Matters needing attention in the vacuum sintering process of the sintered mesh filter element

Addtime：2022-08-19 08:17:49 Resource：Zhejiang Zhongmao Pneumatic Co., Ltd.

During the vacuum sintering process of the sintered mesh filter element, three obvious changes in vacuum degree can generally be observed, that is, three large gas discharge processes occur in the cemented carbide sintered body.

The temperature at which the vacuum degree changed significantly for the first time was about 350℃. The main reasons were: First, the gas adsorbed on the particle surface was desorbed under the influence of temperature and negative pressure;

The temperature of the second vacuum degree change is about 1 100 °C. The main reason for the significant change in vacuum degree is that the oxides in the compact are reduced by carbon (the reaction temperatures of WO3, TiO2 and C are 993 °C and 1103 °C, respectively), CO gas is produced.

The temperature of the sintered mesh filter element in the third vacuum degree change generally occurs at about 1350 °C. At this time, the furnace temperature is above the eutectic temperature, and the liquid phase appears in the sintered body. In the vacuum state, the liquid binder phase is prone to volatilization loss. Both theory and practice show that the higher the vacuum degree in the furnace, the higher the sintering temperature, the longer the sintering time, the higher the binder phase content, and the higher the carbon content in the sintered body, the greater the volatilization loss of the binder phase.