Zirconia and alumina ceramic processing steps:

There are three main molding processes for ceramic processing. One is slip injection molding, which is mainly completed through physical dehydration and chemical condensation to increase ionic strength. It is mainly suitable for the production of large ceramic parts with complex shapes. The second is hot injection molding. Ceramic powder is mixed with a binder at high temperature, injected into the mold under the action of compressed air to cool and form, and then dewaxed under the protection of inert powder, and then fired into ceramics with dimensions. Precision and high production efficiency. The third is tape casting, which has the characteristics of high flexibility.

Step 2: Degreasing and degluing.

In addition, to dry pressing molding, the plasticizer added must be removed after the product is molded, otherwise, it will affect the quality of the product. It is usually removed by degreasing and degluing.

Step 3: Sintering.

The purpose of sintering when processing zirconia ceramics is to fix its chemical and physical properties and to achieve the desired effect on the surface. There are mainly pressureless sintering, hot press sintering, static pressure sintering, microwave sintering, plasma sintering, etc.

Production of silicon nitride ceramics

  1. Normal pressure sintering

Nowadays, many times when people make silicon nitride ceramics, they use normal pressure sintering, which mainly has certain requirements in terms of decomposition temperature. Generally, the temperature is between 1,700 and 2,000 degrees Celsius. Therefore, the ceramics produced in this way also have very outstanding performance in terms of strength.

  1. Reaction sintering

The so-called reaction sintering, as the name suggests, is a process in which silicon nitride ceramics are made through certain physical and chemical reactions. It mainly presses silicon powder into a green body of the required shape, and then puts it into a nitriding furnace for reaction. This method can save a certain amount of cost to a large extent, but it still costs a lot of time, so it should generally be considered carefully.

  1. Air pressure sintering

In the past two years, people have paid great attention to air pressure sintering, and have invested a lot of manpower and material resources in it. Silicon nitride ceramics that have been sintered by air pressure generally have the characteristics of high toughness, high strength, and good wear resistance. Various complex-shaped products close to the final shape can be directly produced, thus greatly reducing production costs and processing costs. , so it is more suitable for some large-scale production.

 

Forming of aluminum nitride ceramic substrates

The casting method has also become an important part of the electronics industry

The main molding process using aluminum nitride ceramic substrates.

1 ball mill pulping

In the preparation of aluminum nitride slurry, organic mixed solvents such as dispersants, binders, plasticizers, etc. are usually added to obtain slurry characteristics that are easy to cast and mold. In addition, Y203 is generally added to act as a sintering aid under normal pressure sintering conditions. The viscosity of the slurry has an important impact on the performance of the substrate.

  1. Tape casting

Tape casting has high production efficiency and is easy to achieve continuous and automated production, reduce costs, and achieve mass production. The thickness of the substrate produced can be as thin as less than 10μm and as thick as more than 1mm.

Three glue discharge

Since the substrate blank produced by the tape casting method contains a large amount of organic matter, its internal porosity is large and its strength is low. In order to prevent the above defects from occurring, it is pre-sintered in a nitrogen atmosphere furnace at 1100°C. Sintering can improve the strength of the blank, reduce the porosity, and obtain AIN substrate materials with high flatness and good performance.

Four sintering

After debonding, the aluminum nitride substrate will be sintered at high temperatures. The key points of the sintering process of high thermal conductivity aluminum nitride substrate include the sintering method, the addition of sintering additives, control of the sintering atmosphere, etc. There are generally five commonly used sintering processes for AlN substrates, namely hot press sintering, pressureless sintering, microwave sintering, discharge plasma sintering and self-propagating sintering. Among them, hot pressing sintering is currently the main process for preparing high thermal conductivity densified AIN ceramics.

 

Boron nitride ceramic production process

The sintering methods of H-BN ceramics mainly include pressureless sintering, hot press sintering, hot isostatic pressing sintering, and discharge plasma sintering. Among them, pressure-free sintering is a conventional sintering method that is simple to operate and easy to control the temperature. However, due to its high porosity, it can only be used in situations where mechanical strength is not required; hot isostatic pressing sintering can produce high-density products. However, the disadvantage is that the body is not easy to package, the equipment cost is high, and the operation is complicated. Spark plasma sintering is a new and efficient sintering technology that can ensure better mechanical properties, but its implementation suffers from complex equipment, high energy consumption, and high cost. limited.

Compared with other sintering methods, hot-pressing sintering to prepare h-BN ceramics is generally considered an ideal sintering method. It refers to filling dry powder into a special graphite mold and using double or unidirectional pressure to carry out single-step sintering. A sintering method that axially compresses the mold and at the same time heats it to a certain temperature range to carry out molding and sintering. During the hot-pressing sintering process, the blank is also affected by heating pressure. This additional driving force can destroy the support structure of the flake h-BN card and promote the rearrangement of the h-BN grain size. At the same time, It can effectively reduce the sintering temperature and shorten the sintering time, and finally obtain ceramic products with high density, uniform grain size, and good mechanical properties. The purity of ceramic products can be achieved without adding sintering aids or forming aids.