The technology of graphite block coated oxide coating is affirmedAdd time：2018/01/31
Graphite crucible with high temperature resistance, low thermal expansion coefficient, resistance to thermal shock resistance strain has certain properties of acid, alkaline solution corrosion resistance strong, with excellent chemical stability, corrosion resistance, so casting in metallurgy, machinery, chemical and other industrial sectors, is widely used for smelting alloy tool steel and nonferrous metals metal and alloy smelting, and has a good technical and economic effect.
The graphite crucible is mainly graphite processing, which is a kind of carbon allotrope, surrounding each carbon atom attached to three other carbon atoms （the arrangement of a plurality of hexagonal honeycomb type） by covalent bond, covalent molecular composition. Most of the graphite crucible is carbon, a part of the air, so that the graphite crucible is prone to oxidation, desquamation and exfoliation at high temperature. A long-term research of a new type of oxidation resistant coating has found that graphite materials start to oxidize at about 500 degrees. With the increase of the temperature of graphite crucible, the oxidation rate presents a geometric increase and oxidation aggravates.
Graphite materials synthetic materials under high temperature including graphite electrode, graphite mold and graphite crucible three, these three kinds of materials of graphite under high temperature, the graphite is prone to oxidation combustion reaction, cause the rubber surface material of carbon layer porosity increase and loose structure, influence the service life. Taking ladle conventional baking as an example, carbon containing （graphite） refractories generally produce more than 15mm of decarburization and loose layer after baking. The decarburization layer quickly corrodes after the steel. The majority of the graphite crucible using high temperature sealing coating, the coating with high temperature resistance, using a special high temperature solution, temperature can reach 1800 DEG C, can long time open flame barbecue, coating materials with nano scale lamellar structure, good compactness, effectively prevent the diffusion of oxygen at high temperature, the hardness can reach 7-8H, hardness higher than the hardness of metals.
High temperature closed coatings paint on graphite crucible to form compact coating. It has strong antirust and corrosion resistance, high temperature oxidation resistance, anti tarnish, wear resistance and other characteristics. High temperature closed coatings are applied to kiln, graphite and metal to prevent oxidation at high temperature. The oxidation rate of graphite crucible can reach more than 95%. The energy saving efficiency of graphite crucible can reach more than 95%.
However, graphite crucible and graphite block plate heated at high temperature, and graphite electrode used in high temperature oxidation environment will undergo partial oxidation due to high temperature arc, which will lead to continuous consumption of graphite crucible, even fracture and damage. The loss rate of graphite crucible will reach 40-60%. The new heat-resistant closed coatings are mainly used for oxidation protection of graphite electrodes, graphite crucibles and graphite parts under high temperature, slowing down the oxidation speed, increasing the material strength and improving the service life. The probability of fracture, breakage and shedding of graphite electrode is lower than that of graphite electrode.
Graphite crucible through anti-oxidation coating impregnation besmear after treatment, the ZS-1011 high temperature graphite coating liquid can penetrate into the pores of graphite crucible, the residual air emptying graphite crucible, forming a layer of antioxidant protective film on the graphite crucible and graphite crucible surface porosity. It is this layer of protective film can effectively isolate the air in direct contact with the graphite crucible and graphite crucible by the oxidation reaction, oxidation resistant coatings of impregnation treatment, no cracking, shedding in high temperature changes, which can effectively retard the oxidation of graphite crucible, prolong the service life of the graphite crucible.
Graphite crucible antioxidant coatings, water-borne inorganic environmental protection coatings, high temperature and room temperature without any volatile substances. The heat-resistant sealing coating itself is acid resistant and alkali resistant, and does not react with quenching medium. It can effectively protect chemical reaction of graphite crucible under high temperature, and effectively prevent graphite crucible from oxidizing at high temperature to more than 95%.