Finishing

ANODIZED

It consists in increasing the natural oxide layer, which increases the natural corrosion resistance of aluminum in a very important way. It is known as anodized to the artificial protection layer that is generated on aluminum by the protective oxide of aluminum, known as alumina. This layer is achieved by means of electrochemical processes, obtaining a greater resistance and durability of aluminum.

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Benefits

  • The anodized layer is harder than the layers obtained by painting with synthetic resins. This property makes it more useful in areas where there is heavy traffic so it is subjected to physical abuse and where abrasive cleaners are used.
  • The anodized can not be peeled or flaked because the layer is part of the base metal.
  • Anodizing gives aluminum an appearance of metallic surface far superior to that which can be achieved with organic paints.

Specifications

Specs Thickness Comments
M1L-A-8625F Unless otherwise specified
Type I 0.00002 to 0.0007 Chromic acid anodizing, conventional coatings produced from chromic acid bath.
Type II 0.00007 to 0.0010 Sulfuric acid anodizing, conventional coatings produced from sulfuric acid bath.
Type III 0.0005 to 0.0045 Hard Anodic Coatings
Class 1 No Dimensioanl Changes Non-dyed.
Class 2 No Dimensioanl Changes Dyed.

COPPER

The most commonly used copper electrolytes are those based on cyanide and sulphate base. The cyanide electrolyte (with potassium or sodium cyanide) hardly contains organic additives, unlike copper acid that requires a variety of important additives and exhaustive control to achieve the properties of hardness, leveling and gloss.
The cyanide copper is the first coating of the multilayer systems with great anticorrosive protection, which are usually made on zamak and / or steel as base materials.
Excellent resistance to corrosion when used under plating. With a variety of processes available, each designed for specific purposes as required.

Benefits

  • Improves electrical properties
  • Improves the resistance to corrosion
  • Its use can not be eliminated, as an element of adhesion
  • Improves deposit adhesion in other metals

Specifications

Specs Thickness Comments
M1L-C-14550B Unless otherwise specified
Class 0 0.001″-0.005″ For heat treatment stop-off
Class I 0.001″ For carburizing and decarburizing shield, also plated through printed circuit boards.
Class 2 0.0005″ As an undercoat for nickel and other platings.
Class 3 0.0002″ To prevent basis metal migration into tin (prevents poisoning solderability).
Class 4 0.0001″ To prevent basis metal migration into tin (prevents poisoning solderability).

TIN

Tin is a good conductor and resistant to corrosion, it helps to improve weldability. Notable among its current applications for use in mechanical parts resistant to friction and corrosion. Tin is not suitable for applications at low temperatures.

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Benefits

  • Excellent lubrication
  • Improve electrical conductivity
  • Corrosion resistance
  • Excellent weldability

Specifications

Specs Thickness Comments
MIL-T-10727C As specified on drawing. Thickness guide (not part of spec.)
as follows:
Type I Electrodeposited. Use ASTM-B-545 as a guideline.
.0001″-.00025″ For contacts and bus bars.
.0002″-.0004″ Flash for soldering.
.0003″ min. To prevent galling and seizing.
.0002-.0006″ Where corrosion resistance is important.
ASTM B545-97
Class A 2.5µm (100µin) Mild service conditions, particularly where the significant surface is shielded from the atmosphere (as in electronic connector housings). To provide corrosion and tarnish resistance where greater thicknsesses may be detrimental to the mechanical operation of the product (for example, small electrical spring contacts and relays). Class A is often used for tin coatings that are not to be soldered, but must function as low-resistance electrical contact surfaces.
Class B 5µm (200µin) Mild service conditions with less severe requirements than class C. Applications are as follows: precoating on solderable basis metals to facilitate the soldering of electrical components; as a surface preparation for protective painting; for antigalling purposes; and as a stopoff in nitriding. Also found on baking pans after reflow.
Class C 8µm (320µin), (10µm (400µin) for steel substrates) Moderate exposure conditions, usually indoors, but more severe than Class B. Examples are electrical hardware (such as cases for relays and coils, transformer cans, screened cages, chassis, frames, and fittings) and for retention of the solderability of solderable articles during storage.
Class D 15µm (600µin), (20µm (800µin) for steel substrates) Severe service, including exposure to dampness and mild corrosion from moderate industrial environments. Examples are fittings for gas meters, automotive accessories (such as air cleaners and oil filters), and in some electronic applications.
Class E 30µm (0.0012 in): Very severe service conditions, including elevated
temperatures, where underlying metal diffusion and intermetallic formation processes are accelerated. Thicknesses of 30 to125 µm (0.0012-0.005 in) may be required if the coating is subject to slowly corrosive liquids or corrosive atmospheres or gasses. Thicker coatings are used for water containers, threaded steel couplings of oil drilling strings, and seacoast atmospheres.
Class F 1.5µm (60µin) Similar to Class A, but for shorter-term contact applications and short shelf-life requirements, subject to purchase approval.

PASSIVE

Used to remove metal impurities on stainless steel surfaces, as well as to increase its resistance to corrosion which is promoted as a natural tendency to surface oxidation. The process purifies the surface and improves the resistance to corrosion. It consists basically of a process in which the surface of the stainless steel of any metallic particle that can initiate a bi-metallic corrosion on the surface is decontaminated, to later promote through a chemical process the creation of a layer of more thickness of oxide of chromium which is created naturally, to achieve a lower reactivity of stainless steel before all kinds of environmental agents.

