Because there are many in the cement production line equipment and pipeline  internal long-term scour by material or high concentration of dust gas, such as  the vertical mill classifier exports, mill outlet duct, classifier, ball mill,  chute, hopper, under all kinds of valve chamber, damper and pipelines, etc.,  wear resistant ceramic coating has been widely used in the above parts. At  present, the domestic non-metallic wear-resistant materials in cement  enterprises, steel mills, power plants are recognized and applied. Here,  titanium shield technology from the requirement of vertical mill grinding system  transform body, talk about the mechanism of the material.

1. High mechanical strength and toughness. Powder in the vertical mill,  classifier and in transmission pipeline, the speed of around 20 m/s, powder on  the lining and pipe wall vertical compressive stress and parallel direction of  shear stress, and cause their strong erosion and abrasion, continuously decrease  the thickness of the lining, reduce the service life. Lined with long withstand  stress, stress fatigue danger, so must have a good impact toughness, especially  shear stress, it is a major cause of lining damage. So the lining materials have  high mechanical strength and toughness. Because slag in cement production, the  highest hardness value, below on grinding slag is analyzed.

1.1 vertical mill grinding system transform body requirements.

Vertical mill in the production of powder in the high-speed airflow, and the  intense collision and friction lining body, carries on the energy exchange.  Lining body suffered serious impact and erosion, the temperature rise, is easy  to be damaged. This requires lining body has the following properties:

1.2 good wear-resisting performance. Due to the high speed air flow, produce  strong scouring powder transform, must speed up the lining of the wear and tear.  So lining must have good wear resistance, high strength may not wear-resisting,  but must have a high strength wear-resisting. Abrasion resistance not only  depends on the strength and material, but also closely related and material  properties. The hardness of slag in Morse probably level 6, the hardness of  cement clinker is Morse 4 ~ 5 level, which requires the lining material hardness  must be above level 6, otherwise it is impossible to wear. So the lining  materials should within 7 ~ 9 to choose. Usually ionic compounds and covalent  compounds have high hardness, especially covalent compound. This is because the  strong covalent bond for health, its space has a strong directivity, constitute  a space network structure, form a strong combination. Such as silicon carbide,  titanium carbide, diamond, has high hardness. Oxide as an ionic compound, often  part of the oxide of healthy strong between ionic bond and covalent bond, the  healthy strong covalent bond, slightly lower hardness. So the lining should be  in oxide, carbide and boride of choice, so as to achieve a higher wear  resistance.

1.3 a good chemical stability. Vertical mill and pipeline to long-term  contact and slag, slag for CaO - A1203 Si0: series compounds, chemical  composition is commonly: CaO38 % ~ 46%, Si0226 % ~ 42%, A12037 % ~ O %, MgO4 % ~  13%, Fe2O3. 2% ~ 1%, MnO0.1 % ~ 1%, S1 % ~ 2%. Main mineral of C2S, and ICAS.  Can know from the chemical composition and mineralogical, mainly for the  alkaline compound, has much to do with production methods, and often change.  This requires lining has good alkali resistance, can not react with slag. If  reaction and slag formation metamorphic layer, can reduce lining material  performance, wear resistance. At the same time because of the metamorphic layer  is different and original liner expansion coefficient, thermal stress generated  when the temperature changes, cause flake structure, increase the wear and tear  of lining materials. Thus request lining material must have a good chemical  stability.

The theory basis of 2, super wear resistant ceramic coating.

There are a variety of factors, which affect the strength of inorganic  materials. The nature of the material strength is an internal bonding force  between the particles. In order to increase the actual strength of inorganic  materials to the theory of strength of materials science and technology workers  have long a lot of research, make numerous experiments. From the material  deformation and fracture analysis shows that under the condition of the  stability of crystal structure, control has three main parameters in the  strength of materials, the modulus of elasticity, fracture surface energy E feet  and crack size C. E is a structure sensitive parameters, only related to the  performance of the material; R related to the microstructure and grain boundary  of main and material, associativity, and flaws; Crack size C is a control main  parameters of strength. So to improve strength and toughness of materials,  mainly from to eliminate defects and improve the interface, should be taken to  stop crack propagation.

