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Business Introduction

Surface treatment

"CROMAX" is an in-house developed coating that has advanced hard chrome plating.
Dense structure, three directional crystal-oriented coating, the durability is superior to conventional chromium plating.
Please try it!

CROMAX

CROMAX is our next-generation coating which has a long lifetime and high durability.
Compared to conventional hard chrome, it is 20% harder, and wear resistance is increased 2 to 3 times.
Furthermore, because of the low temperature treatment of 49 ±1°C, it is super hard and there is no worry of distortion.
The crystal structure of CROMAX is very fine, it grows in three directions and becomes more complex and stronger than conventional unidirectional chromium film. It can cope with loads from many directions.

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Usage When more wear resistance is required than conventional hard chromium plating.
High Hardness / Wear Resistance / Seizure Resistance
Products
  • Rubber mold
  • Plastic mold
  • Press mold (stamping Die)
  • Glass mold
  • SMC mold
  • Sand mold
  • Tile mold
  • Slate mold
  • Roll
  • Machine parts
  • Jigs and Tools etc.
Maximum Processing Size 5500 × 3000 × 1500
Maximum Weight 20t
Material
  • Iron
  • Cast iron
  • Copper
  • Stainless steel
  • Aluminum
  • Other non-ferrous metal (Please consult with us)
Baking
  • 191°C
  • 3~5h
Inspection
  • Appearance
  • Coating thickness
  • Tolerance dimension
  • Grade certificates are available.
Characteristics comparison of hard chromium and CROMAX.

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Hard chromium Comparison CROMAX
Hv900 Hardness Hv1,200
35DS/mg Wear resistance (type SUGA) ※1 160DS/mg
1328.5µm² Wear resistance (type Ball On Disc) ※2 85.2µm²
Ra 11.5nm Surface Roughness Ra 8.6nm
1 Orientation Coating structure 3 Orientation
White ~ Glossy Appearance Super Glossy
  • ※1 Type SUGA
    To shave1mg off will required number of rotations (DS/mg) of the grinding wheel.
    The larger the value, the better the wear resistance.
  • ※2 Type Ball On Disc
    The mating material be Carbide, load 3.0 (N), speed 10.0 (cm / s) (µm²)will be the wear area.
    The smaller value gives better wear resistance.
Hard Chrome Plating

Hard Chrome Plating has specular gloss, is highly corrosion resistant, and is strong against discoloration.
Also, it has industrial surface treatment characteristics such as excellent hardness and wear resistance, low friction coefficient and excellent releasability and corrosion resistance.

Jig tool parts and machinery parts (see the 3 photos at the bottom right side) wear resistance ・lubrication ・overheat prevention

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Usage
  • Wear resistance
  • High hardness
  • Mold-releasability
  • Lubrication
  • Corrosion resistance
  • Overheat prevention
Products
  • Rubber mold
  • Plastic mold
  • Press mold (Stamping Die)
  • Glass mold
  • SMC mold
  • Sand mold
  • Tile mold
  • Slate mold
  • Roll
  • Machine parts
  • Jig tools, etc.
Maximum Processing Size 5800 × 3300 × 2000
Maximum Weight 20t
Material
  • Iron
  • Cast iron
  • Copper
  • Stainless steel
  • Aluminum
  • Other non-ferrous metal (Please consult with us)
Small Hole / Blind Hole Please consult with us
Hydrogen Removal(Baking) Correspondence at 191°C, 3 to 5 h
Inspection
  • Appearance
  • Coating thickness
  • Tolerance dimension
  • Grade certificates are available.

Press mold (stamping Die)
Mold-Releasable・焼付け防止・Abrasion resistance

(1) Rubber mold
(2) Plastic injection molding
Mold-Releasable・Corrosion resistance
Coating properties of hard chromium plating
High hardness

Hard chrome plating has the highest hardness in ordinary electroplating, and it is much harder than heat treated steel, nitride steel, etc. (Hv 800 to 1,000)

Heart-Resistant

The change in hardness due to heat treatment gradually decreases from 200 to 400°C and rapidly decreases at 400°C or higher. When the temperature reaches 800°C or more, it reaches the normal chromium metal value HV 200~300. This is due to the fact that the crystal of electrodeposited chromium collapses and recrystallizes near 500°C. Heat treatment for recovering hydrogen embrittlement of plating is carried out at around 200°C and is not affected by the structure of electrodeposited chrome.

