Improvement of electroplating pretreatment technology for aluminum and aluminum profiles

Views:1115 Author:Site Editor Publish Time:2020-06-19 11:27:36 Orgin:Site

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I. Introduction

     After electroplating various metals on the surface of aluminum and aluminum profiles, the physical or chemical properties of aluminum and aluminum surfaces can be significantly improved. Due to the combination of curtain wall technology and technology, door and window curtain walls respond to the global call for energy conservation and emission reduction. Intelligent curtain walls, such as solar photovoltaic curtain walls, ventilation duct breathing curtain walls, and wind and rain sensing intelligent curtain walls, will show the unique charm of buildings. Aluminum profiles belong to the coating technology, which adds pre-plating and electroplating process steps on the basis of the conventional titanium plating process. The pre-plating process is to chemically treat the activated plated parts in an aqueous solution of salt and hydrochloric acid. Architectural Curtain Wall The non-load-bearing exterior wall enclosure of a building, usually consisting of a panel and a supporting structure behind it. When aluminum and aluminum profiles are used as conductors, silver plating on the surface can improve the conductivity of the surface or electrical contact parts; copper, nickel or tin is electroplated on the aluminum surface to make it easy to weld; thick tin is electroplated on the aluminum surface to improve its wear resistance. In terms of decoration, in fact, most of them are electroplated.

     For a long time, people have been trying to electroplate aluminum profiles and the surface of aluminum profiles, and have been applied in actual production. However, there are oxides between the aluminum profile and the coating, and the thermal expansion coefficients of the aluminum profile and the aluminum profile and the metal coating are different. The electroplating process of aluminum and aluminum profiles is still in the exploratory stage in terms of surface treatment, and a perfect and mature process has not been formed for a long time. The poor adhesion of the coating is the bottleneck that affects the quality of aluminum profile electroplating and product certification.

     2. Traditional aluminum and aluminum plating

     Aluminum and aluminum profiles can be electrolyzed in the electrolyte to form different coatings, but the coating is not strong and easy to peel off. Therefore, aluminum can be deposited in an aqueous solution containing zinc oxide compounds and then electroplated for research. The development of this teaching method is either a zinc replacement method or a deposition method. It can also be processed on the surface of aluminum and aluminum profiles first, and a layer of very thin porous oxide film can be obtained through the use of anodic oxidation system power supply technology, and then controlled electroplating.

     2.1 Traditional aluminum and aluminum plating process

     The process design process of electroplating technology for aluminum and aluminum profiles consists of three important parts: pre-plating treatment, electroplating, and post-plating treatment. Pre-plating treatment is a key process related to the quality management of products and services of electroplating enterprises. Its main research purpose is to remove the grease on the surface of aluminum and aluminum profiles, and form an oxide film and other dirt in the natural environment.

     The conventional general process is: degreasing - washing - anticorrosion - washing - pickling - washing - activation - washing - primary zinc dipping - washing - galvanizing - washing - secondary zinc dipping - washing - neutral nickel plating - washing - subsequent electroplating .

     There are also studies that use wave anodes to produce oxide films instead of galvanizing processes for subsequent electroplating in enterprises.

     2.2 The traditional pretreatment process

     1. The process design process is long and there are many processes.

     2. The process is complicated and the operating range is narrow, the process parameters must be strictly controlled.

     3. The scope of application of the process is not wide, and the design of the pre-treatment technology for different grades of aluminum profiles cannot be the same, and the pre-treatment method must be able to be adjusted according to the grade of aluminum profiles.

     4. Under the premise of strict management and control of pre-treatment technology, the pass rate of electroplating products is very low. The pass rate of ordinary decorative and electroplating products is 85% to 90%, and the pass rate of functional electroplating is 60%70 %.

     5. The service life of each process solution is short, and the treatment cycle is short.

     Due to the generally insufficient approval of traditional aluminum and aluminum alloy processing in the past, it must be improved.

     3. Improve the general-purpose aluminum and aluminum profiles for electroplating pre-treatment technology

     2-in-1 alkaline degreasing etch - water wash - pickling - water wash - deliming - water wash - alkaline activation - zincate - water wash - neutral nickel plating - water wash - subsequent plating.