CN105349945A - Magnesium alloy diffusion and permeation technology - Google Patents
Magnesium alloy diffusion and permeation technology Download PDFInfo
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- CN105349945A CN105349945A CN201510715749.9A CN201510715749A CN105349945A CN 105349945 A CN105349945 A CN 105349945A CN 201510715749 A CN201510715749 A CN 201510715749A CN 105349945 A CN105349945 A CN 105349945A
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- magnesium alloy
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C10/00—Solid state diffusion of only metal elements or silicon into metallic material surfaces
- C23C10/28—Solid state diffusion of only metal elements or silicon into metallic material surfaces using solids, e.g. powders, pastes
- C23C10/34—Embedding in a powder mixture, i.e. pack cementation
- C23C10/52—Embedding in a powder mixture, i.e. pack cementation more than one element being diffused in one step
Abstract
The invention discloses a magnesium alloy diffusion and permeation technology. After an oxidation film on the surface of cast and formed magnesium alloy is removed through surface treatment, according to the performance requirement, solid diffusion and permeation of a Ti_Zn coating are carried out on the surface of the magnesium alloy, and the surface mechanical property of the magnesium alloy is improved. The magnesium alloy diffusion and permeation technology comprises the steps of magnesium alloy casting and forming, heat treatment in the early stage, mechanical cleaning, washing, alkaline oil removing, warm water washing, acid neutralizing, acetone ultrasonic cleaning, surface solid diffusion and permeation of Ti_Zn alloy, heat preservation and quality testing. During alkaline oil removing, 8 g/L of sodium carbonate, 15 g/L of sodium phosphate and 10 g/L of sodium silicate are included. According to surface diffusion and permeation technology parameters, the mass percent of Zn powder is 70%, the mass percent of titanium powder is 30%, the grain size is 50 micrometers, temperature is 500-520 DEG C, control precision is +/-1 degree, a temperature controller, thermocouple feedback and resistance wire heating mode is adopted as the temperature control mode, and the heat preservation time is 45-60 min. The technology is simple, the bonding strength of the coating and a magnesium alloy matrix is high, falling is not prone to happening, different kinds of alloy can be coated according to different performance requirements, and the mode is flexible.
Description
Technical field
The present invention relates to a kind of magnesium alloy and expand cementation process.
Background technology
Magnesium alloy has good castibility and dimensional stability, easily processes, and scrap rate is low.Compared with aluminium alloy, magnesium alloy has lower density, dynamic viscosity, fusing point, specific heat capacity and latent heat of phase change (see table 1.2).Under identical fluid state (Reynolds index is equal), the filling velocity of magnesium alloy is much larger than aluminium alloy; Its fusing power consumption is few, and setting rate is fast, and actual die casting period ratio aluminium alloy is short by 50%.In addition, the avidity of magnesium alloy and iron is little, and the ability of solid solution iron is low, therefore not easily sticking to mould, die life is higher than aluminium alloy 2 ~ 3 times.Result of study also shows, processing (mill, the brill) energy of magnesium alloy is only 70% of aluminium alloy.Fact proved, magnesium alloy is a kind of metallic substance being very suitable for die casting, not only can cold house but also can hot chamber diecasting, and magnesium alloy die casting wall thickness can be less than the state of the art of 1.0mm at present.
Magnesium has very high shock-absorbing performance, can be used for repeatedly moving and the component of stroboscopic motion, can absorb its vibrational energy, the prolonged mechanical life-span.Magnesium and magnesium alloys is the alloy that vibration damping can be the highest, also be the metallic substance that weight is the lightest, utilize the vibration damping energy characteristic of this excellence can be widely used on the light portable machine of chain saw, nail gun and so on, and the shell of vibrative machine, motor car engine hood etc.
Magnesium alloy thermal conductivity is good, thermostability is high, in quite wide range of frequency, there is excellent electromagnetic shielding characteristic, the housing of the telecommunications such as notebook computer and mobile phone device can be widely used as, replace inwall nickel plating conventional in the past and copper-plated plastic casing, be conducive to the thin-walled property of electron device, miniaturization.
