Conductive oxidation of aluminum? 20. Conductive oxidation of aluminum?

The anodized film has high hardness and wear resistance, strong adhesion ability, strong adsorption capacity, good corrosion resistance and electrical insulation, and high thermal insulation. Because of these specific properties, it has been widely used in all aspects. The process of using aluminum or aluminum alloy products as the anode and placing them in an electrolyte solution and using electrolysis to form an alumina film on the surface is called anodizing of aluminum and aluminum alloys.

The principle of aluminum anodizing is essentially the principle of water electrolysis. When an electric current is passed, the following reaction will occur: on the cathode, 2H ++2E H2 on the anode, 4OH 4E 2H2O + O2, the precipitated oxygen is not only the oxygen in the molecular state (O2), but also the atomic oxygen (O), and the ionic oxygen (O-2), which is usually expressed as molecular oxygen in the reaction.

Aluminum, which acts as an anode, is oxidized by the oxygen precipitated on it, forming an anhydrous A12O3 film

4a1 + 3o2 = 2a12o3 + 3351j It should be noted that not all of the oxygen produced reacts with aluminum, but some of it is precipitated in the form of gaseous.

Types of anodizing: Anodizing has long been widely used in industry. There are many ways to name different names, but there are several ways to classify them:

According to the current type, it is divided into: direct current anodizing; alternating current anodizing; and pulsed current anodizing that reduces the production time to the required thickness, makes the film thick and uniformly dense, and significantly improves the corrosion resistance.

According to the electrolyte, it is divided into: sulfuric acid, oxalic acid, chromic acid, mixed acid and natural coloring anodic oxygen with sulfo organic acid as the main solutionbr> According to the nature of the film layer, it is divided into:

Anodizing of ordinary films, hard films (thick films), porcelain films, bright modified layers, and barrier layers acting on semiconductors.

The direct current sulfuric acid anodizing method is the most widely used because it has an anodizing treatment suitable for aluminum and most aluminum alloys; The film layer is thicker, hard and wear-resistant, and better corrosion resistance can be obtained after sealing; The film layer is colorless and transparent, with strong adsorption capacity and easy to color; The processing voltage is low, and the power consumption is low; The process does not have to change the voltage cycle, which facilitates continuous production and automation of practical operations.

Is conductive oxidation divided into conductive and non-conductive.

Aluminum itself is electrically conductive. For the conductivity of aluminum, you can verify the conductivity by doing experiments, such as the anodizing treatment of aluminum, which is often used in our physical and chemical fields, which is still more commonly used. Aluminum has brought many benefits to our lives, and it is also a great step forward for human civilization.

Chemical properties of aluminumAluminum is a reactive metal, and a dense oxide film with a thickness of about 50 angstroms (1 angstrom) is immediately formed on the surface of aluminum in dry air, so that aluminum will not be further oxidized and can resist water; However, the powder of aluminum is extremely flammable when mixed with air; Molten aluminium reacts violently with water; Aluminum is amphoteric and highly soluble in strong alkalis and can also be soluble in dilute acids.

Aluminium chloride is an electrolyte.

Alumina is both a covalent compound and an electrolyte. Definition of electrolyte: Compounds that conduct electricity in an aqueous solution or in the molten state are called electrolytes.

The premise of a conductive compound: there are freely moving anions and cations in it. Alumina can ionize cations and anions that move freely in an aqueous solution, so it is an electrolyte and a strong electrolyte.

Aluminum chloride is a colorless transparent crystalline or white yellowish crystalline powder. When aluminum chloride vapor is dissolved in a non-polar solvent or molten state, it exists as a covalent dimer molecule (Al2Cl6).

Soluble in water and many organic solvents. The aqueous solution is acidic. In the presence of aromatic hydrocarbons, a mixture of aluminium chloride and aluminium can be used to synthesize diacrylic (aromatic) metal complexes.

For example, orange diphenylchromium is prepared by Fischer-Hafner synthesis of specific metal halides.

It is difficult to say that the bonds of alumina are theoretically inferred to belong to ionic bonds and covalent bonds. In aqueous solution, they can be ionized, and they are all ionic bonds, such as HCL and AlCl3, which are strong electrolytes in water, but they are covalent compounds in aqueous solution, and their covalent bonds are broken in aqueous solution and can conduct electricity in the molten state, so they must be ionic compounds, and covalent compounds cannot conduct electricity in the molten state. Electrolytes are not all ionic bonded compounds.

Alumina. It's ions.

Compound. Strong electrolytes are essentially good at rolling fingers.

Aqueous solution. All in medium or melted state.

Dianqing cherry blossoms remain.

The Songyun compounds are strong such as ionic compounds.

Polarity. Covalent compounds.

Alumina is one of the former.

So alumina is.

Electrolyte.

