What are the properties of hot and cold spraying?

Cold spraying is an effective method for generating thick aluminum coatings on magnesium alloy surfaces, which does not require much surface preparation and does not take into account the mechanical or thermal properties of the plated parts. Aluminum coatings have shown resistance to various types of electrical corrosion of magnesium elements. In many cases, battery corrosion protection is only required around steel fasteners, and cold spraying is an innovative technology for localized protection of exposed magnesium surfaces.

Thermal spraying refers to a series of processes in which finely dispersed metallic or non-metallic coating materials are deposited onto the surface of a prepared substrate in a molten or semi-molten state to form a spray deposited layer. It is a technology that uses a certain heat source (such as arc, plasma spraying or combustion flame, etc.) to heat powdered or filamentous metal or non-metallic materials to a molten or semi-molten state, and then spray them to the surface of the pretreated substrate at a certain speed with the help of the flame retention itself or compressed air to form a surface coating with various functions.

Thermal spraying is a kind of surface strengthening technology, which refers to a metal surface processing method in which the molten sprayed material is atomized and sprayed on the surface of the part through high-speed air flow to form a spray coating. We call the special working surface "coating", and the working method of manufacturing the coating is called "thermal spraying", which is a general term for spraying and spray welding using various heat sources.

Specific process: using a certain heat source (such as arc, plasma spraying or combustion flame, etc.) to heat powdered or filamentous metal or non-metallic materials to a molten or semi-molten state, and then spray to the surface of the pretreated substrate at a certain speed with the help of flame retention itself or compressed air to form a surface coating with various functions.

Principle: The coating material can be powder, ribbon, filament, or rod. Fuel gas, electric arc or plasma arc provide the necessary heat to heat the thermal spray material to a plastic or molten state, which is then accelerated by compressed air to impinge a confined particle beam onto the surface of the substrate.

The particles that hit the surface are deformed by stamping, forming laminated sheets that adhere to the prepared surface of the substrate, which then cool and accumulate to form a layered coating. Due to the different coating materials, the coating can achieve high temperature corrosion resistance, anti-wear, heat insulation, anti-electromagnetic wave and other functions.

Difference in effect: cold spray is mostly sedative, anti-inflammatory, and astringent pores; And the hot spray is to open the pores and moisturize.

Differences in use: Generally speaking, normal skin types should choose this method of hot spray, because the hot steam can unclog pores, soften keratin, thoroughly cleanse the skin, increase skin transparency, and allow it to better absorb the nutrients in skin care products.

However, for dark spots, acne, allergies, inflammation, sunburn and other problem skin, it is advisable to choose cold spray for care, because cold steam can play a role in shrinking pores, reducing inflammation and swelling and anti-allergies, and has a certain improvement and effect on the problem.

Cold spray: A more effective method for severe pimples. The so-called cold spray is a special treatment of the solution, which is sprayed on the patient's face in the form of a mist at different frequencies and temperatures depending on the condition. This ** does not cause pain to the patient and feels almost nothing.

The effect of hot spray: hot spray can produce hot steam, which can dredge pores, soften keratin, promote blood circulation, discharge toxins, increase skin permeability, better absorb nutrients, make the face ruddy, and can prevent colds, and have a relieving and dredging effect on patients with respiratory diseases and rhinitis.

The role of spraying: cold spray can play a role in hydration, can also shrink pores and control oil, and has a certain improvement effect on the problem of water shortage. Moreover, the mist sprayed by the cold spray hydrator is very fine, finer than pores and easy to absorb, so it can be used anytime and anywhere, and it can be hydrated anytime, anywhere.

Summary. Dear, I'm glad to answer for you, the problem that is easy to occur in the use of cold spraying is that it is cold spray for a long time, which will dry out and cause certain damage, so you must control the spraying time. Frequent use of cold spray spray will affect the normal function of pores, damage the health of the pores, cold spray will shrink the pores, which is not conducive to the smooth discharge of dirt in the spray, affecting the overall finish and brightness of the spray.

Dear, I'm glad to answer for you, the problem that is easy to occur in the process of cold spraying in the process of use is that it will dry out for a long time, and it will cause certain damage to the branching. Frequent use of cold spray spray will affect the normal function of pores, damage the health of the pores, cold spray will make the pores shrink, which is not conducive to the smooth discharge of dirt in the body, and affect the finish and brightness of the whole body.

Kiss, cold spraying is a surface spraying process, the whole process of metal particles are not melted, the use of compressed air to accelerate metal particles to the critical speed of supersound, metal particles flattened on the surface of the substrate and firmly attached Oh, cold spraying leakage section can achieve particle deposition at low temperature, due to the characteristics of this significant limb search, reflecting the advantages of cold spraying: low spraying working temperature, small thermal impact on spraying particles and substrate. There is basically no oxidation, phase change or grain growth of spraying particles, which is suitable for temperature-sensitive materials, oxidation-sensitive materials and phase change-sensitive materials; The direct advantage of having little thermal impact on the substrate makes the substrate have a wider range of options.

Thermal spraying includes flame spraying, arc spraying, plasma spraying, ** spraying and supersonic flame spraying, their common feature is to use arc, flame, plasma or laser as the heat source, heat the powder to a melted or semi-melted state, and then bond the molten droplets to the surface of the workpiece to form a coating. As a result, there is oxidation, phase change, decarburization or alteration of the physical and chemical properties of the original powder during the thermal spraying process.

and other problems, and at the same time, it will have an adverse thermal effect on the substrate. Lianyi Electromechanical, and the cold spraying process because the powder particles are deposited at a lower temperature, compared with thermal spraying, the biggest advantage is that the spraying working temperature is much lower than all thermal spraying processes, so it has many advantages.

Since cold spraying is the deposition of high-speed moving powder particles onto the substrate, it has many advantages while also has its own disadvantages:

1.It is difficult to deposit coatings of brittle materials, including brittle ceramic materials.

and brittle metal materials cannot be coated by cold spraying.

2.When spraying certain powder particles, the most expensive HE must be used as the carrying working gas to obtain a high-quality coating.

3.Cold spray cannot be diffracted by spray.

It is not possible to paint the surface of parts with complex shapes.