Magnesium alloy is important aeronautical material, and first lunar rover being delivered to the moon by USSR (Union of Soviet Socialist Republics) rocket manufactures with magnesium alloy.20 years in the past, due to the development of novel material, magnesium alloy consumption declined to some extent, and major cause is that the corrosion stability of magnesium is poor, particularly under oceanic climate condition; In addition, the difficulty in cast magnesium alloys founding is also one of influence factor.But, because the light weight of magnesium alloy, specific tenacity are high and technical improvement in recent years, make it in aircraft industry, still have vital role, be used as the structured material of many aeronautical products, such as Helicopter Main subtracts casing, cabin frame, engine frame, compressor casing, uptake and wheel.Magnesium foundry goods accounts for 2% (aluminium accounts for 6%) in helicopter engine structural weight ratio.
The application of magnesium alloy on automobile starts from 1930's, is mainly used in racing car at that time.But in after which 40 years, the application of magnesium alloy on automobile does not obtain real popularization, and its major cause is: the price of magnesium is high, and a large amount of use can significantly improve auto cost.In addition, the chemical property of magnesium is active, not corrosion-resistant, and it is smelted and smelting technique more complicated; When use temperature raises, the intensity of magnesium significantly declines, and which also limits its range of application.The global energy dilemma that the seventies occurs, is filled with vigor to the recovery of Magnesium Alloy Industry, accelerates the development research of Materials science worker to high-performance magnesium-alloy.1971, beetle (Beetle) the vehicle bicycle magnesium alloy of Volkswagen reached 20kg, altogether consumes 42,000t magnesium, almost accounts for 1/4 of whole the Western countries magnesium output.
After entering the nineties, there is the impetus that maintains sustained and rapid growth in the application of automobile component in Europe, the United States, Deng developed country automotive industry of magnesium alloy pressure-casting.According to the application survey display of calendar year 2001 magnesium alloy die casting on automobile: compared with 1996, whole magnesium alloy die casting market growth 26%, wherein 85.90% in application is used to automotive industry.Therefore, the average annual growth rate of automotive magnesium alloy die casting about 20%.The magnesium alloy total amount that Bayerische Motorne Werke Aktiengeellschaft uses in the automobile and motorcycle of production in 1998 is 687 tonnes, and increasing in calendar year 2001 is 1041 tonnes.The santana bicycle magnesium amount that Shanghai Volkswagen Automobile Corporation is produced is 8.3kg.The bicycle magnesium alloy die casting gross weight of current AudiA6 car reaches 14.2Kg, and the target in its future is that bicycle magnesium alloy die casting gross weight is increased to 50 ~ 80Kg [18J.In current North America market, weight in average is the aluminum metal using 8% (115Kg) in the bicycle of 1500Kg, but only has the magnesium metal of 3.8Kg.In 2002, the magnesium part total amount that North America vehicle uses was 53,000 tonne.Wherein, GM accounts for 55%, Ford and accounts for 30%, Chrysler and account for 15%.Estimate according to expert, if the market value of magnesium remains at low levels and related development work continues always, the year two thousand twenty used the magnesium foundry goods of 90Kg to be possible in the past on each North America vehicle.
Although magnesium and alloy thereof have extremely superior physical and mechanical property, especially its high specific strength becomes the ideal material of automobile and aviation.Unfortunately, magnesium has a series of unfavorable performance to comprise very poor corrosive nature, wear resisting property and creep property and high chemically reactive, and this all hinders the application of magnesium in a lot of field.Ultimate challenge in the application that the application of magnesium is especially outdoor is its poor corrosion resistance.Magnesium and alloy thereof are to electrification (galvanic) corrosion particularly sensitivity, and this will cause serious spot corrosion in metallic surface, thus cause the reduction of mechanical stability and the variation of surface quality.Corrosive nature can be reduced, because the content of the impurity such as iron, nickel and copper is maintained below ultimate value by high pure metal by the employing of high pure metal.The corrosion speed of in commission magnesium house gold obviously can be decreased through the abundant or correctness eliminating bad Composition Design, flux content, surface contamination, counter-electrodes, surface protection plan.