2.1 choose the raw materials with high elastic modulus, and improve the  material hardness and wear resistance. Elastic modulus E is an important  material constant, is a sign of interatomic bonding strength, is actually the  interatomic bonding force at any point on the curve slope of the curve. Covalent  bonds, ionic bonds combined with crystals, due to the strong bonding force,  usually have higher elastic modulus. Molecular bond binding force is weak, so  the elastic modulus is smaller. And modulus of elasticity is related to the  distance between the atoms. Can know from the above, in order to get high  strength wear resistant material, should choose the ionic and covalent  compounds, such as oxide, nitride, carbide and boride and corundum, dense  tabular corundum, corundum, silicon carbide, titanium carbide, titanium boride.  Zirconium boride, etc are often used as abrasive, widely used in abrasive  industry.

2.2 should form crystallite, dense microstructure. In order to eliminate the  defects and improve the integrity of the crystal, fine, dense, uniform, pure is  an important direction of current ceramic development, emerged in recent years  many microcrystalline, high density, high purity of ceramic material, such as  hot pressing silicon nitride ceramics, the density is close to the theoretical  value, almost without air hole, has high mechanical strength and wear  resistance, is a traditional ceramic. Especially in recent years, the emergence  of various kinds of fiber and beard, complete with crystal structure, almost no  defects, strength can improve an order of magnitude. Therefore, in the design of  super wear resistant ceramic coating, should give full consideration to the  structure of the material, try to control the content of stomatal and improve  casting density, refine the crystal growth of raw material, form the crystallite  structure, increase the integrity of the crystal.

2.3 the steel fiber reinforced and metal mesh reinforced double reinforcement  mechanism. In order to improve the wear resistance of the material and  structural strength, improve the service life of the super wear resistant  material, reinforced MC resistance to slag erosion of the material caused by the  high-speed mechanical shock and wear, reduce material fatigue damage under  long-term stress condition, should strengthen measures, improve the structure of  the material, optimize its performance. Fiber reinforced have obvious effect,  simple operation, the characteristics of low cost, has been widely used in the  material design. And metal mesh reinforced and toughening, and large area is  used in the cement industry, two methods of compound will further improve the  toughness of the material. The physics principle of steel fiber reinforced tells  us that as the rivet fiber join, the toughness of the material will increase  significantly, the reason is that the introduction of plastic mechanism, and  improved the deformation mechanism of wear resistant material, effectively  improve the material resistance caused by the stress fatigue spalling and  impellers, so as to improve the toughness of the material.

2.4 with fine particles reinforced lining body mechanical strength. When  particles in ceramic material with high strength, material to resist stress  induced crack expansion will be obvious inhibition. Crack extension in under the  action of stress when you meet the particles because the particles of high  intensity and small expansion coefficient, crack was "nail" live, to continue to  expand must require more energy to penetrate particles or crack deflection,  increase the interface area, thus increasing the consumption of energy, improve  the material strength and toughness. After joining particles, material elastic  modulus and shear modulus are increased, the strength and wear resistance are  improved significantly, can increase the service life of wear resistant  material, reduce the production cost.

2.5 the strength and toughness of chemical materials. In order to improve the  strength of the wear resistant ceramic coating curing period and promote binder  hydration process, need to apply on the face of the material curing agent. Must  design a new curing agent, the curing agent is a kind of chemical coating, it  adopt the way of ion exchange, make the surface of the molar volume is larger  than the internal, because of the large surface volume expansion is limited by  internal material, produce two to compressive stress state, so as to improve the  yield strength and fracture toughness of materials. Is usually in a big ion  exchange small ions, due to the displacement is affected by diffusion and  charged ions, pressure layer thickness is limited. Chemical reinforcement is an  important direction in the development of modern materials, have very strong  maneuverability, and very effective.