Finishing

ANODIZED

The anodizing process consists of the formation of an oxide film, which grows from the base metal as an integral part of the metal and when properly applied gives the aluminum a tough, corrosion and abrasion resistant appearance. Coating with excellent wear properties. This porous coating can also be colored using various methods. Many acidic solutions can be used for anodizing, but sulfuric acid solutions are by far the most common.

By balancing the conditions used in the anodizing process, oxides with almost all the desired properties can be produced, from the fine oxides used in decorative applications to the extremely hard and wear resistant oxides used in engineering applications (hard coating).

Benefits

  • Resistant to corrosion and abrasion.
  • Higher surface harness of aluminum compared to synthetic resin paint.
  • Provides a metallic surface appearance far superior to what can be archieved with organic paints.
Specs Thickness Comments
MIL-A-8625F Unless otherwise specified  
Type II 0.00007 to 0.0010 Sulfuric acid anodizing, conventional coatings produced from sulfuric acid bath.
Class 1 No Dimensioanl Changes Non-dyed.
Class 2 No Dimensioanl Changes Dyed.
ASTMB580   Hard coatings may vary in thickness from 12µm to more than 100µm. if the thickness of type a is not specified, it shall be 50 µm min. type a coatings will not be sealed unless so specified.
Type A 50µm     (0.0020″) Engineering Hard Coat
Type B 18µm     (0.00072″) Architectural Class I
Type C 10µm     (0.00040″) Architectural Class II
Type D 8µm       (0.00032″) Automotive-Exterior
Type E 5.0µm    (0.00020″) Interior-Moderate Abrasion
Type F 3µm       (0.00012″) Interior-Limited Abrasion

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
Specs Thickness Comments
MIL-A-14550B Unless otherwise specified  
Class 0 0.001” – 0.005” For heat treatment stop-off
Class 1 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 improve weldability. It should be noted among its current applications for use in mechanical parts resistant to friction and corrosion. The characteristics of weldability, resistance to corrosion and leveling are essentially the same in glossy or matte plating.

Benefits

  • Improves electrical conductivity.
  • Resistance to corrosion.
  • Excellent weldability.
  • Provide anti-galling properties.
Specs Thickness Comments
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.
Matte Tin Electrodeposits   Coatings with a matte appearance are obtained from tin plating baths (stannate,
sulfate, methylsulfonate, and fluoborate) used without the addition of any brightening agents. However, all matte baths (except for stannate baths) do require the addition of grainrefiners, and often of other additives in order to produce the desired matte finish.
Bright Tin Electrodeposits   Bright coatings are obtained when proprietary brightening agents are used in specific
bright tin plating baths.

NICKEL

Nickel plating is one of the most versatile surface finishing processes available on the market, having a broad spectrum of end uses spanning decoration, engineering, and electroforming applications. Nickel coatings for engineering purposes are usually prepared from solutions that deposit a layer of nickel on a substrate, in order to increase its resistance to oxidation, corrosion and / or improve its physical appearance. Nickel is capable of giving parts a homogeneous finish, its resistance, weldability, magnetic and other properties may be relevant in specific applications. Coatings of this origin are bright protectors.

Benefits

  • Wear resistance.
  • Protection against corrosion.
  • Low coefficient of friction.
  • Controllable internal mechanical forces.
Specs Thickness Comments
ASTM B 689-97   As specified on drawing. Thickness guide (not part of spec.)
Type I   Nickel electroplated from solutions nof containing hardeners, brighteners, or stress control additives.
Type II   Nickel electrodeposits used at moderate temperatures and containing sulfur or other codeposited elements or compounds that are present to increase the hardness, to refine the grain structure, or to control the intemal stress of the electrodeposited nickel.
Class 5 5µm (0.00020″)  
Class 25 25µm(0.0010″)  
Class 50 50µm(0.0020″)  
Class 100 100µm(0.0040″)  

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

 

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.


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.

SILVER

Silver coatings are generally used for weldable surfaces, electrical contact characteristics, high electrical and thermal conductivity, thermo-compression bonding, wear resistance of load-bearing surfaces, and spectral effectiveness. Silver is relatively noble and, as such, will form dip deposits on the surfaces of less noble metals that are immersed in its solution. This tends to happen even when the base metal enters the silver solution “hot” or “live”, that is, with a voltage already applied.