One of the most effective approach corroded is prevented to be exactly coated body material.By placing obstacles between environment and metal, coating can protect matrix.In order to the corrosion protection allowing coating provide enough, coating must be even, and bonding strength is high, self-healing, because may occur the physical injury of coating in application process.Another problem of magnesium alloy is chemically reactive, as long as contact with air or water, an oxidation or hydroxide layer can be formed on surface, and this has a negative impact to the bonding strength of coating and homogeneity.Therefore, for forming a good supercoat at Magnesium and magnesium alloys, preliminary cleaning process is vital!
Many possible coating technologies are applied to magnesium and alloy thereof, to improving corrosive nature when being on active service.But various technology all has self superiority and shortage, is now summarized as follows:
Conversion film technology is by chemistry or electrochemical method, make metallic surface form stable compound rete and do not change a class technology of its metal appearance, its formation method is: by metal works pretreatment solution, by chemistry or electrochemical reaction, make metal to be treated surface occur dissolve and react with treatment soln, form the compound rete of one deck indissoluble on the metal surface.Conversion film has a variety of, divides by chemical process, has phosphatize phosphate coat, chromate passivation film, oxalate film, chemical oxide film etc.
For magnesium alloy, the acid of main employing chromic anhydride or dichromate are the chemistry of aqueous solution process (becoming chromate treating) of main component at present.Magnesium alloy immerses in chromic anhydride acid or dichromate solution can clean its surface, and the mixolimnion formed on the surface of magnesium alloy containing 6 valencys or 3 valency chromic salt and matrix metal, the mixolimnion of this chromic salt has completely cut off the contact between metallic surface and environment, 6 valency chromium have self-repair function and rust inhibition simultaneously, finally improve the solidity to corrosion of magnesium alloy.Therefore, magnesium alloy expects that the corrosion protection ability of chromate conversion coating is better than natural oxide film, can be it and provide good application substrate, but rete is very thin, and containing a large amount of micro-map crackings.In addition, in order to keep the barrier propterty of film, film can not stand high temperature.High temperature can make chromate conversion coating lose crystal water and break, and self-repairability is lost, and Corrosion Protection reduces greatly.But the maximum deficiency of chromate conversion membrane technique is treatment solution is poisonous, larger to the threat of environment and the mankind.The chromium ion of the high pollution contained by treatment solution, can volatilize the toxic gas containing chromium ion in treating processes, threatens the health of operating personnel; On the other hand, the chromium ion in useless treatment solution is not easy sedimentation, could discharge, thus cause the raising greatly of cost after need processing.
Under the pressure of the pressure of environment, chromiumfree conversion process easily becomes the future thrust of chemical conversion processing method.Make some progress now, as phosphate conversion process, stannate conversion processing, phosphoric acid salt one permanganate conversion processing and other conversion processing.Although the impact that these new conversion treatment process and the intelligent conversion processing of chromic acid compare environment reduces greatly, the requirement of friendly process still cannot be reached or when meet the requirement of environmental protection, the quality of conversion film is inferior to chromium conversion film.Therefore the green technique of the nonpollution environment factor such as Chrome-free, without phosphorus and heavy metal free is the developing direction of magnesium alloy chemical conversion processing, also has a lot of research work to do.
With stainless steel, iron, nickel or electroconductibility electrolyzer originally as electrode, with the metal for process for anode, in suitable electrolyte solution, under Controlling Technology parameter is as the condition of voltage, current density and electrolyte solution composition, concentration, temperature and pH value etc., carries out anodic polarization, anode oxidation membrane can be obtained in metallic surface.Anode oxide film has the feature of porous, but these do not penetrate rete.These can adsorbed oil and wax, and make pore closure, porous-film can be used as the desirable bottom of coating.If but anode oxide film is not closed, under oceanic climate, make aperture increase due to galvanic corrosion, therefore must carry out closed HAE method after anodic oxidation is typical anode oxidation processing technique.Although technique film-formation result is good, containing Cr compound in solution, environment and human health are worked the mischief; Though chromate-free in the anodizing liquid of HAE method, processing and after cold wash, needing to carry out aftertreatment with the treatment solution containing sodium dichromate 99.
