What Is Ion Plating?

There are many types of coating methods used in the modern aviation industry, such as electroplating, spray plating, chemical plating, diffusion, rolling, and overcladding. Many of these coating processes have been mastered and have played a significant role in production. However, the existing coating technology cannot keep up with the rapid development of products, which has prompted people to explore new coating technologies. "Ion plating" is the latest vacuum coating technology developed in the past ten years.

Ion plating is a method in which a gas or an evaporated substance is partially ionized by a gas discharge, and an evaporated substance or a reactant thereof is deposited on a substrate under the bombardment of the gas ions or the evaporated substance ions. These include magnetron sputtering ion plating, reactive ion plating, hollow cathode discharge ion plating (hollow cathode evaporation method),

In the aerospace and aerospace industries, various aircraft, missile, satellite, and spacecraft components often work under complex and harmful conditions. Taking an aircraft as an example, the outer parts such as the wing, the skin of the fuselage, and the landing gear are directly corroded by the atmosphere, water, dust, and chemically active gases contained in the fuel combustion products. The outer parts of seaplanes, especially the body and pontoons, are often eroded by seawater, lake water or river water; the combustion chambers, turbine parts and cylinder piston parts of aircraft engines are also often exposed to high temperatures and gas streams containing acids and other active substances. Oxidation. There are also instrument components such as aviation bearings, miniature power transmission devices, precision gears, potentiometers, etc., which are often subject to varying degrees of friction and wear. To make the above-mentioned various components able to meet the demanding requirements of temperature resistance, corrosion resistance, wear resistance, etc., it is often not enough to simply think of a solution from the structure or material of the component. How to do it? One of the most widely used methods at present is to use a surface coating method to protect the substrate of the component to meet the above requirements. This is just like people wearing different clothes according to different environmental conditions, and coating the parts with a heat-resistant, anti-corrosive or wear-resistant coating as needed.

There are many types of coating methods used in the modern aviation industry, such as electroplating, spray plating, chemical plating, diffusion, rolling, and overcladding. Many of these coating processes have been mastered and have played a significant role in production.

However, the existing coating technology cannot keep up with the rapid development of products, which has prompted people to explore new coating technologies. "Ion plating" is the latest vacuum coating technology developed in the past ten years.

The research on vacuum ion plating technology started in the late 1970s, and was established by the State Planning Commission in 1981. In recent years, domestic and foreign countries attach great importance to environmental protection and clean production. The EU Environmental Protection Directive and the Chinese government have formulated similar ROHS regulations. Therefore, the application of vacuum ion plating technology in industry has received widespread attention from the society. Our unit has held seven appraisal meetings and applied for five patents. A lot of work has been done in terms of project establishment time, research and development depth, coating performance analysis, and industrial production promotion.

Seven appraisal meetings. Research on Aluminizing by Ion Plating (1982); Research on Ionic Decorative Plating of Gold-like Titanium Nitride (TiN) (1982); Research on Ion Aluminum Plating by Magnetron Sputtering (1983); Research on New Ion Chrome Plating Technology (1983) Development of CLD-850 multi-purpose magnetron sputtering ion coating machine (1984); research on new technology of magnetron sputtering ion plating (1985); research of ion plating instead of plating technology and development of special equipment (1986).

Five patents. "High-Energy Magnetron Sputtering Ion Plating Technology"; "Plasma-type Arc Source-Magnetron Sputtering Coating Machine"; "Vacuum Ion Plating Replacement of Brass Parts"; "Bidirectional Ion Plating Magnetron Sputtering instead of Plating Equipment" "The furnace body"; "Steel, zinc-based alloy vacuum ion chromium plating process instead of the current chromium plating process" ^[1]

Ion plating is a new development of vacuum coating technology. In ordinary vacuum coating (also known as vacuum evaporation), the workpiece is clamped in a vacuum cover, and when the high-temperature evaporation source is heated by electricity, the material to be plated, the evaporation material, is melted and evaporated. Due to temperature rise, the particles of the evaporation material get a certain movement

