Surface treatment is the process of artificially forming a surface layer on the surface of the substrate material with different mechanical, physical and chemical properties of the substrate. The purpose of surface treatment is to meet the product corrosion resistance, wear resistance, decoration or other special functional requirements. For metal castings, we are more commonly used surface treatment methods are, mechanical polishing, chemical treatment, surface heat treatment, spraying surface, surface treatment is the surface of the workpiece is cleaned, swept, deburred, de-oiled, de-oxidized skin and so on.
Basic introduction Chinese name ：Surface treatment Foreign name ：Surface treatment Nature ：Industrial process Method ：Electroplating and so on Introduction, history, method, surface treatment before painting, manual treatment, chemical treatment, mechanical treatment, plasma treatment, technical classification, electrochemical method, chemical method, thermal processing method, vacuum method, other methods, prospects for development, terminology, Introduction Generally speaking, there are two interpretations of surface treatment in China, one is the surface treatment in the broad sense, that is, including pretreatment, plating, painting, chemical oxidation, thermal spraying and many other physical and chemical methods, and the other is the surface treatment in the narrow sense, that is, including sandblasting, polishing, etc., that is, we often say that the pre-treatment part. The following we said is mainly the narrow sense of the surface treatment. surface treatment agent workpiece in the processing, transportation, storage and other processes, the surface is often with oxide skin, rust molding residual sand, welding slag, dust, as well as oil and other dirt. To coatings can be firmly attached to the surface of the workpiece, before painting must be cleaned on the surface of the workpiece, otherwise, not only affects the coating and metal bonding and corrosion resistance, but also make the base metal even with coating protection can continue to corrode, so that the coating peeled off, affecting the mechanical properties and service life of the workpiece. Therefore, the surface treatment of the workpiece before painting is an important guarantee and measure to obtain good quality protective layer and prolong the service life of the product. History Surface treatment belongs to the oldest technology, since there are human beings on the earth, surface treatment is the earliest human mastery of a technology. The life of primitive man was extremely hard, living in groups, in order to survive, they made stone tools, using grinding technology to make stone tools with sharp edges, resulting in a "sharp cut" effect. By the Neolithic era, the stone tools used by primitive people had been ground all over the body, the surface was fine and smooth, focusing on the decorative effect, which had become the mainstream of the era. In the primitive society, as important as grinding stone tools is the original painting technology. Primitive human beings already have a sense of beauty, in the late Paleolithic, they used ore dyes for personal self-indulgence in small articles for painting and coating. To the Neolithic period, the invention of pottery makes the primitive color painting technology develop to the peak, forming the famous color pottery art in history, and opening the prelude to the surface treatment and painting technology. Methods Surface treatment before painting In order to remove all kinds of foreign substances (such as oil, rust, dust, old paint film, etc.) attached to the surface of the object, and to provide a good substrate suitable for painting requirements, so as to ensure that the coating film has a good corrosion resistance, decorative properties and certain special functions, the surface of the object must be pre-treated before painting. People do this kind of work, collectively referred to as pre-painting (surface) treatment or (surface) pretreatment. Manual treatment such as scrapers, wire brushes or grinding wheels. Manual can be removed from the surface of the workpiece rust and oxidized skin, but manual treatment of labor intensity, low productivity, poor quality, cleaning is not complete. Chemical treatment is mainly the use of acidic or alkaline solution and the surface of the workpiece oxides and oil chemical reaction, so that it dissolves in the acidic or alkaline solution to achieve the removal of workpiece surface rust oxide and oil, and then the use of nylon made of brush roll or 304 # stainless steel wire (acid and alkali solution made of steel wire brush roll clean can achieve the purpose. Chemical treatment is adapted to the thin plate parts cleanup, but the disadvantage is: if the time control is not appropriate, even if the addition of corrosion inhibitors, but also can make the steel to produce over-etching phenomenon, for the more complex structural parts and parts with holes, acid solution pickling by acid, immersed in the crevices or holes in the residual acid is difficult to remove completely, if not handled correctly, it will be a workpiece after the corrosion of the hidden trouble, and the chemical is volatile, costly, chemical emissions after treatment Difficulty, if not handled properly, will cause serious pollution to the environment. With the improvement of people's awareness of environmental protection, this treatment method is being replaced by mechanical treatment. Mechanical treatment mainly includes wire brush roller polishing method, shot blasting method and shot blasting method. nylon brush roll polishing method is also the brush roll in the motor drive, brush roll with the rolling movement in the direction of the opposite direction in the upper and lower surfaces of the strip high-speed rotating brush to remove the iron oxide. Brush off