Low coefficient of friction

The coefficient of friction of chromium plating is extremely small; the smallest among commonly used materials.

Friction coefficient of steel and chromium plating

Combined material Resting Motion
Steel and Chrome plating 0.17 0.16
Steel and Steel 0.45 4
Abrasion resistance

The most important basic property of hard chrome plating is excellent abrasion resistance.

Comparison of wear amount of various plating (mating material: grindstone)

Types of plating Average wear rate (very 2 hours (0.1mg))
Hard Chrome 3
Nickel 12
Copper 17
Silver 20
Corrosion resistance

Hard chrome plating is stable against chemicals other than chlorides, even airborne chemicals, and coatings with a thickness of 10 µm or more have relatively good corrosion resistance.

Mold-Releasable

Chromium plating is generally considered to have good mold-releasability.
The reason is that the surface energy of each metal is smaller than other metals.
For example, regarding water repellency, when the water droplets drip on steel and chromium plating, the contact angle between steel and water droplets is 40° and between chromium plating and water droplets is 70°. Because of this, chromium plating releases easily and is not sticky.

Example of application field of hard chromium plating and usage

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Field Applicable Parts Purpose
Automobile
  • Crankshaft
  • Duel Shaft Journal
  • Cam
  • Cylinder Liner
  • Camshaft Journal
  • Various Shafts
  • Piston Ring
  • Piston Rod
  • Bearings, etc.
  • Wear Resistance
  • Lubrication
  • Porosity
  • Hardness, etc.
航空機
船舶
  • Crankshaft
  • Duel Shaft Journal
  • Cylinder
  • Valve
  • Piston Ring
  • Piston Rod
  • Pin
  • Slide Tube
  • Axis etc.
  • Wear resistance
  • Laser welding regeneration
  • Lubrication
  • Porosity etc.
Industrial Machinery
  • Textiles
  • Chemistry
  • Food
  • Pharmaceutical
  • Drying cylinder for printing and others
  • Various Cylinders
  • Various roles
  • Screen plate
  • Spindle
  • Mandrel
  • Sleeve
  • Piston rod
  • Hydraulic ram
  • Valve
  • Compressor crank etc.
  • Wear resistance
  • Corrosion resistance
  • Lubrication
  • Porosity
  • Hardness
  • Non-stickiness
  • Pollution prevention etc.
Inspection Tools
Cutting Tools
  • File
  • Fries
  • Plank gauge
  • Micrometer
  • Ring gauge
  • Various gauge
  • Reamer
  • Twist drill
  • Tap
  • Various drills
  • Non-stickiness
  • Wear resistance
  • Lubrication
  • Hardness
  • Laser welding regeneration
  • Machinability etc.
Mold
  • Glass mold
  • Plastic mold
  • Various molds
  • Wear resistance
  • Non-stickiness
  • Laser welding regeneration etc.
Chemical industry
  • Various tower tank
  • Pump shaft
  • Impeller
  • Valve etc.
  • Corrosion resistance
  • Wear resistance etc.
Electroless Nickel Plating

Electroless Nickel Plating is called chemical plating and the method of plating metal by chemical reduction without using a power supply.
Electroless Nickel Plating is widely used in industry and mainly used for objects needing wear and corosion resistance.
Machine parts, shaft (See below) Corrosion resistance ・Accurate dimension ・Wear resistance

It's possible to apply plating on various metal materials, plastic, ceramics, etc. Even against complicated shapes it can be plated with uniform coating thickness.
In addition, the mechanical properties, electrical characteristics, and physical properties are highly regarded in many industrial fields.

