What do you know about the "ceramic coating" that protects oil and gas?

With the acceleration of industrialization and the increasing problem of environmental pollution, the demand for natural gas, as an efficient clean energy that can reduce environmental pollution, has increased rapidly in recent years. In order to ensure the smooth delivery of natural gas, common equipment in oil and gas fields also needs to be reliable enough.
But for specific equipment such as pipelines, due to the mining and other aspects of the production of certain impurities, these impurities often contain a certain number of solid particles, these sand-containing fluids impact the inner wall of the pipe and cause a certain degree of erosion wear, which ultimately affects normal production and may cause leakage of the pipeline .
in order to minimize economic losses, the most common solution is to apply a wear-resistant coating, mainly using organic coatings. However, organic coating in the actual production of wear-resistant role is relatively limited, and can not play a good protective role. Therefore, the wear-resistant coating represented by ceramic coating began to attract attention.
01, ceramic coating characteristics
(1) ceramic coating can organically the ceramic material wear resistance, high temperature resistance, corrosion resistance and metal processability, strong toughness and other characteristics, to play the comprehensive advantages of the two types of materials, while meeting the mechanical products environmental performance (corrosion resistance, wear resistance, high temperature resistance, etc.) and structural properties (combined strength, toughness) needs to obtain a more ideal composite material;
(2) There are many kinds of materials for the preparation of ceramic coatings, including various carbides, oxides and composite oxides, nitrides, borons and silicides, as well as metal ceramics and plastics, which can also be composite
d;
(4) there are many ways to manufacture ceramic composite powder, the coating composition is easier to adjust,
(5) ceramic coating deposition rate is faster, the thickness of the coating can be controlled as needed, The deposition rate of ceramic coating prepared by thermal spraying technology is faster than that of CVD, PVD, electric spark deposition, etc., and the spray rate of thermal spray is usually 2 to 5 kgh.
thermal spraying technology
02, ceramic coating construction
ceramic coating and metal substation in the physical and chemical properties of the difference, resulting in its and the substation interface in the structure and performance of the mutation, especially the difference between the two line expansion coefficients, in the coating and substation interface to produce a larger residual stress, and residual stress is one of the main reasons for coating shedding. As a result, ceramic coatings are rarely used alone.
currently spray ceramic coating, the metal substate is generally pre-sprayed on a thin layer of metal layer, forming a double-structure coating. The role of metal coating in coating structure is to reduce the large residual stress caused by the difference of wire expansion coefficient between ceramic coating and metal substate, and to increase the binding strength of coating and substate, so this thin layer of metal layer is called bonding layer. At present, the structure of ceramic coating is mostly this double coating structure.
with the increase of the operating temperature of the ceramic coating, the coating is damaged due to the mismatch between the coating and the coefficient of expansion of the metal wire of the substate, which creates a large residual stress in the coating. In order to reduce stress in the coating and improve the high temperature service life of the coating, many researchers have added a transition layer between the ceramic layer and the bonding layer to form a "step coating". The results of the coating performance test show that the step coating can reduce the residual stress in the coating and improve the binding strength and thermal impact resistance of the ceramic coating.
03, ceramic coating application status
but ceramic coating although good use, but not everywhere. Because its preparation and coating process is relatively complex, so to achieve "full armed" is not realistic, generally only for erosion wear more serious bureau components, such as oil and gas pipeline elbows, diameter joints, valves under the wide opening, etc. , can be in its erosion wear concentration area to prepare ceramic coating, is expected to achieve better wear resistance.
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