the iron oxide skin using a closed cooling water flushing system flushed off. Shot blasting cleaning is to use centrifugal force to accelerate the projectile, ejected to the workpiece for descaling and cleaning method. However, the flexibility of shot blasting is poor, limited by the site, some blindness when cleaning the workpiece, and it is easy to produce dead ends on the inner surface of the workpiece that can not be cleaned. Complex structure of the equipment, wear parts, especially the blade and other parts of the fast wear and tear, maintenance labor hours, high cost, a large investment. Surface treatment with shot blasting, striking force, cleaning effect is obvious. However, shot blasting on the thin plate workpiece processing, easy to make the workpiece deformation, and steel shot blasting to the surface of the workpiece (regardless of shot blasting or shot blasting) so that the metal substrate to produce deformation, due to tetraferric oxide and ferric oxide does not have plasticity, crushing and stripping, and the oil film and its material with the deformation, so the workpiece with oil, shot blasting, shot blasting can not be completely remove the oil. In the existing workpiece surface treatment methods, the best cleaning effect is still sandblasting cleaning. Sand blasting is suitable for workpiece surface requirements of higher cleaning. But China's current general-purpose sand blasting equipment mostly consists of hinged dragon, scraper, head type elevator and other primitive and bulky sand transfer machinery. Users need to build a deep pit and do waterproof layer to device machinery, high construction costs, maintenance workload and maintenance costs are great, sandblasting process produces a large amount of silica dust can not be removed, seriously affecting the health of the operating workers and pollution of the environment. Spraying equipment foreign more than the use of sand suction machine as a conveyor of sand amount of machinery, sand suction machine is actually an oversized vacuum cleaner, with a thicker conveying pipe will be hopper and sand suction machine connected to the line, the sand will be sucked into the storage tank, sand suction machine is characterized by the difficulty of the construction and the process of the bucket lifting machine than a simple, and convenient and easy to control, less need to be maintained, but the power consumption of large sand sucker! At present, there are also several domestic manufacturers specializing in the production of sand suction machine, but the technology is relatively immature, so the vast majority of surface treatment enterprises are still mainly using bucket elevator. Need to do the process of shot blasting factory in the choice of sand transfer equipment and dust removal equipment must take into full account the actual situation of production, try to choose the power relative to the production needs of a larger device, due to the shot blasting to do the industry's general wear and tear faster, long-term use of such and such problems will be a lot of impact on the production, the choice of a larger power of the equipment will greatly reduce the maintenance of future wasted time and cost. Dust removal equipment is not enough power not only to damage the health of workers, but also seriously affect the visibility of the sandblasting room, the dust is not discharged also affect the quality of the sand itself, affecting the surface roughness of the workpiece. Manual sand blasting room should be designed according to the actual situation relative to accommodate the workpiece more spacious space, can not be too constrained or affect the workers manual work, while lighting conditions must be good, for the drier areas can be completely sandblasted in the outdoors. Plasma processing plasma, also known as plasma, is a positively charged positive particles, negative particles (including positive ions, negative ions, electrons, free radicals and various types of active groups, etc.) composed of a collection of which the positive and negative charges are equal to the amount of electricity, so called plasma, is in addition to the solid state, the liquid state, the gaseous state outside of the existence of the substance of the fourth state - plasma state. Plasma surface processor by the plasma generator, gas piping and plasma nozzle and other components, plasma generator produces high-pressure high-frequency energy in the nozzle tube is activated and controlled glow discharge in the generation of low-temperature plasma, plasma with the help of compressed air sprayed to the surface of the workpiece, when the plasma and the surface of the object being processed when they meet, resulting in changes in the object and the chemical reaction. The surface is cleaned, removing hydrocarbon-based dirt, such as grease, auxiliary additives, etc., or producing roughness by etching, or forming a dense crosslinked layer, or introducing oxygen-containing polar groups (hydroxyl, carboxyl), which have the effect of promoting the adhesion of various types of coated materials, and are optimized when bonding and painting are applied. With the same effect, applying the electroplasma to the surface results in a very thin, high-tension coating surface, which facilitates bonding, coating, and printing. There is no need for other machines, chemical treatments, or other strongly acting ingredients to increase adhesion. Plasma surface treatment in the printing and packaging industry 1. to solve the problem of laminating open glue 2. to solve the problem of UV, varnish open glue 3. beverage bottles, jam bottles, adhesive sealing to meet the firmness and reliability of the plasma surface treatment in the field of automotive and shipbuilding 1. automotive seals adhesive surface treatment, adhesive closer, sound insulation, dust 2. automotive lamps adhesive