Nickel is an important metal element, with good mechanical strength, ductility and magnetism, as well as high chemical stability, nickel can withstand high temperature, can be highly polishing and corrosion resistance, widely used in aviation, military, special alloys, batteries, catalysts, magnetic materials and other fields.
With the continuous development of society and the continuous improvement of people's requirements for material application, pure nickel and its alloys have increasingly attracted people's attention, and their importance in military and civil applications continues to highlight. At present, the application of nickel mainly includes the following aspects:
(1) Application of nickel in stainless steel. By adding nickel to steel can significantly improve the corrosion resistance, oxidation resistance, ductility and high temperature strength of steel, so the industrial nickel-containing stainless steel in the total production and application of stainless steel has a very prominent position. This makes the growth of stainless steel production has a very significant impact on the demand for nickel, nickel in the stainless steel field currently accounted for more than half of the total nickel consumption.
The solubility of nickel in α -Fe is 10%, and it can be completely dissolved in γ -Fe. Nickel is solidly dissolved in iron and plays a role in strengthening ferrite, thus improving the tensile strength and hardness of steel, but also improving the corrosion resistance of steel. By improving the quality fraction of nickel in stainless steel can further improve the corrosion resistance of steel, nickel content can reach or close to 30%, but by the worldwide nickel resource tension, nickel price rise and other factors, stainless steel enterprises at home and abroad in order to save costs are looking for new steel. In recent years, more and more studies have been made on the nickel-reduced stainless steel by adding other elements such as N and Mn to replace part of nickel.
(2) Nickel base alloy. Nickel not only has a lot of excellent properties, but also through the addition of other metal elements to form the alloy will appear many super abnormal properties, so that it can have wonderful applications. At present, nickel-based alloys are mainly used in the following types.
One is nickel-based superalloy, it is the late 1930s began to develop a class of nickel content of more than 50%, mainly applied to high temperature conditions, with high strength, oxidation resistance and gas corrosion resistance of the superalloy. In 1941, Nimonic 75(Ni-20Cr-0.4Ti) nickel base alloy was produced in Britain, which became the first country in the world to apply nickel base superalloy. Later, Nimonic 80(Ni-20Cr-2.5Ti-1.3Al) nickel base alloy was made by adding aluminum element. Effectively improve the creep strength.
The second is nickel base corrosion resistant alloy, because nickel is austenitic crystal structure, so nickel base corrosion resistant alloy is austenitic structure. Nickel-based corrosion resistant alloy can be divided into Ni-Cu alloy, Ni-Mo alloy, Ni-Cr alloy and so on. Ni-cu alloy has high strength and no magnetism, and is mainly used in weakly reducing media. Such as Marine structures in the Marine environment, seawater desalination, mariculture, seawater heat exchange, etc. The addition of more than 15% molybdenum in Ni-Mo alloy makes the alloy have high oxidation acid corrosion resistance, which can be used in the flue gas desulfurization device of thermal power plant for environmental protection, as well as waste acid with nitrogen oxides and sulfides, and wastewater treatment, etc. Ni-Cr alloy not only has strong oxidation resistance at high temperature, but also can resist the corrosion of strong oxidizing water solution, so it is very suitable for corrosion resistance in strong acid environment.
In addition, corrosion resistant nickel-based alloys are of great use in energy, petrochemical, food and other fields.
The third is shape memory alloy, which refers to the alloy with shape memory function. At a certain temperature, after the alloy is deformed by force, the external force is removed and then the alloy is heated to a certain temperature, and the alloy will return to its shape before deformation by force, as if it has memory. This material is called memory metal.
Among all the shape memory alloys, ni-Ti base alloy has the best shape memory effect. This kind of alloy is most used in aviation and aerospace fields, such as artificial satellites, space shuttle umbrella antenna, usually shape memory alloy deformation after thousands of times easy to fracture, but with the continuous progress of technology, invented a nickel titanium copper alloy, its deformation times can reach tens of millions of times still will not fracture.
At present, shape memory alloy has been widely used in aviation, electronics, biomedicine, automobile, architecture and other fields, greatly expanding the application range of memory alloy.
The fourth is hydrogen storage alloy, as the name implies, refers to this kind of alloy metal in a certain temperature and pressure conditions, can be a large amount of "absorption" of hydrogen, reaction to generate metal hydride, while releasing heat. When these metal hydrides are heated, they break down again, releasing the hydrogen they contain. Hydrogen storage alloy has the advantages of high safety and low cost compared with traditional cylinder storage hydrogen. After continuous research, the world has developed a variety of hydrogen storage alloy materials, according to the number of elements in the hydrogen storage alloy, there are binary system, ternary system and multivariate system. According to the main metal elements in hydrogen storage alloys, they can be divided into rare earth series, magnesium series,
titanium series,
zirconium series, etc.
Nickel is mainly used in rare earth hydrogen storage materials and magnesium hydrogen storage materials. LaNi5 alloy is the representative of rare earth hydrogen storage materials. The magnesium hydrogen storage alloy is represented by Mg 2 Ni alloy, which has a large hydrogen storage capacity. The addition of nickel can reduce the formation enthalpy of magnesium hydride and improve its kinetic properties. However, the Mg 2 Ni hydrogen storage alloy needs to be above 250℃ to release hydrogen. Based on LaNi 5 alloy and Mg 2 Ni alloy, part of La, Mg and Ni are replaced by adding one or more other alloying elements or using other elements. This leads to the further research and development of hydrogen storage alloys with three or more components, which reduces the cost of hydrogen storage materials and improves their properties. It was found that the addition of Ce and AL to La (0.65-x) CEXCa 1.03Mg1.32Ni(9-Y) AL alloy can effectively improve the hydrogen storage capacity of the alloy.
