Daman Recommended Surface Treatments
 

ANODIZE

Application: Aluminum parts

• Sulfuric acid anodizing is applied to utilize a 10% to 20% sulfuric acid bath at 60°F to 80°F.  Electrical current (2 to 9 amps per sq. ft.) is passed through the solution to the positively charged aluminum part (Anode).  A reaction takes place on the surface of the aluminum part that changes the aluminum to aluminum oxide.  Aluminum oxide in this form is a crystalline structure that is practically nonconductive.  The reaction will continue, and the film will grow until its dielectric properties do not allow electrical current to continue to pass through the film.  This process produces a nearly clear oxide coating which is usually less than 0.001” thick.  The coating is then sealed to improve corrosion protection or colorfastness when dyed.

• Specifically, this coating is referred to as sulfuric anodize, clear anodize, or Type II anodize. 

• A dye may be used to add color to the process.  Commonly available colors are black, red, or blue.

• Anodizing provides good corrosion protection in mild environments and minimum wear protection. 

ELECTROLESS NICKEL  

Application:  Aluminum or ductile iron parts

• Electroless Nickel is applied by submerging the part in a well-agitated bath which usually operates at between 180°F to 190°F.  The bath chemistry requires closer control than that of most plating baths and is very susceptible to contamination. 

• Electroless Nickel plating differs from electroplated nickel in that the deposition is autocatalytic.  This means that the nickel is deposited on a substrate material without the use of external electrical current. 

• Many of the properties of Electroless Nickel are superior to those achieved by electroplating.  Corrosion and chemical resistance are better, ductility is improved, the deposit is harder (especially after heat treating), and the magnetic properties are different. 

• One of the important features of Electroless Nickel is the ability to obtain deposits of uniform thickness even on confined inside surfaces. 

• To ensure good coating adhesion, every part must be thoroughly cleaned of all dirt, oils, and oxides prior to plating.  This preliminary cleaning process can be more involved than the plating process itself. 

• Many varieties of Electroless Nickel are available.  For the most part, the engineered coatings can be divided into three categories:  low, medium, and high-phosphorus deposits.  The level of phosphorus directly affects how hard and how well the deposit resists corrosion.  The higher phosphorus deposits have very good corrosion resistance but are softer than the low phosphorus deposits.  Conversely, the low phosphorus deposits are harder but not quite as resistant to corrosion.

 

Articles:

• Combat Corrosion with Stainless Steel Mainfolds and Surface Treatments

• Electroless Nickel Available on Standard Products

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Other Surface Treatments

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ALODINE

Application: Aluminum parts

• Alodining is the chemical application of a protective chromate conversion coating. 

• It provides good corrosion protection.  It even protects when scratched.  

• Alodined aluminum withstands salt spray 150-600 hours before forming white corrosion.  

• It provides an excellent electrically conductive surface. 

• Paint sticks to it extremely well. In some cases, it can substitute for primer.  

• Alodining adds no measurable weight and does not alter the dimensions of parts (does not make holes smaller).

FINE ZINC PHOSPHATE WITH PEN DIP SUPER

Application:  Ductile iron parts

• Also known as Phos Dip® 1263, this heavy-duty corrosion resistant zinc phosphate I for ferrous metals. Produces dark, fine grain coatings that average 1000-2000 mg/ft2. 

• Pen Dip® Super is a new rust inhibiting oil with superior water displacing properties. Excellent salt spray and humidity resistance. Flashpoint 120°F.
   

HARDCOAT ANODIZE

Application: Aluminum parts

• Hardcoat anodizing is applied utilizing a 10% to 20% sulfuric acid bath at 30°F to 45°F.  Electrical current (20 to 36 amps per sq. ft.) is passed through the solution to the positively charged aluminum part (Anode). 

• Hardcoat anodize is also referred to as Type III anodize. 

• It produces an oxide coating that is denser and thicker than Type II anodizing.  Film thickness is 3 to 20 times that of chromic or Type II anodizing and because of the film’s density, it produces a hardness of 60 to 65 Rockwell on the C scale. 

• The color of this film varies from light gray to dark olive gray depending on the material’s alloy, temper, and coating thickness.

• Wear resistance is the most frequent reason for specifying Hardcoat anodizing.  However, because Hardcoat is also highly dielectric, it is often used to insulate assembly components. 

• Corrosion resistance is a third reason for using Hardcoat.  At normal film thickness of 0.002,” the coating offers corrosion protection superior to that of other anodic coatings, especially when it is sealed. 

MICRO CRYSTAL MANGANESE PHOSPHATE

Application:  Ductile iron parts

• Also known as Phos Dip® M-22, this is a fine-grained microcrystalline manganese phosphate coating process for ferrous metals to reduce wear and prevent galling of moving parts.

• Reduces friction in bearing applications.

• Coating absorbs and holds oils and lubricants as well as providing corrosion protection. 

 

BLACK OXIDE

Application:  Ductile iron parts

• A tight-knit, microscopic oxide film formed by exposing iron parts to a hot solution of salts.

• The finish created efficiently traps and retains oil. The entrapped oil provides enhanced corrosion resistance.

• Ductile iron may not be black in appearance using this process. Call for more details.

 

PASSIVATION

Application: Stainless Steel parts

• All stainless steel products are passivated to maximize the natural corrosion resistance of the material. 

• Removes surface contamination that can potentially form rust or initiate corrosion.