process Automotive lamps bonding process, solid bonding, dustproof, moistureproof 3. automotive interior surface spraying, printing pre-treatment, do not fade, do not lose paint 4. automotive brake pads, oil seals, bumper coating pre-treatment, seamless bonding 5. shipbuilding materials bonding pre-treatment, adhesion is perfect Plasma Surface Finish in Ceramic Surface 1. ceramic coating pre-treatment, without primer, coating firm 2. ceramic glazing pre-treatment, adhesion, adhesion, reliability and reliability. Ceramic glaze pretreatment, adhesion enhancement Plasma surface treatment in the cable industry 1. special cable printing, coding printing effect is good 2. fiber optic cable printing, fastness can be comparable to laser marking 3. cross-fiber printing, printing clear wear-resistant Plasma in the medical and biological materials in the set of 1. human implantable materials to meet the compatibility of the surface treatment of the 2. hydrophilic medical consumables 3. medical equipment disinfection treatment 4. medical catheter surface treatment after the bonding, bonding more firmly Plasma in the textile printing and dyeing industry 1. cellulose fiber treatment to improve the dyeing performance of the dyeing rate 2. protein fiber treatment to increase the hydrophilicity, adsorption 3. synthetic fibers to increase the hygroscopicity of the treatment, to remove static electricity Plasma in the surface treatment of plastics 1. tubing surface treatment, to increase the adhesion of the print 2. toys surface treatment, to facilitate the adhesion of printing 2. toys surface treatment, adhesion, printing, etc. 3. beverage bottle caps, cosmetic surface printing, adhesion 4. daily necessities and household appliances plasma treatment 5. shoes adhesion before treatment, to ensure that the solid does not open the glue Digital Products Plasma Surface Treatment 1. cell phone, notebook shell adhesion, shell does not fall off the paint, the text does not fade 2. cell phone keypad and notebook keyboard adhesion, the keyboard text does not fall off the paint 2. Cell phone keys and laptop keyboard bonding, the keyboard text does not paint 3. cell phone shell and notebook shell coating, do not paint 4. LCD flexible film circuitry bonding, bonding more firmly 5. components bound before processing, to ensure that the adhesion is strong Rubber and Plastic Industry Surface Finishing 1. able to carry out the printing, adhesion, coating, etc. Plasma treatment of glass products before the bonding 1. windshield bonding treatment, bonding more moisture-proof, sound insulation 2. laboratory bacterial petri dishes hydrophilic, adhesion treatment, bacteria production uniform 3. display screen bonding treatment plasma metal surface modification 1. improve the adhesion of the metal surface 2. improve the corrosion resistance of the metal surface 3. increase the hardness of the metal and the wear characteristics of plasma surface modification plasma surface modification 1. Strong> Plasma treatment for daily necessities and household appliances 1. Surface treatment before coating, stronger coating 2. Surface treatment before printing, printing does not fall off 3. Surface treatment before bonding, stable bonding 4. Surface treatment for high-grade furniture, no need for sanding, direct painting, no paint loss Technical Classification Depending on the method used, the surface treatment technology can be categorized into the following types. Electrochemical method This method utilizes an electrode reaction to form a coating on the surface of the workpiece. (a) Electroplating The process of forming a plating on the surface of a workpiece in an electrolyte solution with the workpiece as the cathode under the action of an external current is called electroplating. Plating can be metals, alloys, semiconductors or containing various types of solid particles, such as copper plating, nickel plating and so on. (B) oxidation in the electrolyte solution, the workpiece for the anode, under the action of the external current, so that the surface of the formation of an oxide film layer of the process, known as anodic oxidation, such as aluminum alloy anodic oxidation. Oxidation of steel can be chemical or electrochemical methods. Chemical method is to put the workpiece into the oxidizing solution, relying on the chemical action on the surface of the workpiece to form an oxide film, such as steel bluing treatment. Chemical method This method is no current action, the use of chemical interactions, the formation of coating layer on the surface of the workpiece. One of the main methods is: (a) chemical conversion film processing in the electrolyte solution, metal workpiece in the absence of external current, by the chemical substances in the solution and the workpiece interaction to form a coating on the surface of the process, known as chemical conversion film processing. Such as metal surface bluing, phosphating, passivation, chromium salt treatment. (B) chemical plating in electrolyte solution, the surface of the workpiece by catalytic treatment, no external current action, in solution due to the reduction of chemical substances, the deposition of certain substances on the surface of the workpiece and the formation of plating process, known as chemical plating, such as chemical plating of nickel, chemical plating of copper and so on. Thermal processing method This method is in the high temperature conditions ordered material melting or thermal diffusion, the formation of coatings on the surface of the workpiece. Its main methods are: (a) hot dip plating metal workpiece into the molten metal, so that the surface of the formation of the coating process, known as hot dip plating, such as hot-dip galvanizing, hot-dip aluminum plating. (ii) thermal spraying the molten metal atomization, sprayed on the surface of the workpiece, the