Rubber mold
Support corrosion resistance ・Abrasion resistance・Complicated shapes

Characteristics of coating by Electroless nickel plating
Chemical Organization Ni:90~92% P:8~10%
Organization It is nearly amorphous in the precipitated state, it turns into a crystalline form upon heat treatment and shows a precipitation hardening appearance.
Electric Resistance 60 µΩ / cm / cm², those heated at 400 °C or more drop to 1/3 or less.
Thermal Conductivity 0.0105~0.0135cal/cm・sec・°C
Magnetism Almost nonmagnetic in the precipitation state. Magnetism is generated by heat treatment at 300°C or higher.
Abrasion Resistance Electroless nickel plating is superior to Electro Nickel Plating. Those heat-treated at 650°C are sometimes superior to hard chromium plating depending on how the material is treated.
Uniformity Perfect bond regardless of shape.
Possible to uniformly deposit the coating.
Accuracy within ±10%
Corrosion Resistance It is superior to pure nickel, is not compromised by most organic solvent at all, it shows good corrosion resistance to organic acids, salts, caustic alkali and dilute mineral acid.
Hardness Precipitation state: HV 500 to 550. 400°C
Heat treatment: HV 800~1000

Application examples of electroless nickel plating and usage

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Field Application parts Purpose
Automotive industry
  • Disk brakes
  • Piston
  • Cylinder
  • Bearings
  • Precision gears
  • Axis of rotation
  • Valves
  • Inside the engine etc.
  • Hardness
  • Wear resistance
  • Overheat prevention
  • Corrosion resistance
  • Accuracy etc.
Electronics industry
  • Contact
  • Shaft
  • Spring
  • Bolt
  • Magnet
  • Resistor
  • Computer components
  • Electronic parts etc.
  • Hardness
  • Accuracy
  • Corrosion resistance
  • Solderability
  • Weldability etc.
Precision mechanical equipment
  • Copying machine
  • Optical equipment
  • Various parts such as watches
  • Accuracy
  • Hardness
  • Corrosion resistance etc.
Chemical industry
  • Various Valves
  • Pump
  • Swing valve
  • Reactor
  • Heat exchanger
  • Corrosion resistance
  • Pollution prevention
  • Antioxidant
Galvanizing / Black Dyed

Gloss chromate (trivalent), chromatic chromate, black chromate

Used in a wide range of fields as an effective iron rust prevention plating method. It has been extremely effective for corrosion protection of iron and the quality of appearance has been improved by the progress of plating baths and chromate treatment.
It has been highly evaluated for decorative applications.
In our company, in response to environmental issues, we converted the glossy chromate to trivalent chromium meters.

Machine parts / tool parts / other rust preventive products

  1. Gross chromate (trivalent)
  2. Yellow chromate
  3. Black chromate

Identification by corrosion resistance and color, etc.

Black Dyed (black oxidation treatment with alkali bath)

It is a kind of chemical conversion treatment used foe steel products. imparting a black appearance by immersing iron products in concentrated NaOH solution. It is mainly used for black appearance and corrosion prevention.
The principle is that iron ferric oxide dissolves in concentrated NaOH to form sodium ferrate. This is partly reduced by the co-produced hydrogen gas to become ferrous iron, which produces a ferric mixed iron oxide (Fe3O4) and colors everything black.
Corrosion resistance (rust prevention oil required) • Identification by color etc.

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Usage Rust prevention
Products Machine parts・Jig tool parts・Shaft etc.
Maximum processing size 1000 × 1000 × 1600
Maximum Weight 1t
Material
  • Iron
  • Cast iron
Baking 191°C 1~5h
Inspection
  • Appearance
  • Coating thickness
  • Tolerance dimension
  • It is possible to issue a certificate of grades.
Characteristics of zinc plating
  • It can evenly apply a plating to complicated shaped materials with uniform thickness.
  • In a neutral environment there is a passive region, and corrosion resistance is good. Corrosion in the region of pH 8 to 12 is particularly small, and the corrosion rate in the atmosphere is extremely slow at about 1/100 of iron.
  • The sacrificial corrosion protection against iron is strong and even if the plating surface is scratched and part of the iron surface is exposed, there is rust proofing
  • Because the chromate film as post processing prevents white rusting of zinc for a long time, its synergistic effect with 1 to 3 makes its rust prevention effect far superior to other rust prevention treatments
  • It is excellent in secondary processing after plating.
Zinc Plating Process

