1 zinc, aluminum, zinc alloy and low melting point alloy wire
Zinc wire and aluminum wire are the most common and the largest amount of pure metal spray wire, mainly used for bridge, derrick, towers, ships, ports, water conservancy facilities and transportation pipelines and other large steel structure for corrosion protection. They have two main mechanisms for the protection of steel materials: First, with the paint coating corrosion protection mechanism similar to the isolation of corrosive media; Second, through the effective protection of the coating material to achieve the cathode (ie, steel components) protection . This is because the electrode potential of zinc and aluminum is lower than that of iron and steel. When the electrolyte is present, the steel material is anodized, and the steel member is protected from corrosion by cathodic protection.
Adding Al in Zn can improve the corrosion resistance of the coating. At present, in the country has achieved a mass production of ZnAl alloy wire, the common grades for the ZnAl15 alloy wire. Recently, Beijing Nonferrous Metals Research Institute has achieved a higher content of Zn Al20 alloy wire mass production. In addition, AlMg alloy wire and rare earth Al alloy wire has gradually become a hot research unit of related materials development projects.
Tin-based alloy is more commonly used tin-based babbitt alloy (SnSbCu alloy) wire, which is mainly used to repair the sliding bearing pad.
2 Iron-based alloy wire
Fe-based spray wire used in more carbon steel wire, stainless steel wire and heat-resistant iron alloy wire.
Carbon steel wire according to the number of carbon content can be divided into low, medium and high carbon steel wire three categories. The coating made of low and medium carbon steel wire is easy to cut and can be used for dimension recovery of over-tolerance parts. High-carbon steel wire can be used for the preparation of abrasion-resistant coatings on shafts and other parts.
Stainless steel is resistant to atmospheric, acid, alkali, salt and other corrosion of the alloy steel, according to its metallographic structure can be divided into five categories: namely, ferritic stainless steel, martensitic stainless steel, austenitic stainless steel, biphasic Stainless steel and precipitation hardened stainless steel. Among them, the martensite (such as Cr13 type) stainless steel wire and austenitic (such as 18-8 type) stainless steel wire is the two more commonly used sprayed wire. The former can be used as a variety of shaft bearing parts, plungers and sleeves and other parts of the wear-resistant coating; the latter because of the much better than the former corrosion resistance, which are more used in the work environment The surface of the part that corrodes the medium. Such as paper dryer, pump shell, valves and various chemical storage tanks.
FeCrAl alloy is a good high-temperature resistance material, has good resistance to high temperature oxidation, the alloy wire is also sprayed as a spray on the steel material to form high temperature oxidation coating. The kind of material in the early coal-fired power plant boiler heating surface of the coating protection to get more applications in recent years has been gradually anti-high temperature, corrosion resistance better nickel-chromium alloy replaced.
3 Copper and copper alloy wire
Copper wire is mainly used for electrical switches and electronic components of the conductive coating and the statue, handicrafts and other decorative surface of the building cement coating.
Brass in brass is mainly used to repair wear and processing of ultra-poor parts, can also be used as a decorative coating. Brass in the addition of about 1% (mass fraction) of tin, can improve the brass corrosion resistance to seawater, it is called the navy brass, a lot of contact with the water in the piston, sleeve and valve.
Aluminum bronze is twice as strong as normal brass and thus has good corrosion fatigue and wear resistance. It is mainly used in water pump blades, valves and bushings. It can also be used to repair bronze castings and make decorative coatings.
Phosphor bronze and white copper are beautiful yellow and white, mainly used as decorative coating.
Good high temperature resistance material, has good resistance to high temperature oxidation, the alloy wire is also sprayed as a spray material to form a high temperature oxidation coating on steel. The kind of material in the early coal-fired power plant boiler heating surface of the coating protection to get more applications in recent years has been gradually anti-high temperature, corrosion resistance better nickel-chromium alloy replaced.
4 Nickel and nickel alloy wire
NiCr alloy wire is the earliest application of Ni-based alloy wire, as a high-temperature resistance material, this kind of alloy has good resistance to high temperature oxidation. Early use of NiCr alloy Ni80Cr20 series, followed by the emergence of Ni70Cr30 series. At present, by the Beijing Nonferrous Metals Research Institute successfully developed Wcr in 43% to 45% between the high chromium nickel-based alloy wire PS45, has achieved industrial production, and is widely used in China, while some products have been exported to the United States And Japan and other countries. The very high chromium content allows selective oxidation of the coating prepared from this alloy wire in a high temperature environment to form a continuous and dense Cr203 protective film on the surface of the coating to help prevent ingress of corrosive media And the outward diffusion of metal ions within the coating. In addition, tests show that the coating material also has a very good anti-sulfide (including SO2, H2S and sulfate, etc.) corrosion performance, making it ideal for thermal power plant boilers and similar conditions with the parts of the pre-protection .