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Benefits

  • Remove rust
  • Removes remnants of mechanical processes from the surface
  • Increase protection
  • Good diffusion barrier
  • Suitable for Rack and Barrel processes (bulk)
  • Improves corrosion resistance

Specifications

Specs Thickness Comments
QQ-P-35C No dimensional change
Type II No dimensional change Medium temperature nitric acid solution with
sodium dichromate.
Type VI No dimensional change Low temperature nitric acid solution.
Type VII No dimensional change Medium temperature nitric acid solution
Type VIII No dimensional change Medium temperature with high concentration of nitric acid.

SILVER

La Plata is a great electric conductor. The high purity of the deposited silver makes this process suitable for parts focused on all types of applications, from electrical contacts that require a high conductivity and resistance to temperature, to decorative objects.
The silver deposits obtained with this process are of high purity, and have a high hardness combined with an excellent ductility.

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Benefits

  • Excellent ductility and conductivity
  • Hardness
  • Temperature resistance

Specifications

Specs Thickness Comments
QQ-S-365D­ 0.00005″ up to
0.003”
Increasing use in both decorative and engineering fields, including electrical and electronic fields.
Type I Matte.
Type II Semi-bright.
Type III Bright.
Grade A With supplementary tarnish-resistant treatment.
Grade B Without supplementary tarnish-resistant treatment.
ASTM B 700-08 This specification covers requirements for electrodeposited coatings of silver used for engineering purposes that may be mat, bright, or
semi bright and are not less than 98% silver purity.
Grade A Mat
Grade B Bright
Grade C
Grade D Semi-bright
Class N A finish that has had no supplementary tarnish resistant treatment.
Class S A finish that has had a supplementary tarnish resistant treatment.

Shot Blast

This system consists in the cleaning of a surface by the action of a granular abrasive expelled by compressed air through a nozzle.The shot blasting removes all corrosion, including that of the deepest craters without significantly damaging the material. In addition, it provides the surface with a marked finish that serves as an anchor for recoating.
This system consists of the cleaning of a surface by the action of a granular abrasive expelled by compressed air through a nozzle.

Benefits

  • Removes thermally treated scale.
  • Removal of tool brands.
  • Cleaning of metal structures.
  • Preparation of materials for application of coatings.
  • Optimize results.
  • Greater uniformity.
  • Obtain greater anchoring and adhesion of coatings.

ALUMINUM CONVERSION COATING

(Chemical Film)

Chemical coating widely used to give protection to Aluminum. The finish can be applied on aluminum surfaces with color or without color, to form a surface resistant to corrosion.

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Benefits

  • Economic
  • Easy to use and offer a variety of valuable properties to extend the service life of the parties.
  • Very thin layer, does not affect the parts dimensionally.
  • It is used as a primer in painting processes.

Specifications

Specs Thickness Comments
DTL-5541F No Dimensioanl Changes
Class 1A No Dimensioanl Changes Class 1A is used as a corrosion preventative film (unpainted) or to improve adhesion of paint finish systems.
Class 3 No Dimensioanl Changes Class 3 is used as a corrosion preventative for electrical and electronic applications, where low resistance contacts are required.
Type I No Dimensioanl Changes Compositions containing Hexavalent Chromium.
Type II No Dimensioanl Changes Compositions containing no Hexavalent Chromium.

ZINC

This Zinc process is used to prevent oxidation and corrosion of the base material, which is protected and extends its useful life.
In this type of coating, the metal that makes up the layer of suffering is Zinc. The galvanized ones are the most extended and there are several passivates that give them different resistances, mainly in the arrival to white corrosion (zinc oxidation). From the beginning of white corrosion, the greater or lesser duration of the protection will depend directly on the thickness of the coating. In this type of coatings and depending on the type of passivation and thickness, they are guaranteed from 48h in corrosion chamber up to 380h. The most common types in this classification are:

  • The Cincados with transparent or iridescent passivation free of Cr VI (hexavalent chromium).
  • Zinc coatings with passivation or black finish free of Cr VI (hexavalent chromium).

We offer a finish that responds both to the demands of technical zinc coating and decorative finishes for its extraordinary brightness, in a variety of shades and with an adequate anti-corrosion protection, subject to the ASTM B-633 standard.

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zinc2

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Benefits

  • Economic
  • Offering protection even if the surface is slightly damaged
  • Consistent distribution
  • Suitable for Rack and Barrel processes (bulk)
  • Great ductility and adhesion
  • Increase protection
  • Good diffusion barrier
  • Suitable for Rack and Barrel processes (bulk)
  • Improves corrosion resistance

Specifications

Specs Thickness Comments
ASTM B 633-07 No dimensional change The primary use of chromate finishes on zinc is to retard or prevent formation of white corrosion products on zinc surfaces.
Fe / Zn25 SC4 25µm(0.0010″)
(very severe)
Fe/Zn 12 SC3 12µm (0.00050″)
(severe)
Fe / Zn8 SC2 8µm (0.00032″)
Fe / Zn5 SCI 5µm (0.00020″)
(mild)
Type I As plated without supplementary treatment.
Type II With colored chromate treatment.
96h Salt Spray
Type III With colorless chromate treatment.
12h Salt Spray
Type V With colorless passivate.
72h Salt Spray
Type VI With colored passivate
120h Salt Spray