Hard Anodised Composite Coatings

The APTICOTE 350 range of hard anodised composite coatings make aluminium surfaces as hard as steel. By combining the hardness of aluminium oxide with the lubrication, wear resistance and corrosion protection of fluorocarbon polymers, they impart to the aluminium surface previously unattainable properties.

The particles of the selected polymer are permanently locked within the structure of the newly formed anodised layer, resulting in a harder-than-steel, continuous lubricating polymer/ceramic surface of which the polymeric particles become an integral part.

Properties and Benefits

• Low Friction

  APTICOTE 350 composite hard anodized coatings are invaluable in an un-lubricated situation. The dispersion of polymer within the layer gives low friction throughout the component life reduces wear on the counterface and decreases frictional heating.

• Non-stick/Non-wetting

  APTICOTE 350 composite hard anodising imparts non-stick properties, with reduced drag or torque during initial running. Polymer is also available on the coating surface to provide a start-up and assembly aid. The polymer is both oleophobic and hydrophobic, so the coatings repel water and oil and are self-cleaning. APTICOTE 350F is particularly effective in food applications.

• Uniform Coverage

  Apticote 350 hard anodising provides a completely uniform surface layer of predictable thickness. Component surface growth is approximately 50% of the total coating thickness, so that final dimensions can be accurately predicted. For optimum results, sharp corners should be relieved as far as possible. The benefit to the end-user is reduced machining and grinding costs and improved precision of manufacture.

  Poeton are highly skilled at jigging and fixturing, so that an even coating distribution can be achieved on complex geometrical features, including down long bores, where normal anodised layers will thin.

  However, it should be noted that anodising to a specific final size requires that the as-manufactured dimensions and tolerance band are both closely controlled. Tolerances are additive, so that the final size depends more on the incoming precision than on any small variations in the anodising process. Poeton strongly recommend that parts should be anodised to a specified coating thickness rather than to a defined final size.

• Coating Growth

  Like all anodising processes, as stated above, Apticote 350 grows both in and out from the original surface. Whilst the nominal outward growth is usually taken as 50% of the coating thickness, the precise amount varies with the alloy composition, as shown in the table.

  In the table, the dimensional change is the increase in size at the single surface as a % of the coating thickness, ie the 'out' growth. So, for instance, with the Cu containing alloy, the layer will grow 43% out and 57% in.

• High Wear Resistance

  APTICOTE 350 hard anodized composite coatings provide superb wear protection in sliding and adhesive wear situations. It combines the hardness of the anodic layer with the lubrication properties of the polymeric in-fill, ensuring an extended component life and reduced frictional losses.

  It is ideal for slideways, bearings, calibrators, where low stick-slip is required.

• Substrate materials

  The APTICOTE 350 composite hard anodising process can be applied to a range of aluminium alloys, so that the user can choose the substrate for its strength or corrosion properties. Best results are obtained on alloys in which the Silicon content is below 10% and the Copper content is below 5%.

  Ideal materials for the APTICOTE 350 process are:- HE30 (6082), L65 (2014), Ll 60 (7075), DTD 735 and LM25. (Please ask us for advice prior to selecting the alloy type).

• Corrosion Protection

  Most anodic treatments increase the corrosion resistance of aluminium alloys. However, the unique APTICOTE 350 process seals as well as lubricates the surface, with a dramatic improvement in resistance to acid (to pH 4.0), alkaline (to pH 9.0) or saline environments.

  For maximum corrosion protection you should specify APTICOTE 350C.

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