The manufacturing method of ceramics (sintered bodies)

1. Manufacturing methods of ceramics
The key to producing the required ceramics lies in optimizing the raw materials. No matter how expensive the manufacturing and evaluation equipment is, if the raw materials are not properly prepared, there will be significant differences (changes) in the performance of the final ceramics, thereby increasing the possibility of producing defective products. However, merely purchasing high-quality raw materials is not enough. It is important to consider cost-effectiveness and find the best processing equipment and conditions that match the raw materials used.

Generally, powder is the starting material for obtaining ceramics, especially dense sintered bodies. Liquids, gases or their composites can also be used as starting materials. The characteristics of the initial powder have a significant impact on the performance of ceramics. The most suitable mixing, grinding methods and processing conditions need to be selected based on the raw materials. Especially when dealing with non-oxide or metal micro-powders (fine powders), it is necessary to pay attention to adsorbed oxygen and surface oxidation. The finer the powder is, the more significant its effect tends to be. In addition, it may also be necessary to pay attention to the optimal addition concentration and dosage of dispersants and organic binders based on the molding conditions.

2. Manufacturing method of sintered bodies

To prepare sintered bodies, a series of processes such as mixing and pulverizing, forming and degreasing, sintering (pre-sintering) and firing (sintering) are generally required.Firstly, let's introduce the process of mixing and pulverizing: 

When using raw material powders that are difficult to sinter and one desires to obtain a dense sintered body under normal pressure conditions, it is common to add a small amount of appropriate sintering aid powder at the same time. These powders are mixed with the main component powders as the starting materials. 

The mixed methods can be roughly classified into: 
Dry mixing: Done in the air (sometimes also in an inert atmosphere) 
Wet mixing: carried out in water or organic solvents 
Sometimes, during the mixing process, grinding treatment is also carried out simultaneously.

The most suitable method for mixing and grinding needs to take into account the following factors comprehensively: 
The average particle size and particle size distribution of the raw materials 
The allowable amount of impurities that can be mixed in 
The degree of agglomeration of the powder 

When necessary, screening machines or classification devices will also be used to ensure that only the powder within the optimal particle size range is used as raw material.

Hot Isostatic Pressing, HIP

Self-propagating combustion sintering

Spark Plasma Sintering, SPS