A variety of different industrial processes enable manufacturers to finish metal parts in order to obtain desired surface characteristics. For example, a surface treatment may modify the exterior appearance of a component, or enhance exterior electrical conductivity.
Anodizing has become a widely-used finishing surface treatment today. Essentially, it transforms the exterior of a metal workpiece to increase the depth of the oxide layer on the surface of the part passively. This process helps prime the area to accept coatings and sealants. It also typically enhances the ability of the part's exterior to resist corrosion.
The Anodizing Process
During anodizing, a metal part serves as the positive terminal of an electrolytic cell. Typically, manufacturers create the cell by attaching a cathode to the inside of a tank containing an acidic electrolyte solution and immersing the metal workpiece in this vat. They pass a direct electrical current through the solution. The electrical current causes the oxide layer on the exterior of the metal part to gradually expand on a microscopic level, producing desired surface changes.
Modern industrial parts manufacturers frequently anodize nonferrous metal components to achieve harder, more porous surfaces. The increase in surface levels of oxides gradually helps harden the exterior of the metal, causing it to become brittler. This process subtly changes the structure of the surface of a workpiece.
Anodizing aluminum permits manufacturers to dye the metal more easily. This surface treatment also enhances corrosion resistance and increases the hardness (but not the strength) of the exterior. Currently manufacturers choose to anodize most aluminum components.
Although industrial parts fabricators have discovered many ways to anodize aluminum, three techniques predominate. They include:
Chromic Acid Anodizing
This method of aluminum anodizing involves submerging the workpiece as the anode in an acidic bath of chromic acid. Since the solution transmits electric currents effectively, this finishing process requires care to prevent industrial accidents. Chromic acid anodizing helps primes aluminum surfaces for subsequent painting.
Sulfuric Acid Anodizing
During sulfuric acid anodizing, a manufacturer utilizes sulfuric acid instead of chromic acid as an electrolysis solution. This process will produce a porous, brittle aluminum oxide surface capable of accepting coatings of dyes and sealants. Sulfuric acid has become a widely used acidic solution for aluminum anodizing today.
Many manufacturers rely on a process called hardcoat anodizing to help anodize aluminum surfaces which will sustain exposure to harsh environments. The finishing process necessitates rigorous controls over the production parameters involved in performing electrolysis in order to achieve a thick surface layer of aluminum oxide. Workpieces which undergo this process may withstand subsequent finishing operations better than untreated components.
Materials And Applications
Anodizing has gained widespread use in many manufacturing settings in which companies produce industrial components. Enterprises large and small can employ this type of finishing process readily:
Although anodizing has gained significance in the fabrication of aluminum components, manufacturers sometimes utilize anodizing to help finish parts composed of other nonferrous metals, as well. Harnessing the process of creating an electrolytic cell does not require advanced technology. Manufacturers do require the capability to generate controlled electrical currents to pass through an acidic solution.
When performing commercial anodizing, however, metal parts fabricators must exercise caution in handling caustic acidic electrolysis solutions, such as sulfuric acid. Manufacturers can obtain tanks of suitable sizes and specialized electrical components to perform electrolysis on nonferrous metal workpieces on a mass production scale. Frequently, anodizing represents merely one of several finishing steps in the completion of a nonferrous metal part.
Numerous applications exist for anodized metal components in the commercial marketplace. Since this surface treatment helps prime workpieces to accept dyes and sealants, it performs an important role in the creation of colored extruded aluminum components, such as decorative fencing and trellises. It also greatly assists jewelry makers seeking to create dyed metal components. This process would permit aluminum can makers to color packaging effectively, too.
The creation of brittle, hardened exterior surfaces on nonferrous metals allows anodizing to play an important role in the generation of parts used in some corrosive or harsh environments. Numerous applications exist for anodizing metal parts generated through the automotive, aviation, aerospace, construction, and electronics sectors. This industrial surface treatment also holds value for consumer goods manufacturing.
For example, anodizing assists manufacturers of metal screws, sockets and other threaded components. By subjecting small aluminum parts to this finishing process, a manufacturer may obtain the ability to dye a metal screw to create a more attractive final assembly without painting. Additionally, anodizing helps harden the surface, potentially increasing the useful lifespan of the product.
Advantages of The Anodizing Process
Both aluminum anodizing and anodizing in general supply important benefits to metal part manufacturers.
- Depending upon the materials used during anodizing, the process may occur comparatively inexpensively. Creating an electrolytic cell does not require advanced technical capabilities.
- Anodizing greatly expands the options for coloring metals such as aluminum. Today many light weight items of jewelry and other fashion accessories e.g. buckles, pins, hair barrettes and metal handbag components, can display colored dyes thanks to this simple surface treatment.
- Some types of anodizing permit aluminum parts to better withstand harsh environments. This discovery has helped reduce construction costs in many industries in which the weight of transporting metal contributes to manufacturing expenditures.
- Anodizing holds great value in hardening the surface of aluminum to enhance the durability of threaded components. Screes and threaded aluminum components may enjoy a longer anticipated useful lifespan as a result of the anodizing process.