formation of the coating process, known as thermal spraying, such as thermal spraying zinc, thermal spraying aluminum, etc.. (C) hot stamping metal foil heated, pressurized to cover the surface of the workpiece to form a coating layer of the process, known as hot stamping, such as hot stamping aluminum foil. (D) chemical heat treatment workpiece and chemical contact, heating, in the high temperature state ordered a certain element into the surface of the workpiece process, known as chemical heat treatment, such as nitriding, carburizing, etc.. (E) Surfacing Welding to weld, so that the molten metal deposited on the surface of the workpiece and the formation of weld layer process, known as surfacing, such as surfacing wear-resistant alloys. Vacuum method This method is in a high vacuum state ordered material vaporization or ionization deposition on the surface of the workpiece and the formation of the coating process. Its main methods are. (a) physical vapor deposition (PVD) under vacuum conditions, the metal gasification into atoms or molecules, or make its ionization into ions, direct deposition to the surface of the workpiece, the formation of the coating process, known as physical vapor deposition, the deposition of particle beams from non-chemical factors, such as evaporation plating sputtering plating, ion plating, etc.. (B) Ion injection under high voltage will be different ions into the surface of the workpiece to make the surface modification process, known as ion injection, such as boron injection. (C) chemical vapor deposition (CVD) low pressure (sometimes also at atmospheric pressure), gaseous substances on the surface of the workpiece due to chemical reactions to generate solid deposited layers of the process, known as chemical vapor deposition, such as vapor deposition of silicon oxide, silicon nitride, and so on. Other methods Mainly mechanical, chemical, electrochemical, physical methods. The main methods are: (a) painting spraying or brushing method, the paint (organic or inorganic) on the surface of the workpiece to form a coating process, known as painting, such as spraying, brushing and so on. (B) impact plating with mechanical impact on the surface of the workpiece to form a coating layer process, known as impact plating, such as impact galvanizing. (C) laser surface treatment with laser on the surface of the workpiece irradiation, so that the structure of the process of change, known as laser surface treatment, such as laser quenching, laser remelting, etc.. (D) superhard film technology with physical or chemical methods in the workpiece surface preparation of superhard film technology, known as superhard film technology. Such as diamond film, cubic boron nitride film. (E) electrophoresis and electrostatic spraying 1, electrophoresis workpiece as an electrode into the conductive water-soluble or water-emulsified paint, paint and another electrode constitute a solution circuit. Under the action of electric field, the paint solution has been dissociated into charged resin ions, cations to the cathode, anions to the anode. These charged resin ions, together with the adsorbed pigment particles electrophoresis to the surface of the workpiece, forming a coating, this process is called electrophoresis. 2, electrostatic spraying in the DC high voltage electric field, atomized negatively charged paint particles directed to the positively charged workpiece, so as to obtain the paint film process, known as static spraying. Prospects for the development of some of the traditional methods of surface treatment, such as welding, thermal spraying, brushing and other processes are often not adapted to the needs of modern industry. Such as some of the temperature is particularly sensitive to the metal parts, the surface of the parts will reach a very high temperature, resulting in parts deformation or cracks, affecting the dimensional accuracy of the parts and normal use, and in serious cases will also lead to shaft fracture; brush ferry although no thermal effects, but the ferry layer thickness can not be too thick, pollution is serious, the set of use is also subject to great restrictions. At present, the western countries for the drawbacks of the above methods developed polymer composite materials on-site surface treatment methods, which are more mature Fushilan technology system. The comprehensive performance of the material and the superiority of machinability at any time, not only to fully meet the requirements of the use of repaired and precision, but also to reduce the impact of vibration in the operation of the equipment to extend the service life. Because the material is "variable" relationship, when the external force impact on the material, the material will be deformed to absorb the external force, and with the expansion and contraction of the bearing or other parts of the expansion and contraction, and always maintain a tight fit with the components, reducing the chances of wear and tear for the wear and tear of large-scale equipment, but also can be used "molds For the wear of large equipment, can also use "mold" or "with parts" for the damaged equipment for on-site repair, to avoid the overall dismantling of equipment, but also to maximize the parts with the size to meet the requirements of production and operation of the equipment, to extend the service life of the equipment, to ensure that the enterprise's safe and continuous production. In the domestic surface treatment of the set, polymer composite materials also play an increasingly important role. Terminology The terminology of surface treatmentBefore painting, remove the substrate surface adhesion or generated foreign matter, in order to improve the adhesion of the substrate surface and coating or give the surface to a certain corrosion-resistant properties of the process, can also be called pre-treatment.
