Low-density carbon/carbon heat preservation material oxidation-resistant coating and preparation process thereof

Abstract

Provided is a low-density carbon/carbon heat preservation material oxidation-resistant coating and a preparation process thereof. The oxidation-resistant coating is composed of an inner bottoming coating and an outer coating. The inner bottoming coating is prepared from, by weight, 60-100 parts of aquadag and 0-65 parts of resin and curing agent; the outer coating is prepared from, by weight, 30-60 parts of aquadag, 60-100 parts of resin and curing agent, 2-15 parts of sintering aid and 2-15 parts of adhesive. The preparation process of the low-density carbon/carbon heat preservation material oxidation-resistant coating is further included. The affinity of the low-density carbon/carbon heat preservation material oxidation-resistant coating and a matrix is high, and the potential safety hazards of cracking and stripping of a graphite powder coating are solved. The low-density carbon/carbon heat preservation material oxidation-resistant coating can be used in a high-temperature environment, and has the advantages of being free of cracking and dust overflowing.

Description

technical field [0001] The invention relates to thermal insulation heat field material accessories for crystalline silicon growth equipment, in particular to an anti-oxidation coating of a low-density carbon / carbon thermal insulation material and a preparation process thereof. Background technique [0002] At present, the anti-oxidation technology of low-density carbon / carbon thermal insulation materials is mainly to seal the surface of thermal insulation materials. There are three methods for surface sealing. The first is to paste graphite paper to seal the holes. Slag or shedding is easy to occur during use; the second is to stick carbon cloth on the surface to seal the holes, but because carbon cloth is also a porous structure material, a small amount of corrosive gas (such as SiO vapor) enters the low-density insulation material through the pores of carbon cloth. The interior is still corrosive to the insulation material matrix, which shortens the service life of the ins...

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Problems solved by technology

However, there is still the problem of dust on the surface of the working room under high temperature and negative pressure conditions due to the poor affinity between the coating agent itself and the base material, and the use of adhesives to fix and carbonize materials with a high carbon residue value. The price of Kureha products in Japan is expensive, which is 2 to 3 times that of similar domestic products

[0004] Chinese patent application CN102010231A discloses a method for surface coating of low-density carbon / carbon composite materials, which uses phenolic resin glue and sealing particles (silicon powder and / or graphite powder). Although the process is simple, the 2009 In the invention patent CN100567217C published in 2009, the suspension coating containing graphite powder coating has problems such as long manufacturing cycle caused by subsequent chemical vapor deposition strengthening treatment

However, there are hidden dangers in its sealing agent (silicon powder and / or graphite powder). Silicon powder will react with the matrix fiber at high temperature, damage the matrix fiber, and cause stress concentration to cause coating failure. The graphite powder also exists due to scaly graphite. Due to the flat shape of the particles themselves, the extreme orientation is shown during the brushing process, and interlayer cracks occur during molding, making it difficult to mold.

[0005] In addition, Chinese patent application CN103774435A discloses a method for preparing and using an anti-oxidation coating on the surface of carbon fiber felt. After chemically modifying the matrix resin with an inorganic acid salt, it is used as a carbon source precursor and blended with an inorganic powder. Brush on the surface of carbon fiber insulation felt insulation material, and then prepare the coating through curing, carbonization and high temperature processes. The advantage of this coating is that the process is simple and the cost is low, but it does not solve the problem of powder falling and cracking well. And the boron element that has an impact on the crystal pulling and ingot casting industries due to the introduction of inorganic powder

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