Since the eighties in 20th century, the requirement due to environmental protection and the control to carcinogenic substance, abroad begin one's study and adopt Chrome-free anodic oxidation to replace chromic acid anodizing.In addition, because magnesium alloy inside exists not homophase, there is the uneven clear defect of electrochemistry in the anode oxide film that Mg alloy surface is formed.
Magnesium and alloy surface thereof must be pollution-free, inviolateness, and do not have the unsalted surface of silicate, oxide compound and intermetallic compound.The cleaning process of magnesium alloy comprises mechanical pretreatment, solvent cleaning or alkaline agent cleaning.After cleaning, many employing chemical treatments carry out pickling or etching, such as conversion processing or anodic oxidation.These process make the surface roughening of magnesium and alloy thereof or modification occur, such organic coating could and surface bonding good.Before Mg alloy castings implements Organic coating, all moisture of foundry goods and air must be removed in order to avoid organic coating produces cavity.In order to obtain the good coating of bonding strength, correct substrate precoated layer is very important.
Producing one of method of precoated layer is the aqueous solution put into by magnesium part containing organic compound.These compounds and hydroxide ion react in metallic surface formation one chemical films, subsequently series reaction occur, allegedly can improve anchoring strength of coating and corrosive nature.More produce precoated layer by conversion processing technology and anodizing technology. be then organic coating provides protection as last line of defense bundle.Sum up, application techniques has the four large functions such as decoration function, provide protection, mark effect and extraordinary effect.For magnesium alloy, the major function of organic coating is between metallic matrix and environment, play effect and the decorative appearance effect of protecting insulating layer.This is because.In application process, various forms of physical damnification all may occur, and this requires the performance that organic coating must have self-healing.The patent display of part research and deciphering, suppresses the coating of corrosion or additive and sacrificial anode compound to make the self-healing of organic coating energy by adding in organic coating.These suppress the material of corrosion to be chromate mostly.
Summary of the invention
The object of the invention is to propose a kind of magnesium alloy and expand cementation process.
For reaching this object, the present invention by the following technical solutions:
A kind of magnesium alloy expands cementation process, magnesium alloy after casting is after the oxide film removing surface through surface treatment, according to performance requriements, Ti_Zn coating is oozed in the solid-state expansion of Mg alloy surface, improve the surface mechanical properties of magnesium alloy, comprising: magnesium alloy cast is shaping---thermal treatment in early stage---mechanical cleaning---washing---alkaline degreasing---warm water cleaning---acid neutralization---acetone ultrasonic cleaning---quality test that Ti_Zn alloy is oozed in surperficial solid-state expansion---insulation---.Alkaline degreasing comprises sodium carbonate 8g/L, sodium phosphate 15/L, water glass 10g/L.Surface is expanded cementation process parameter and is comprised Zn opaque amount 70%, titanium valve quality 30%, granularity 50 μm, and temperature is 500---and 520 degree, control accuracy ± 1 degree, temperature control mode is temperature controller+thermopair feedback+Resistant heating, and soaking time is 45min---60min.
Embodiment
Embodiment 1
A kind of magnesium alloy expands cementation process, magnesium alloy after casting is after the oxide film removing surface through surface treatment, according to performance requriements, Ti_Zn coating is oozed in the solid-state expansion of Mg alloy surface, improve the surface mechanical properties of magnesium alloy, comprising: magnesium alloy cast is shaping---thermal treatment in early stage---mechanical cleaning---washing---alkaline degreasing---warm water cleaning---acid neutralization---acetone ultrasonic cleaning---quality test that Ti_Zn alloy is oozed in surperficial solid-state expansion---insulation---.Magnesium alloy model is AZ91D, and sample dimensions is 30mm × 45mm × 6mm, and alkaline degreasing comprises sodium carbonate 8g/L, sodium phosphate 15/L, water glass 10g/L.Surface is expanded cementation process parameter and is comprised Zn opaque amount 70%, titanium valve quality 30%, granularity 50 μm, and temperature is 500 degree, control accuracy ± 1 degree, and temperature control mode is temperature controller+thermopair feedback+Resistant heating, and soaking time is 45min.
