The raw material for sintered silicon carbide ceramics is high purity green silicon carbide with 98-99% content. In the past, silicon carbide ceramic manufacturers chose black silicon carbide particles and black silicon carbide powder to produce wear-resistant and corrosion-resistant silicon carbide pump bodies, silicon carbide nozzles, silicon carbide wear plates, silicon carbide seals and other products.
In recent years, with the spurt of the new energy vehicle industry, there are new prospects for the development of silicon carbide ceramics in the field of lithium batteries. This also puts forward higher requirements for silicon carbide ceramic raw materials. Green silicon carbide has higher purity (99%) and hardness (9.5 on the Mohs scale) than black silicon carbide, as well as better chemical stability and thermomechanical properties. Therefore, for silicon carbide ceramics in new energy-related industries, green silicon carbide with a purity of 99% or higher needs to be selected.
Since the 1960s, silicon carbide has been used to produce high-performance silicon carbide composite ceramics. With high wear resistance and mechanical strength, low density specific gravity, stable chemical and thermomechanical properties, high thermal conductivity, and low coefficient of thermal expansion, silicon carbide ceramics have a wide range of applications in fine chemicals, semiconductors, metallurgy, and defense and military industries.
In the field of lithium batteries, which has been in full swing in recent years, silicon carbide ceramics also play an important role in the preparation of its raw materials, such as.
Fine grinding of lithium iron phosphate
The current lithium battery cathode material is commonly used lithium iron phosphate. Lithium iron phosphate “ultra-fine grinding” needs to maintain the stability of the grinding equipment during high current discharge. This is one of the main means to improve its performance.
Currently the most commonly used equipment in the process is the sand mill, the use of silicon carbide material characteristics can make the sand mill more suitable for lithium iron phosphate production – such as silicon carbide cylinder, high hardness, wear resistance, good thermal conductivity, can quickly take away the heat in the grinding chamber, greatly improving the efficiency of grinding also reduces energy consumption.
High-temperature sintering of ternary materials
The positive materials are generally produced by the reaction of oxide raw materials or precursors at high temperatures, and the crucible is prone to cracking and flaking during rapid heating and cooling, so it needs a vessel with high temperature resistance and good thermal shock resistance to hold oxide raw materials or precursor materials.
The high temperature and corrosion resistance of silicon carbide ceramics, as well as the high load-bearing capacity, are suitable for the high temperature sintering process of ternary materials, which can guarantee the stability and reliability of high temperature calcination.
Silicon carbide ceramics are also very promising in the field of photovoltaics. For example, in the synthesis process of monocrystalline silicon and polycrystalline silicon, the impact resistance, wear resistance and high temperature resistance of silicon carbide ceramics, and the high purity of the surface chemical vapor deposition guarantee the synthesis process of silicon materials; in the heat treatment and oxidation process of silicon wafers, because silicon carbide ceramics have high temperature bearing capacity and high purity, it can make the process processing temperature increase, so as to improve the performance of silicon wafers, so the crystal boat, bracket, cantilever paddle and other core components The core components such as boats, brackets and cantilever paddles are becoming increasingly important kiln components.
At present, silicon carbide manufacturers mostly use green silicon carbide F90 (150 microns), F150 (80 microns), F180 (70 microns) grit and green silicon carbide F240 (50 microns), F2000 (1.5 microns) micro powder.