No oil for lubrication

In modern aircraft, aero-engines, or aeronautical instruments, especially in aerospace, such as spacecraft, satellites, many rotating parts require good lubrication, but often due to long-term storage, high ambient temperature or For reasons such as space volatility, ordinary grease lubricants are no longer applicable, and solid lubricants have been proposed instead. Tests show that the solid lubricant film produced by ion plating is better than other existing methods. Not only the adhesion is strong, the coating is thin and uniform, and it does not affect the dimensional accuracy and tolerance of the parts. It is also economical, and a large area can be plated with a little lubricating material. The quality of the lubricating film is also good, the friction coefficient is small, and the service life is long. For example, there is a precision bearing on an artificial satellite that has a working life of only a few minutes before being plated and cannot be used at all; but after ion-plating a solid lubricant film, it can reliably work for thousands of hours in flight. Ion plating can not only plate many kinds of solid lubricating materials at normal temperature, but also plate various kinds of high-temperature solid lubricating materials, and some can even play a good lubricating effect at a temperature of more than eight hundred degrees Celsius. The solid lubricating materials that can be plated are silver, gold, copper, lead, lead-tin alloy, fluoride, etc.

Real gold is not afraid of fire

Aerospace parts, especially many engine parts, often need to work at high temperatures. For example, the operating temperature of turbine blades and guide blades is usually around one thousand degrees Celsius, and some even reach fourteen hundred degrees Celsius. In the mythical novel "Journey to the West", when Sun Wukong was placed in the furnace by Tai Shang Laojun for smelting, I am afraid that he could not reach such a high temperature. Modern aero engine parts work at such a high temperature, it is difficult to meet the requirements simply relying on the properties of the base material itself. So, how can engine parts not be afraid of high temperature ablation? At present, apart from taking measures on the part structure (such as using hollow cooling blades, divergent cooling blades, etc.), most of them need to be protected by heat-resistant plating. Ion plating has many advantages for depositing heat-resistant films. It can be used to plate a variety of high-melting materials, such as aluminum oxide, silicon oxide, beryllium oxide, and thallium alloy. The composition of the alloy plating layer is also relatively easy to control, which is suitable for heat-resistant alloys with complex plating compositions, such as iron chromium aluminum yttrium, cobalt chromium aluminum yttrium, or nickel chromium aluminum yttrium alloy.

Turbine blades are currently the main object of attempting to adopt ion-plated heat-resistant coatings. It is reported that after a blade is plated with a nickel-chromium-aluminum-yttrium alloy by this method, its high-temperature working life is three times longer than aluminum plating. Engine parts suitable for the use of ion-plated heat-resistant coatings also include turbine disks, cylinder piston parts, etc. Some parts can work for thousands of hours at high temperatures after this advanced process.

Metal does not rust

Metal parts are rusted, but if they are coated with an anti-corrosion coating, they can be prevented from rusting. Due to the high density of the coating obtained by ion plating, fewer pinholes, good corrosion resistance, and the ability to deposit many excellent anti-corrosion coatings that have not been able to be deposited so far. Therefore, ion plating is currently the most widely used in the plating of anti-corrosive materials. Such as seaplane wallboards and other external parts, this method can be used to plate anti-corrosion coating to prevent salt spray and seawater corrosion; other materials and parts with aluminum alloy parts can also be used this method to plate aluminum to prevent potential difference corrosion. In addition, with the improvement of aircraft flight speed and altitude and the progress of space exploration, titanium alloys are increasingly used. If cadmium plating is still used to prevent corrosion like aluminum alloy parts, there is a danger of cadmium brittleness in use; Coated with alumina, the requirements can be fully met. However, processes such as electroplating cannot plate this material. Ion plating can make a difference. So far, in addition to alumina, corrosion-resistant materials suitable for ion plating include chromium, titanium, tantalum, and stainless steel. The plated aviation parts are screws, nuts, rivets, pins, conduits, joints, gyro rotors, precision gears, metal sealing rings, etc.

In short, the application potential of ion plating in the aviation industry and other sectors is great. In addition to the above, there are many, such as conductive coatings, hardened films, decorative films, and precision welding, fine sealing, surface repair, etc. .

Ion plating is a new technology that has only been developed in the past ten years or so. It has certain unique advantages, and it is possible to solve some key production problems that were difficult to overcome in the past, so it has great application potential. However, as it has not been around for a long time, there are still many key technical issues to be resolved, such as the control of coating thickness, shielding of non-plated surfaces of workpieces, etc., which need further experimentation. Secondly, the equipment capacity is small, large parts are difficult to plate, and the investment is large. We believe that with further research on this technology, ion plating will be gradually improved and developed, and it will be fully applied and promoted in the aviation industry sector.