SURFACE TREATMENT (METAL) - New Material...
Transcript of SURFACE TREATMENT (METAL) - New Material...
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SURFACE TREATMENT (METAL)
INTRODUCTION
• Physical/Chemical process or treatment used on the layer surface of materials for enhancement of
Appearance: Color, Pattern, Logo, Shininess etc.
Texture: Roughness, Quality etc.
Feature: Hardening, Anti-Fingerprint, Anti-Scratch
Types of treatment
Anodizing
Coating – PVD, Powder
Plating – Electroplating
Etching MICRO-ARC OXIDATION
Micro-arc Oxidation
ANODIZING
• Use of electrochemical principle • Generate a layer of Al2O3 (alumina) film on the surface of aluminum
and its alloys. • Usually refers to sulfuric acid anodizing oxidation.
INTRODUCTION
PURPOSE
• To form a layer of aluminum oxide and protect the aluminium layer for,
Improved resistance towards wear and corrosion. Enhance the appearance and hardness. Promote paint adhesion. Increased and enhance capacitance in electronic appliances.
ANODIZING
Pre-treatment Anodizing Post-treatment
Pre-treatment
• To improve the surface of metal before anodization takes place
• Include: • Degreasing: To remove any fabrication oils or buffing
compounds • Polishing: To produce smooth math gloss aluminium
surface • Washing: To clean the surface from any heavy metal
hydroxide
Anodizing
• To form anodic oxide layer on the surface of aluminium • Continuous process and stop when desired thickness of layer is
achieved • Include:
• Electrolyte bath, usually sulfuric acid • Anode: Metals to be treated • Cathode: Aluminium or lead
ANODIZING
• Coloring • Integral color: Impart the color during anodizing bath take
place and provide more resistance on abrasion • Electrochemical color: The color is imparted after it is formed
where the coatings is porous and capable of absorbing the color
• Sealing • To seal the pores of the oxide layer • To increase the resistance towards corrosion • To reduce wettability • Ways of sealing: Hydrothermal, Cold impregnation or both
ANODIZING
APPLICATION
Automotive Industry
Medical Equipment
Marine Industry
Aviation & Aerospace
Electronics
Home furnishing
Pros Cons
Durable over time Limited color selection
Easy to maintain
Easy fabrication
Color sustainability
PROS & CONS
ANODIZING
• Processes in which a material is converted to its vapor phase in a vacuum chamber and condensed onto substrate surface as a very thin film.
• Used to produce or deposit thin film technology that carried out under high vacuum and at temperature of 150°C to 500°C.
• Type of PVD coating: • Evaporative deposition • Electron beam vaporization • Pulse laser deposition • Sputter deposition
PVD COATING
INTRODUCTION
Evaporation Transportation Reaction Deposition
PURPOSE
• To improved hardness and wear resistance • To reduced friction • To enhance the oxidation resistance
PROCESS
• Evaporation : Target consisting materials to be deposited is
bombarded with high energy source of ions/electrons beam. Causing dislodge of atoms from the surface of the target and the target vaporized.
• Transport: Movement of vaporized atoms to the substrate for coatings.
• Reaction: Target will react with the gas during transportation process.
• Deposition: Process of build up the coatings on the surface of substrate.
PVD COATING
PVD COATING
Electron beam deposition system
Pulse laser deposition system
Sputter deposition system
PROS & CONS
Pros Cons
• Can be used for almost any type of inorganic and organic materials
• High capital cost
• Environmental friendly process • Rate of coating deposition is slow
• Top coats are not necessary required
• Need cooling system as process require large amount of heats • Good strength and durability
APPLICATION
Aerospace Automotive
Surgical/Medical Dies and molds for materials processing
Cutting tools Fire arms
PVD COATING
POWDER COATING
• Use electrostatic Spray Machine to coat the powder to the surface of metals. The electrostatic powder is evenly adsorbed on the surface to form powder coating.
• High temperature coatings leads to the coatings to solidified as different types of powder coatings is used.
Pre-Treatment
Powder Coating
Oven Curing
Packaging
INTRODUCTION
PROCESS
Pre-treatment: Process to prepare the aluminum for coatings. Successful adhesion of powder to the aluminum is dependent upon the quality of pre-treatment.
Powder coating: Consist thermoset resins, pigment & additives where it is applied to the metal surface using powder coating gun or electrostatic spray gun.
Oven curing: Painted products are cured using oven baking. The powder liquefies and the resin cross link producing tough and durable surface finish.
Packaging: Prevent marking of finished surface of metals.
Pros Cons
• Rich in color • The usage in electronic products is low • Low cost which suitable for
furniture
• High utilization rate and have shielding defect ability
PROS & CONS
APPLICATION
Architectural Automotive Household equipment
POWDER COATING
POWDER COATING
Powder coating unit with electrostatic spray
guns
Drying/curing oven
ELECTROPLATING
• It is involve the passing of electric current through electrolyte solution, electrodes and power supply.
• It is also known as electro deposition process where it is involves deposition of thin later of metal onto the work piece surfaces (substrate).
INTRODUCTION
PURPOSE
• To increase the thickness of metal surface.
• To enhance the wear resistance properties.
• To improve the electrical conductivity of metals
Pre-Treatment Electroplating Finishing
PROCESS
Pre-treatment • Cleaning: Include the stripping process where removal of plating or
paint is done. It is done by dipping the electrode into strong acid or alkaline briefly to remove all the impurities.
