Hot-press sintered silicon nitride ceramics, known in English asHot Pressed Silicon NitrideHot pressed silicon nitride is made by uniaxially pressing silicon nitride powder (with sintering additives) and heating it at the same time. This process requires special types of presses and molds, and it produces silicon nitride with excellent mechanical properties, but only simple shapes. Since it is not possible to machine hot pressed parts in the raw, diamond grinding is the only way to produce complex geometries. Due to the high costs and production difficulties associated with diamond grinding and hot pressing, their use is usually limited to the production of simple silicon nitride ceramic structural parts in small batches.

Almost zero porosity can be achieved with hot-pressed silicon nitride ceramics sintered by hot pressing, which results in hot-pressed silicon nitride ceramic products with excellent mechanical properties and corrosion resistance even in high-temperature applications.

Silicon nitride ceramics are affected by the powder and sintering process, and there are color variations from batch to batch. In fact, even the same batch of silicon nitride ceramics, there may be differences in color. Silicon nitride ceramic powder is generally divided into two kinds of imported and domestic, imported powder after sintering is usually shown as light gray, while the domestic powder after sintering is usually dark gray, or black.

The density of hot-pressure sintered silicon nitride ceramics is somewhat higher than that of air-pressure sintered silicon nitride ceramics, with the former at 3.3 g/cm³ and the latter at about 3.2 g/cm³.

Thermal conductivity of hot-pressure sintered silicon nitride ceramics is usually in the range of 20~25W/(m・K), which is a bit better than conventional air-pressure sintered silicon nitride ceramics. However, if you want advanced ceramic materials with higher thermal conductivity, there are two other options: a high thermal conductivity silicon nitride ceramic plate with a thermal conductivity between 80 and 100 W/(m・K), and an aluminum nitride ceramic with a thermal conductivity of ≥170 W/(m・K).