Benefits

  • Excellent thermal and electrical conductivity.
  • Hight ductility.
  • Hardness.
  • Temperature resistance.
Specs Thickness Comments
ASTM B 700-08 Unless otherwise specified 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. Electrodeposits without luster, obtained
from electroplating solutions operated without the use of
brighteners.
Grade D   Semi-bright. Semi-lustrous electrodeposits obtained
by the use of addition agents in the electroplating bath.
Class N   A finish that has had no supplementary tarnish resistant treatment.
Class S   A finish that has had a supplementary tarnish resistant treatment.
  1µm (0.00004″) Minimum for short-term shelf life solderability
  2.5µm (0.00010″) Min¡mum for contact connectors having limited wear
  5µm (0.00020″) Nominal thickness for lhermocompression bonding and nominal thickness for domestic hollowware
  10µm (0.00040″) Medium-quality hollowware, short-life domestic cutlery and flatware, and suggested th¡ckness for thermocompression bonding and die attachment for semiconductors
  20µm (0.00080″) Normal hotel flatware and high-quality domestic flatware and hollowware
  >40µm (0.0016″) Applications where very severe wear resistance is required,
such as machine bearings and for high-quality flatware

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.

Tumblast

The tumblast or rotary belt shot blasting process provides shot blasting for different size bulk parts. It is a simple process to operate and is used, among other applications, to remove lamellae from ferrous and non-ferrous castings, for forged parts; deburring of steel parts; cleaning of parts with heat treatment; cleaning and preparation of surfaces where subsequent coatings will be applied.

Blasting equipment is used, among other applications, for the following jobs:

  • Surface preparation for coating.
  • Pickling of forgings or heat-treated parts.
  • Deburring of metallic and non-metallic parts.
  • Oxide removal.

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.

surtec1

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

ZINC

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.

zinc1

zinc2

zinc3

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
Specs Thickness Comments
ASTM B 633-07 No dimensional change The primary use of chromate finishe on zinc is to retard or prevent formation of while corrosion products on zinc surfaces..
Fe /Zn25 SC4(very severe) 25µm(0.0010″)  
Fe/Zn 12 SC3 12µm(0.0050″)  
Fe/Zn8 SC2 8µm (0.00032″)  
Fe/Zn5 SCI 5µm (0.00020″)  
Type I   As plated without supplementary treatment.
Type II   With colored chromate treatment. 16h Salt Spray
Type III   With colorless chromate treatment. 96h Salt Spray
Type V   With colorless chromate treatment. 72h Salt Spray
Type VI   With colorless chromate treatment. 120h Salt Spray

Bright Dip

Bright Dip is a bright dip for brass and copper alloys that is used to protect and extend the life of the base material. Parts go through a cleaning process first to remove any oil and dirt that may be on them during processing and manufacturing. The parts are then processed with the acid-based chromate conversion coating. The film that forms from the bright immersion of copper and brass increases service life and prolongs future tarnishing and corrosion of the base material.

Benefits

  • Resistance to corrosion. 
  • Add shelf life..

Hidrogen release process

It is often referred to as hydrogen-induced delayed brittle failure, hydrogen stress cracking, or hydrogen embrittlement. Hydrogen can be introduced during cleaning, pickling, phosphating, electroplating, auto catalytic processes, porcelain enameling, and in the service environment as a result of cathodic protection reactions or corrosion reactions. Hydrogen can also be introduced during manufacturing, for example during profiling, machining and drilling, due to breakdown of unsuitable lubricants, as well as during welding or brazing operations.

When atomic hydrogen enters steel, it can cause loss of ductility, bearing capacity, or cracking. (usually as submicroscopic cracks), as well as catastrophic brittle failures in applied stresses. Below the yield strength or even the normal design strength for alloys.

Specs Thickness Comments
ASTMB850 No dimensional change The release of hydrogen consists of the application of heat at a certain temperature and time parameter of the material to prevent the piece from cracking.