It can conduct electricity. Aluminum alloy has low density, but relatively high strength, close to or more than high-quality steel, good plasticity, can be processed into various profiles, has excellent electrical conductivity, thermal conductivity and corrosion resistance, is widely used in industry, and the amount of use is second only to steel.

The conductivity of aluminum is second only to silver, copper and gold, although its conductivity is only 2 3 of copper, but the density is only 1 3 of copper, so the quality of aluminum wire is only half of that of copper wire to transmit the same amount of electricity. The oxide film on the surface of aluminum not only has the ability to resist corrosion, but also has a certain insulation, so aluminum has a wide range of uses in the electrical manufacturing industry, wire and cable industry and radio industry.

Method of surface oxidation of aluminum alloy profiles:

1. Natural oxidation, the aluminum alloy profile will react with the oxygen in the air in the natural environment, and a protective layer of alumina will be formed on the surface, and the internal matrix will continue to react with the oxygen. And this protective layer is transparent, which we call oxide film. The naturally oxidized oxide film is uneven, the color is not good-looking, and the corrosion resistance is not strong.

2. Chemical oxidation, the aluminum alloy profile after degreasing and ash removal on the surface is put into the oxidation solution of oxidant and active agent for reaction to generate a layer of artificial oxide film, the role of the active agent is to make the oxide film partially dissolved in the generation process, resulting in pores, so that the oxidation continues, and the oxide film can be thickened.

3. Anodizing is to put the aluminum profile into an acidic electrolyte solution, as the anode, through high-voltage direct current, so that the anion moves to the anode, and produces new oxygen at the anode and the aluminum alloy of the anode to generate an oxide film. In the electrolyte, the acid can locally dissolve the oxide film, creating pores, so that the oxidation reaction can develop in depth.

Yes.

Ordinary anodizing is white below 20mu, and it will turn gray and dark green when it is greater than 25mu. Anodizing, electrochemical oxidation of metals or alloys. The process of forming an oxide film on aluminum products due to the action of impressed current under the corresponding electrolyte and specific process conditions.

Anodizing usually refers to sulfuric acid anodizing, if not specifically specified.

Aluminum alloy features.

1. Low density: The density of aluminum is about 1 3 of copper (or steel). The low density is very beneficial to the lightweight of ships, vehicles, aerospace vehicles and other means of transportation and buildings, and can also save moving costs and processing costs, reduce costs, and are more widely used in various fields such as industry, construction and civil affairs.

2. Good corrosion resistance and weather resistance: aluminum and aluminum alloy can form a hard and dense oxide film with good corrosion resistance in the atmosphere, and the corrosion resistance of aluminum can be further improved through surface treatment such as electrophoretic painting, powder spraying, and anodizing.

Alumina is an electrolyte.

1. Alumina is an electrolyte, and it is a strong electrolyte.

2. Alumina is not an electrolyte in water, but in a special state, oxygen ions and chloride ions will be separated to achieve the effect of conductive electricity.

3. Alumina is widely used as an electrolyte and is an important substance in chemistry. Electrolytes refer to a class of substances that can produce ions and return well and play a role in conducting electric current.

Main role

1. Ruby.

The main ingredient of sapphire is alumina, which has a different color due to other impurities, and sapphire contains iron oxide.

and titanium oxide.

2. Among the main components of aluminite, alumina, the content of alumina is the highest. Industrially, the aluminite is purified into alumina by the Bayer Process and then converted to aluminium by the Hall-Heroult Process.

3. Aluminum reacts with oxygen in the air to form a dense alumina film covering aluminum exposed to air.

Surface. 4. Aluminum is a good conductor of electricity and heat. Due to its high hardness, alumina is suitable for use as abrasive materials and cutting tools.

5. Alumina powder is often used as a medium for color layer analysis.

In August, scientists working at 3M in the United States developed aluminum and rare earth elements.

The synthetic alloy creates a tempered glass called transparent alumina.

Alumina is an electrolyte. Aluminium oxide, chemical formula Al2O3. It is a high hardness compound, with a leakage point of 2054 and a boiling point of 2980, and ionic crystals that can be ionized at high temperatures, often used in the manufacture of refractory materials.

Electrolytes are compounds that are able to conduct electricity when dissolved in an aqueous solution or in a molten state. According to the degree of ionization, it can be divided into strong electrolyte and weak electrolyte, almost all of which are ionized are strong electrolytes, and only a small part of ionization is weak electrolytes.

Properties: insoluble in water white solid, odorless, tasteless, extremely hard, easy to absorb moisture without deliquescent (burned without hygroscopic). Alumina is a typical amphoteric oxide (corundum is the shape of the hexagonal densest accumulation, is an inert compound, slightly soluble in acid and alkali corrosion resistance), soluble in inorganic acids and alkaline solutions, almost insoluble in water and non-polar organic solvents; relative density (d204); Melting point 2050 .