(3) Nickel is used in electroplating field. Nickel electroplating is a method of depositing a layer of nickel on the surface of metal parts after converting nickel cation into metal nickel by power supply. It can be directly used as the surface coating of the parts, but also can be used for the base before chrome plating, the main purpose is to make the surface of the parts become beautiful and shiny, while increasing the wear resistance and corrosion resistance of the parts, prolong the service life. At present, nickel plating technology has been widely used in machinery, instruments, meters, medical instruments, household appliances and other manufacturing industries. Electroplating a layer of corrosion-resistant nickel on the carbon fiber composite material can protect the carbon fiber composite material from being eroded by solid or liquid particles. With the increase of the thickness of nickel coating, the life of the carbon fiber composite material is obviously prolonged. In recent years, electrodeposition nickel plating based on supercritical carbon dioxide fluid has attracted great attention. Compared with conventional nickel plating technology, the material produced by this technology has better properties and is more environmentally friendly.
Electroless nickel plating technology is a film forming technology, also known as nickelless plating technology, which uses specific metal salts and reducing agents to generate autocatalytic reaction on the surface of the material, so as to precipitate metal onto the surface of the solid substrate and form a metal coating on the surface. In recent years, the research direction of electroless nickel plating is mainly low temperature electroless nickel plating, lead-free and cadmium-free electroless nickel plating, local electroless nickel plating, composite coatings and multiple coatings, etc. The ni-P/nano-sic composite coating was coated on 6061 aluminum alloy by electroless nickel plating. It was found that the corrosion resistance and wear resistance of the composite coating could be enhanced by infiltrating SiC nanoparticles into the composite coating.
(4) Nickel applied to chemical power supply materials. Nickel can be used to produce chemical power supply materials, and chemical power supplies have been used in industrial production, such as cadmium nickel battery, nickel metal hydride battery and zinc nickel battery. The production of cadmium-nickel battery and Ni-Mh battery needs a lot of nickel as raw material. The content of nickel in cadmium nickel battery is 20%, the content of nickel in nickel hydride battery is 27%. Nickel-metal hydride battery, referred to as MH-Ni battery, has high capacity, no memory effect, good charge-discharge performance and other characteristics, compared with the cadmium nickel battery, nickel-metal hydride battery not only power reserve 30% more, but also the weight is smaller than the cadmium nickel battery, cycle service life is also long, more importantly, it is almost no pollution to the environment. Very suitable for notebook computers, camcorders, digital cameras and electric bikes.
Zinc nickel cadmium nickel battery, battery integrated iron nickel batteries and nickel-metal hydride batteries in nickel and zinc nickel zinc electrode in the battery electrode, with long service life and zinc nickel anode anode high capacity of superior performance, zinc nickel batteries with high specific energy, specific power is high, broad temperature range have to work at the same time, no memory effect, low cost and no pollution, etc. Usually the voltage of zinc-nickel battery can reach 1.6V, much higher than the 1.2V of nickel-metal hydride battery, more suitable for the use of traditional 1.5V battery electrical appliances, in digital cameras, flash, electric toys and other electronic products with incomparable advantages.
(5) Nickel for organic synthesis catalyst. Nickel catalyst has strong adsorption capacity for hydrogen, high catalytic activity for hydrogenation reaction, and good thermal stability. It can not only be used as a catalyst in the hydrogenation reaction of unsaturated compounds, such as alkenes, alkynes, diolefin, aromatic hydrocarbons and polymers with unsaturated bonds. It is also a good catalyst for dehydrogenation, oxidation dehalogenation, free radical polymerization, desulfurization, methanation and other reactions.
In addition to nickel catalyst, nickel-iron alloy, nickel-iron oxide and nickel-iron catalyst containing other elements and other nickel-iron based materials, have high catalytic activity for oxygen evolution reaction, can be used as a catalyst for oxygen evolution reaction in water electrolysis process.
(6) Nickel is used for magnetic materials. Nickel is a ferromagnetic metal and an important component of magnetic materials. The commonly used nickel soft magnetic material is a nickel soft magnetic alloy containing about 80% nickel, which is an important iron core material in the electronic industry. Its maximum permeability and initial permeability are high, but its coercivity is low. Hard magnetic materials, also known as permanent magnetic materials, have high remanence magnetic induction, high coercivity, high resistance to demagnetization, and have great application prospects in the fields of transportation, instrumentation and communication. At present, aluminium-nickel-cobalt permanent magnetic material is the best permanent magnetic material with temperature stability, which is a typical representative of nickel permanent magnetic materials. In the 1950 s, aluminum nickel and cobalt permanent magnet almost accounted for more than half of the permanent magnetic material production, later because of the high performance ndfeb permanent magnet materials and development of cheap ferrite magnets, alnico permanent magnet materials, the decrease of the proportion of but since it has good temperature stability and time stability and high temperature resistant properties, So in some special fields, especially in aerospace, the role of al-Ni-Co permanent magnetic materials is still irreplaceable.
Because many properties of permanent magnetic materials will change greatly when the particle size of permanent magnetic materials is reduced to nano scale, the research enthusiasm of micro and nano alloy magnetic materials has been relatively high in recent years.