Macroscopic organization structure of refractory material is heterogeneous body composed of solid material and gas hole. Porosity is the important factors influencing the products under normal temperature and high temperature performance, especially under the condition of high temperature, is products to the outside world of erosion resistance ability is greatly reduced. Reason of gas hole formation: when products molding, the air in the material is completely ruled out. After material moisture ruled out, leaving space. Raw material calcined is inadequate, some should decomposition of salt is the complete decomposition, should be burning ingredients to burn completely. The material composition is uneven, when high temperature firing, contraction is uneven, etc.
The porosity of refractory can be divided into: closed porosity, closed in the products is not connected with the outside world. Open pores, closed at one end and the other end connected with the outside world, for fluid filling. Cut-through pore, The two sides of the cut-through products, get through for the fluid.
2. Bibulous rate
Bibulous rate is absorbed by all the open pores in the products of water quality and the quality of the dry sample ratio. Because the bibulous rate of determination method is simple, in actual production often used for identifying the quality of raw material calcined. The raw material calcined is the better, the bibulous rate value is the lower.
3. Bulk density
The definition of bulk density is the ratio of dry weight and total volume of products, also known as a volumetric weight. Volume density intuitively reflects the degree of the density of the products, it is an important measure indicator of dense refractory products quality. But in the production of lightweight insulation products, in order to reduce the heat capacity and thermal conductivity, people use various means to reduce the products volume density.
4. True proportion
The quality of dry material and its true volume (not including pore volume) ratio. The true proportion of refractory material, can reflect the material composition of purity or the degree of crystal structure transition, proportion, etc.
The thermal properties
1. Thermal expansion
2. Thermal conductivity
The mechanical properties
1. Compressive strength
2. The high temperature creep