1 mechanical pretreatment mechanical pretreatment
In the coating before, using hand tools, power tools or spraying, shot blasting, granular, etc., to remove the substrate surface of the process of foreign matter.
2 chemical pretreatment chemical pretreatment
Before painting, the use of chemical methods to remove the surface of the substrate or the formation of the conversion film process.
3 electrochemical pretreatment
Before painting, the use of electrochemical methods to remove the surface of the substrate or the formation of the conversion film process.
4 degreasing degreasing
The process of removing oil from the substrate surface.
5 chemical degreasing chemical degreasing
The process of removing oil from the surface of the substrate by chemical means.
6 electrochemical degreasing electrochemical degreasing
The process of removing oil from the surface of the substrate by electrochemical means.
7 soak degreasing soak degreasing
The workpiece will be immersed in the cleaning agent to carry out the cleaning without adding external current.
8 spray degreasing
The process of spraying degreasing agent on the workpiece to remove oil.
9 ultrasonic degreasing ultrasonic degreasing
With the help of ultra-field vibration to accelerate the process of removing oil from the surface of the workpiece.
10 derusting derusting
The process of removing rust products from the surface of the steel substrate.
11 trimming trim
The process of removing burrs, knots, weld slag and sharp edges on the substrate to make it suitable for painting.
12 pickling
The process of using acid to wash away surface rust and rolled skin on the substrate.
13 flame cleaning fiamo cleaning
The process of briefly burning the steel structure with a reducing flame, followed by cleaning with a power wire brush.
14 hand tool cleaning
The process of removing foreign matter from the surface of the substrate using hand tools.
15 power tool cleaning power tool cleaning
The process of removing foreign matter from the surface of the substrate using a power tool.
16 blasting
The use of high-speed abrasive stream impact cleaning and roughening of the substrate surface process.
17 dry blasting dry blasting
The process of cleaning and roughening the surface of the substrate by the impact of a high-speed stream of dry abrasive. The use of vacuum systems around the nozzle to remove the waste abrasive or abrasive chips called vacuum dry blasting.
18 wet blasting wet blasting
The use of abrasive and water mixture of high-speed flow of the impact effect of cleaning and roughening the surface of the process.
19 sand blasting
Sand blasting
The process of cleaning and roughening the surface of a substrate by the impact of a high-speed stream of sand.
20 shot blasting
The process of cleaning and strengthening the substrate surface by the impact of a high-speed shot stream.
21 rusting grade rusting grade
The grading of the degree of rusting on the surface of steel.
22 rusting grade derusting grade
The grading of the degree of removal of rust on the surface of iron and steel.
23 abrasive abrasive
Used as a spray treatment medium of natural or synthetic solid materials.
24 angular sand grit
A kind of abrasive with angular or irregularly shaped particles for jet cleaning.
25 shot shot
A ball-shaped abrasive for jetting.
26 depainting depainting
The process of removing an old, damaged paint film in preparation for repainting.
27 surface conditioning
The process of transforming a surface into a suitable condition that can be successfully handled in a subsequent process.
28 conversion treatment
A chemical or electrochemical process that produces a film consisting of a compound of the metal on the surface of the substrate.
29 phosphating phosphating
The process of forming an insoluble phosphate film on the surface of a base metal using a solution containing phosphoric acid or phosphate.
30 chromate passivation chromating
The process of using an acid solution of hexavalent chromium or trivalent chromium compounds to form a chromate conversion film on the surface of a base metal.
31 passivating passivating
The process of producing a passivated state on the surface of a base metal.
32 integral treatment
Degreasing, descaling or degreasing, descaling and phosphating together.
33 temporary protection
Temporary protection of a surface pretreated substrate surface, before the application of a prescribed coating, when its cleanliness has not changed.