Embodiment 2
A kind of magnesium alloy expands cementation process, magnesium alloy after casting is after the oxide film removing surface through surface treatment, according to performance requriements, Ti_Zn coating is oozed in the solid-state expansion of Mg alloy surface, improve the surface mechanical properties of magnesium alloy, comprising: magnesium alloy cast is shaping---thermal treatment in early stage---mechanical cleaning---washing---alkaline degreasing---warm water cleaning---acid neutralization---acetone ultrasonic cleaning---quality test that Ti_Al alloy is oozed in surperficial solid-state expansion---insulation---.Magnesium alloy model is AM60B, and sample dimensions is diameter 20mm, wall thickness 2mm, and alkaline degreasing comprises sodium carbonate 9g/L, sodium phosphate 10/L, water glass 10g/L.Surface is expanded cementation process parameter and is comprised Al opaque amount 80%, titanium valve quality 20%, granularity 80 μm, and temperature is 52 degree, control accuracy ± 1 degree, and temperature control mode is temperature controller+thermopair feedback+Resistant heating, and soaking time is 60min.
Claims (3)
1. a magnesium alloy expands cementation process, it is characterized in that the magnesium alloy after casting is after the oxide film removing surface through surface treatment, according to performance requriements, Ti_Zn coating is oozed in the solid-state expansion of Mg alloy surface, improve the surface mechanical properties of magnesium alloy, comprising: magnesium alloy cast is shaping---thermal treatment in early stage---mechanical cleaning---washing---alkaline degreasing---warm water cleaning---acid neutralization---acetone ultrasonic cleaning---quality test that Ti_Zn alloy is oozed in surperficial solid-state expansion---insulation---.
2. method according to claim 1, is characterized in that, described alkaline degreasing comprises sodium carbonate 8g/L, sodium phosphate 15/L, water glass 10g/L.
3. method according to claim 1, it is characterized in that, described surface is expanded cementation process parameter and is comprised Zn opaque amount 70%, titanium valve quality 30%, granularity 50 μm, temperature is 500---520 degree, control accuracy ± 1 degree, temperature control mode is temperature controller+thermopair feedback+Resistant heating, and soaking time is 45min---60min.
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| CN201510715749.9A CN105349945A (en) | 2015-10-29 | 2015-10-29 | Magnesium alloy diffusion and permeation technology |
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| CN201510715749.9A CN105349945A (en) | 2015-10-29 | 2015-10-29 | Magnesium alloy diffusion and permeation technology |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108637451A (en) * | 2018-05-28 | 2018-10-12 | 东莞市新玛博创超声波科技有限公司 | A kind of method of low temperature ultrasonic auxiliary magnesium alloy welding |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1614065A (en) * | 2004-09-29 | 2005-05-11 | 上海交通大学 | Preparation of high-strength deforming magnesium alloy |
| CN104152891A (en) * | 2014-08-20 | 2014-11-19 | 太原理工大学 | Method for rapidly forming metallurgical alloy layer on magnesium alloy surface |
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- 2015-10-29 CN CN201510715749.9A patent/CN105349945A/en not_active Withdrawn
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1614065A (en) * | 2004-09-29 | 2005-05-11 | 上海交通大学 | Preparation of high-strength deforming magnesium alloy |
| CN104152891A (en) * | 2014-08-20 | 2014-11-19 | 太原理工大学 | Method for rapidly forming metallurgical alloy layer on magnesium alloy surface |
Non-Patent Citations (1)
| Title |
|---|
| 马幼平等: ""表面扩渗Al，Zn处理对ZM5镁合金性能的影响"", 《稀有金属材料与工程》 * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108637451A (en) * | 2018-05-28 | 2018-10-12 | 东莞市新玛博创超声波科技有限公司 | A kind of method of low temperature ultrasonic auxiliary magnesium alloy welding |
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Application publication date: 20160224 |