NiAl alloy wire is another widely used nickel-based alloy wire (see Figure 3). This is mainly used as a combination of arc spraying with the bottom of the alloy wire is also used by the Beijing Institute of Nonferrous Metal Research Institute successfully developed the first (the project won the Beijing Municipal Science and Technology Progress Award). The nominal composition of the wire is Ni95Al5. The bonding strength of the coating can reach 55MPa or more, which is essential for spraying various shafts, plunger, paper dryer and ceramic coating on metal substrate. Monel (NiCu) alloy because of good corrosion resistance is also being used more a Ni-based alloy material. Its corrosion resistance, in the reducing atmosphere than nickel, in the oxidation atmosphere is better than copper, in many media have shown more prominent than the stainless steel corrosion resistance.
5 Composite spray wire
Composite spray wire is the mechanical method of two or more composite materials made of composite material, now known as the powder core material or tubular wire.
The earliest emergence of the composite spray wire by the Beijing Nonferrous Metals Research Institute of successful development of flame spraying with the underlying material - NiAl composite wire. It is the use of powder / tube composite method, a certain proportion of Ni powder and Al powder into the aluminum tube, and then through the appropriate means of reducing the diameter of the deformation process and a special joint made for continuous spraying use §¶3mm ( Or 3.175 mm). The composite wire is a synergistic effect of a typical representative of spray coating materials. During the spraying process, Ni and Al react to form NiAl and Ni3Al compounds, releasing 142.8J and 157.92J of heat, respectively, so that the coating can be formed with a lot of metal is a very strong "micro-metallurgical" combination. Coatings made from NiAl composite filaments have a higher service temperature (430 ¡ã C for the former and 870 ¡ã C for the latter) as compared to the molybdenum wire used as the bonding base material. At the same time, from the material cost point of view, the latter is much more economical than the former. In addition, the NiAl composite wire prepared by the coating containing Ni3A1 and other chemical properties of stable, high temperature strength of the intermetallic compounds can also be directly used as high temperature oxidation and wear of the working layer.
Now use is more of another type of powder / skin composite made of composite wire, powder filler that is added to the metal or alloy as a coating with the band (a strand of carbon steel), through the curl, drawing, etc. Process made of composite spray wire. The method has the advantages of convenient adjustment of powder components, short production period and high efficiency, and is suitable for the development of multiple varieties and small batches, and can also be used for mass production of stereotypes. At present, the powder filler in this kind of composite wire is made of ceramics, cermets such as TiB2 / NiAl composite wire (powder / tube method) and wear-resistant composite wire (powder / skin method) Al203NiCR-Cr3C2Fe (Cr) 3B) Quality wear-resistant powder, while adding a small amount of such as Ni, Al and other alloying elements, help to improve the bonding strength. As the coating prepared by this kind of wire material has the structure of hard phase in the soft matrix, it has good abrasion resistance and is suitable for use as scouring resistant coating. The emergence of such composite wire is a solid alloy wire material is a powerful supplement to solve some of the materials can not be used to prepare the traditional plastic processing technology into a wire problem. Currently. This kind of wire has been widely used in the wear protection of circulating surface fluidized bed boiler heating surface piping, fan impeller and other components in coal-fired power plant.
6 Other sprayed wire
Molybdenum wire: molybdenum melting point (2620 ¡æ) high, recrystallization temperature of about 900 ¡æ, high temperature strength, good processing properties, both heat-resistant coating material, but also heat-resistant hydrochloric acid is the only metal material. Ni-Mo alloy (molybdenum 20% ~ 30%) known as the resistance to hydrochloric acid alloy. The main drawback of molybdenum is oxidation, its oxide (MoO3) melting point (about 780 ¡æ) is low, and volatile, therefore, higher than the melting point of rapid oxidation will be consumed. Molybdenum coating and the combination of superior performance of the steel substrate, previously used as a combination of playing the bottom, has now been nickel-aluminum alloy alternative.
Flexible wire: It is characterized by mixing the powder through rubber, pressing into flexible wire (elastic wire). France, the United States, Russia and other countries in the solution of ceramic powder coating spraying problems, the use of flexible organic wire wrapped package, now in developed countries has been widely used in advanced flame spraying process operations. But the use of rubber and powder evenly mixed into a flexible wire is not yet precedent. This flexible wire is extremely easy to apply and has a uniform powder composition.
