Composition and application of ceramic wet sensor

The constituent ceramic wet sensor of the ceramic wet sensor is composed of metal oxide ceramic, separating sub-type and electronic type. 1 Ion-type wet-sensitive element is a porous ceramic element made of an insulating material. Due to the physical adsorption of water molecules in the micropores, H + is present in wet air, and the electrical conductivity of the element is increased, and two α-Fe2O3 and K2CO3 and ZnO.v2O5.LI2O are divided into two α-Fe2O3 and K2CO3 and ZnO.V2O5.LI2O. The ceramic humidity sensor varies greatly with the humidity resistance of the low wet segment, and the linearity is better in the range of 40% -80% RH, and the high humidity segment is too small. It can be seen that the ceramic humidity sensor has better in normal humidity. The characteristic curve, and in a high wet section, the low wet section curve is distortion, and the nonlinearity is obvious. The moisture absorbing characteristics of the ceramic wet cell is also affected by temperature changes, and temperature compensation is important for measurement accuracy. 2 Electronic wet sensor mainly has an aluminum oxide, and the magnesium oxide synthesis ceramic humidity sensor element is increased and decreased, and the chemical adsorption of molecules is formed by chemical adsorption on the surface of the oxide, and the N-type semiconductor, a p-type semiconductor oxide reaction Positive humidity characteristics and negative humidity characteristics. Alumina and a magnesium oxide humidity sensor, a humidity measurement can be performed at a temperature of 700 ° C or lower. However, the structure is complex, and the heating grating is required to be heated to 700 ° C. The power consumption is demanding, the price is expensive, and the characteristics of the air flow rate will be prevented from changing the characteristics of the air flow, and it is not easy to use in the industry. Ceramic wet sensor is a new type of sensor that has been vigorously developed in recent years. The advantage is that the humidity hysteresis, the adsorbent water vapor capacity is strong, the sensitivity is high, the physical chemical performance is stable; the response speed is fast; the size is small, which is easy to mass production; can be heated, which is beneficial to work in harsh environments. However, due to the porous material, the dust is very much, the daily maintenance is frequent, often requires electric heating to clean and easily affect product quality, easy to affected by humidity, poor margin in low humidity, especially short service life, long-term reliability It is an urgent problem for such humidity sensors. Application ceramic wet sensor for ceramic wet sensor has been widely used in various types of machines, such as humidity meters, air conditioners, humidifiers, dehumidifiers, microwaves, and the like. It is shown in Table 1. Table 1. Main application areas of ceramic wet sensor and use responsibility editor: CC, read full text