Which is better, hard anodised aluminium or stainless steel?

For modestly stressed parts, hard anodised aluminium is a low-weight alternative. The density of aluminium alloys are roughly one-third those of stainless steel alloys. The coating is hard and corrosion resisting.

Hard Anodising Surface Treatments Ltd provides this treatment on a variety of aluminium parts.

What is anodising in plain English?

When bare aluminium is exposed to oxygen in the air, it reacts to form aluminium oxide at its surface. After a short time, this layer of oxide is too thick for the oxygen to penetrate and react any further as the oxygen has not sufficient energy at normal temperatures and pressure. This oxide layer is relatively chemically stable. Anodising develops on this natural process to make a thicker, denser and harder film on the metal by using electrical force to increase the speed and energy of oxygen molecules hitting the aluminium surface.

Hard Anodising Surface Treatments Ltd provide a range of anodising process, including Hard Anodising, Sulphuric acid anodising and chromic acid anodising.

What are the disadvantages of electroless nickel plating?

Compared to hard anodising, electroless nickel is more expensive per unit volume of coating. ENP materials and their disposal involve more processing.

Like many heavy metals, nickel is an allergen, so ENP has little application in surgical equipment and industries such as food processing.

Hard Anodising Surface Treatments Ltd offers a range of surface treatments including Electroless Nickel Plating.

What does Alocrom do?

Alocrom is a Chromate conversion coating that can be applied to aluminium parts by dipping, spraying, or painting. Alocrom provides corrosion resistance. Alocrom improves paint adhesion and is electrically conductive. Hard Anodising Surface Treatments Ltd offers this treatment to AMS 03-18 and MIL DTL 5541.

What is the difference between anodising and hard anodising?

Hard anodic films form when the electrolyte is near freezing. Additionally, the charge carrier concentration is lower in hard anodising, whilst voltage is high. HA coatings have superior abrasion resistance to SAA coatings.

Hard Anodising causes loss of fatigue strength in highly stressed parts by up to 50%. By sealing in a sodium dichromate solution, one can restore fatigue strength. HA coatings have more fatigue strength loss than SAA coatings.

What is the best way to anodise dielectric materials?

Everything conducts electricity even the vacuum of space…if you put enough of an electric potential difference between two points of a given separation you will get an arc. Add moisture (change the material) and you get a lower dielectric strength (V/m). Hard Anodising has a dielectric strength of about 406 Volts at 50 microns of thickness. All dielectric materials lose their strength with increasing temperature, but haircoat anodising has very high thermal stability compared to other dielectric materials.
For this reason, aluminium components may be used to enclose high-voltage electronic equipment. Earthing points can be achieved by masking off a chosen face of the substrate in the anodic cell, thus leaving that face in metal form.

We are a dedicated provider of specialist metal finishing services, concentrating primarily on the anodising of aluminium.