Electroplating • Need metal that can conduct electricity. • Anode is plating metal while cathode is the target to be treated. • Both electrode is immersed in the solution which containing the ions
and when power is switch on, the ions from anode will be dissolve in the solution and deposited onto the cathode electrode.
• This will formed a thin layer of metal plate at the cathode.
Finishing
• Chemical rinsing: To make the metals more resistance towards corrosion.
• Water rinsing: Using hot water to remove any chemical residue
ELECTROPLATING
Electroplating Module
PROCESS
Pros Cons
• Produce high quality metallic and glossy appearance
• Not environmental friendly process
• Substrate of SUS, Al, Zn and Mg is relatively low cost
• Cost and time consuming process
• Improved physical properties of metals and extend the metal life
• Plating is not uniform
PROS & CONS
APPLICATION
Jewelry Car Parts Kitchen
Equipment
• Refers to the exposure of the plate after removing the protective film etching region, which in contact with a chemical etching solution to dissolve corrosion
• Resulting on the formation of irregularities or hollow molding effect.
• Divided into two types,
Dry etching: Materials is dissolved when immersed in chemical solution
Wet etching: Materials is sputtered or dissolved using reactive ions or vapor phase etchant
ETCHING
INTRODUCTION
PURPOSE
• To remove material from areas identified by the lithography process Areas of photoresist exposed to light Developing leaves only these areas open Etching removes substrate areas not masked
• To create structures for functional use
• To remove oxide layers below features to allow for motion
PROCESS
Metal store
Cleaning Coating Photo-mech
Developing
Etching Dimensional inspection
Stripping Inspection Packaging
Metal store • Sheet metal from a comprehensive metal store is cut to size
Cleaning • The cut sheet are cleaned to ensure they are chemically clean
Photo-mech • The coated metal plates are placed between multi-image photo-tools and exposed to UV light
Developing • The unwanted photo-resist is developed away leaving the component shape is protected
Etching • Etchant removes unprotected metal under precise control
Dimensional inspection • Etched parts are dimensionally checked against drawing data
Stripping • Photo-resist is removed from the etched component
Inspection • Parts are viewed and inspected
Packaging • Components are packed & dispatched
EQUIPMENT
Dry etching machine
Vacuum plasma etching machine
Pros Cons
• Give natural appearance with high gloss
• Corrosive acid or alkaline liquids is used
• Produce a relatively durable finish • Most of liquids used is hazardous
• Only done periodically • Thus, not environmental friendly process
Manufacturing of printed circuit boards
Manufacture of semiconductor
devices
Used in preparation of metallic specimen
for microscopic observation
APPLICATION
PROS & CONS
MICRO-ARC OXIDATION (MAO)
• Process of generating a high voltage ceramic surface coating is applied in an weak alkaline electrolyte solution where a physical discharge process and electrochemical oxidation occurs.
• Through the electrolytic solution, the electrochemical formation of the anodic film on the surface of metal is existing by spark or arc discharges.
• Resulting in the initiation at potential above the breakdown voltage of growing oxide film.
• The arc and plasma discharges move rapidly across the anode surface.
• As a result, a coating layer, consisting of oxidized forms of the elements of the base metal and electrolyte components, is formed.
INTRODUCTION
PURPOSE
• Forming a porous ceramic coatings of complex
composition. • To enhance wear-resistance. • To improve the corrosion and heat resistance • To produce metals with low dielectric capacity, • Enhancing the light-reflecting and light-absorbing features of
metals.
PROCESS
Pre-treatment
MAO Drying
Process
• The metal need to be treated in the pre-treatment process where all the impurities is removed on the metal surface.
• The metal used as an anode is immersed in environmental friendly alkaline electrolyte.
• Initiation of discharge is provided when the micro arching voltage at which the dielectric breakdown of the oxide film occurred.
• The electrolyte is pumped through a filter and heat exchanger and then introduced into the process chamber with micro bubbles oxygenating the electrolyte.
• The oxide film proceeds as substrate metal oxidation. • Electrolyte additives is such as phosphates and silicate is introduced
into the coatings. • The high voltage supplied to the anode causing the oxide later to
be formed and when critical voltage degree is exceeded, micro arc oxidation process start to occur.
• The oxide layer formed is cooled, dried and finishing process where coloring or sintering take places.
EQUIPMENT
Micro-arc oxidation unit
SEM image for MOA
PROS & CONS
Pros Cons
• Ceramic texture, appearance dull, no high-light products, delicate touch, fingerprint-proof
• Currently restricted color, only black and grey.
• Can used variety of base materials such as Al, Ti, Zn, Zr, Mg, Nb and their alloys.
• Bright color is difficult to achieve
• Simple pretreatment product corrosion resistance
• High cost in power
• Excellent weather resistance
• Excellent thermal performance.
Thermal
• Low thermal conductivity of metals can increase the thermal shock resistance
Electric & Electronics
• Used as insulator film
• Hard coatings for inner areas
Chemical
• Resistance to strong acids and bases.
• Used in chemical and food industries
Mechanical
• Used in lubrication process
• Higher hardness can increase sliding, abrasive and erosive wear resistance
APPLICATION
• This slide presentation is prepared by Research & Development Team, KGC Resources Sdn Bhd
• Any inquiries, feel free to email us at [email protected]
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