Pressureless sintered silicon carbide and reaction sintered silicon carbide are two different methods for preparing silicon carbide ceramics. They have significant differences in the firing process, product technical parameters and product performance.
firing process
Pressureless sintering: silicon carbide products that shrink naturally at 2100 degrees.
Reactive sintering: At lower temperatures, free silicon is infiltrated into silicon carbide.
Product technical parameters
Pressureless sintered silicon carbide: The surface is smoother, the density is higher, and the strength is higher than that of reaction sintering.
Reaction sintered silicon carbide: volume density, hardness, compressive strength, etc. are different from the technical parameters of pressureless silicon carbide products.
Product performance
Pressureless sintered silicon carbide: its mechanical properties at high temperatures and corrosion resistance under strong acid and alkali are much better than reaction sintered silicon carbide.
Reactive sintered silicon carbide: under different pH, temperature, etc., the use time is different. In particular, when the temperature is above 1400°C, the strength of the material decreases rapidly as free Si melts.
Product density
Pressureless sintered products: density between 3.08-3.15.
Reaction sintered products: density is between 2.97-3.05.
Cost and Application
Pressureless sintering: Although the products produced by pressureless sintering have superior performance, it is difficult to completely replace reactive sintering due to the high cost.
Reaction sintering: Due to its low production cost, it is suitable for preparing large-sized and complex-shaped silicon carbide ceramic products.
In summary, pressureless sintered silicon carbide and reaction sintered silicon carbide each have their own advantages and disadvantages, and which method to choose depends on actual application requirements and cost considerations.