Micro arc oxidation machine basic concept:
Micro arc oxidation (Microarc oxidation, MAO, Micro arc anodizing), also known as micro-plasma oxidation (Microplasma oxidation, MPO), which through a combination of electrolyte and corresponding electrical parameters, depended on impact of instantaneous high temperature & pressure generated by arc discharge, in order to grow out of ceramic coating on surface of aluminum, magnesium, titanium and its alloys based on metal oxide-based as priority. In process of micro arc oxidation, chemical oxidation, electrochemical anodizing, plasma oxidation coexist, so the process of forming of ceramic layer is very complex, so far there is not a reasonable model to fully describe the formation of the ceramic layer.Micro arc oxidation processes lead ordinary anodization from Faraday area introduced into high-pressure discharge area, by mean of this, overcome the shortcomings of hard anodizing, which greatly enhancing the overall performance of film.
Combine of micro-arc oxidation coating with substrate has features of solid, compact structure, high toughness, with good wear resistance, corrosion resistance, heat shock and electrical insulation properties. This kind of technique has advantages of simple operation and easy to realize film layer functions adjustment, and process is not complicated, also does not cause environmental pollution, that is a new environment-friendly surface treatment technology, who has broad application prospects in aerospace, machinery, electronics, decoration and other fields.
2, Micro arc oxidation machine principle and features:
Micro arc oxidation or micro plasma surface ceramic technology, refers to under the basis of general anodization, using arc discharge to enhance and active reactions occurring at the anode, resulting in surface of aluminum, titanium, magnesium and its alloy metal as materials workpiece to form quality reinforced ceramic layer. By using dedicated micro arc oxidation power supply to apply voltage on workpiece, to make interaction of parts surface metal and electrolyte solution, then go generate micro arc discharge on workpieces surface, under influence of factors of high temperature, electric field, etc., the metal surface to form a ceramic layer to reach the surface strengthening purposes.
Micro-arc oxidation machine technology features:
(1), Significantly increases materials surface hardness, hardness in 1000 to 2000HV, max. up to 3000HV, even can comparable with hard alloy, the hardness significantly exceed than high carbon steel after heating treatment, heat alloy steel, and high speed tool steel;
(2), Good wear resistance;
(3), Good heat resistance and corrosion resistance. This overcomes fundamental application shortcomes of aluminum, magnesium, titanium material, so the technology has broad application prospects;
(4), Have good insulating properties, insulation resistance up to 100MΩ.
(5), Solution as environmentally friendly and comply with environmental emissions requirements.
(6), Technical process is stable and reliable, simple machinery.
(7), The reaction was carried out at room temperature, easy to operate, easy to master.
(8), Basal body growth ceramic film, combined with a solid, compact and uniform ceramic film.
3, Micro arc oxidation equipment required equipment:
a. Input power:
3 Phase, 380V.
b, Micro arc oxidation power dupply:
Due to high voltage requirements (generally between 510-700V), need customized. Usually with silicon transformer.
Power Output Voltage: 0-750V adjustable;
Power Maximum output current: 5A, 10A, 30A, 50A, 100A, etc. optional.
c, Micro arc oxidation tank and ancillary facilities:
Tank can be used PP, PVC and other materials, reinforced with stainless steel outside. Can be applied with cooling facilities outside or cooling liner.
d, hanging jig and cathode materials:
Jigs can use aluminum or aluminum alloy material, cathode material adopts insoluble metal material, stainless steel is recommended.
Micro arc oxidation bath solution:
Focused on aluminum, magnesium, titanium, zirconium, niobium, thallium and other valve metals (valve metal refers a metal to play electrolytic valve role in the electrolyte). Al and Ti can choose the same solution.
a, Oxidizing fluid density: different liquids have different specific gravity, roughly density ranged from 1.0 to 1.1.
b, Oxidizting solution working voltage: 400V-750V.
c, Current density: different liquids, workpieces have different current density. Roughly about: 0.01-0.1 amperes per square decimeter. But there are also a large current existence, and more than 8 amps per square decimeter.
d, Micro arc oxidation time: 10-60 minutes, the longer time, the more dense of film, but also increase the roughness.
e, Liquid PH: alkaline, PH is usually 8-13.
f. Micro-arc oxidation process:
Degreasing —- Water rinse —- Micro arc oxidation —- DI water washing —- Sealing.