Electroless nickel surface pre-treatment prior to chemical treatment methods.

Published: 15th June 2010
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In electroless nickel plating before the metal surface pre-treatment include: polishing, degreasing, rust removal, activation and other processes commonly used in electroless nickel plating metal plating pre-treatment methods and the like. Grinding, polishing, and other physical methods, we do not discuss. The following introduces some of the chemical treatment.

Degreasing

Degreasing methods can be divided into organic solvent oil, chemical oil.

Organic solvent degreasing degreasing is characterized by fast, non-corrosive metal, but a thorough degreasing is not suitable for use in chemical or electrochemical methods to add oil, commonly used organic solvents: gasoline, kerosene, benzene, ketones some chlorinated paraffins and olefins. Another advantage of organic solvent degreasing or by degreasing solvent can be recycled after use. General is flammable organic solvents, use extra caution.

Chemical degreasing solution is to use alkaline saponification and surfactant on the non-saponifiable oil emulsion, and remove all kinds of oil on the surface of. Chemical degreasing temperature is usually taken in between 60-80 degrees, usually visual artifacts degreasing effect, that surface is completely wetted by water sign of oil completely divisible. In addition to general oil from the NaOH, sodium carbonate, trisodium phosphate, sodium silicate, emulsifiers and other components.

Electrochemical degreasing degreasing cathode and anode sub-degreasing, in the same current, the cathode produces hydrogen degreasing degreasing anode produces oxygen than double the bubble is small and dense, emulsion capacity, oil removal better. But likely to cause hydrogen embrittlement and impurity in the cathode workpiece precipitation phenomenon. Although there is no anodic degreasing But these shortcomings may result in surface oxidation and dissolution. The most commonly used to exchange positive and negative chemical degreasing method. Electrochemical and chemical degreasing degreasing formula similar to formula.

Rust

Rust methods include mechanical, chemical and electrochemical methods.

Mechanical method is surface rust to sand blasting, grinding, polishing roller light or other mechanical treatment, are leveling the surface while removing surface rust.

Rust is a chemical solution with acid or alkali to strong erosion of the metal surface treatment to products rust and erosion by chemical reaction of hydrogen bubbles produced by the process of stripping the role of mechanical removal.

Electrochemical rust is acid or alkaline solution on the cathode or anode metal to remove rust treatment. Rust is a chemical anodic dissolution, electrochemical dissolution and precipitation of the oxygen electrode reaction mechanical stripping the role of bubble removal. Cathode and cathode rust chemical precipitation of dissolved hydrogen to remove the role of mechanical peeling.

Pretreatment for electroless nickel plating rust rust process basically the same process.

Activation

Activation is to enable parts to be fully activated surface, such acid components for the different materials used in acid is different.

Activation of iron and steel parts generally available 10% sulfuric acid or hydrochloric acid to 1:1, the activation of the standard is generally uniform surface emitting tiny bubbles. Stainless steel parts can increase the activation of the acid concentration, and heating for etching. Strictly speaking, stainless steel flash electroless nickel plating should be carried out later in electroless nickel plating, which is notified in an electrolytic nickel or electrolytic copper bottom.

Source:http://www.mhcmp.com/

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