditions such as equipment operating speed, internal pressure and temperature, material residence time, etc., the regularity of the surface of the silicon powder can be improved, and the fluidity of the product can be improved. dispersion.
3. Mixed compound
Unimodal silica powder cannot achieve the tightest packing, difficult to meet high filling requirements, and cannot maximize the excellent performance of silica powder. One of the ways to increase the filling rate is to mix the silicon micropowder products with different particle size distributions, and form a multimodal distribution through the mixing ratio, which achieves high filling and reduces the oil absorption value of the silicon micropowder.
4. Surface modification
As an inorganic filler, silicon micropowder has problems of poor compatibility and difficulty in dispersion when mixed with organic resins, resulting in poor heat resistance and moisture resistance of materials such as integrated circuit packaging and substrates, which affects the reliability and stability of the product. In order to improve the problem of interface bonding between silicon micropowder and organic polymer materials and improve its application performance, it is generally necessary to modify the surface of silicon micropowder.
5. Production condition control
The key to the production of electronic grade silicon powder is to remove the conductive impurities in the quartz. Therefore, in addition to the selection of purer raw materials, every link of production should minimize the pollution of the product by containers, the environment, and chemicals, and operate strictly.
To avoid contamination of materials during grinding, the grinding media used should be non-metallic materials, such as alumina ceramic balls or silica; the barrel of the mill must also be lined with high-strength wear-resistant materials, such as alumina ceramics, silica or Polyurethane rubber.