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Overview of various chromate treatments
Types of Postprocessing
(Zinc film thickness about 8µm)
Color tone of appearance Terms of use / Purpose Time for red rust to appear
Glossy Chromate Blue ~ Blue silver white Looks nice, but weak corrosion resistance. Around 240 hours
Color Chromate Golden or Rainbow Parts that emphasize corrosion resistance Around 800 hours
Black Chromate Black Parts that emphasize corrosion and excellent weather resistance Around 1000 hours
Green Chromate Olive Parts that are used in harsh corrosive environments Around 1500 hours
Nickel alloy / Composite Plating

Ni-P-PTFE (Nickel-Teflon), Ni-B (Nickel-Boron)
Ni-P-W (Nickel-Phosphor-Tungsten), Ni-Sic (Nickel-Ceramic)

It is also compatible with various alloys • composite platings such as water repellency • releasing nickel-Teflon, sliding nickel-phosphorus-tungsten, heat resistant nickel-boron, wear-resistant nickel-ceramics


Various molds / machine parts / jig tool parts

  1. Ni-P-PTFE (Nickel-Teflon)
    …Releasability, lubricity, non-stickiness
  2. Ni-Sic (Nickel-Ceramic)
    …Wear resistance, non-slip
  3. Ni-B (Nickel-Boron)
    …heat resistance, Corrosion resistance
  4. Ni-P-W (Nickel-Phosphor-tungsten)
    …Lubricity, corrosion resistance

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Usage Lubricity, Non-stickiness, High hardness, Water repellency, Corrosion resistance
Products
  • Various molds
  • Machine parts
  • Jig Tool parts
Maximum Processing Size / Weight Please consult with us
Material
  • Iron
  • Cast iron
  • Copper
  • Stainless steel
  • Aluminum
  • Other non-ferrous metals (Please consult with us)
Baking 280~400°C 1h (Curing treatment)
Characteristics of various coatings

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Name Appearance color tone Ratio Classification
Nickel Teflon
(Ni-P-PTFE)
  • Excellent non-stickiness, improved releasability
  • Friction coefficient with improved lubricity
  • Low containing type
    (PTFE:10~15vol%)
  • Medium containing type
    (PTFE:20~25vol%)
  • High containing type
    (PTFE:30~35vol%)
Composite plating
Nickel Phosphorus Tungsten
(Ni-P-W)
  • Excellent lubricity and high hardness(Hv750)
  • Excellent abrasion resistance
Ni:86~89%、P:8~9%、W:3~5% Alloy plating
Nickel Boron
(Ni-B)
  • Excellent heat resistance and high hardness(Hv700)
  • Excellent solderability
Ni:99%、B:1% Alloy plating
Nickel Ceramic
(Ni-SiC)
  • Excellent abrasion resistance
  • The nickel based coating has the highest hardness(Hv800)
Sic : About 10vol% Composite plating
Application examples of various coatings and usage

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Coating Usage Applied parts
Nickel Teflon
(Ni-P-PTFE)
  • Parts requiring low friction and stable sliding
  • Products requiring releasability and water repellency
  • Motor
  • Pump
  • Bearings
  • Cylinder
  • Plastic / Rubber shaping mold etc.
Nickel Phosphorus Tungsten
(Ni-P-W)
  • Parts requiring slipperiness and hardness
  • Roll the printer
  • Camera
  • Bearings
  • Shooter
  • Gears others
Nickel Boron
(Ni-B)
  • Parts requiring heat resistance
  • Parts requiring solderability
  • Internal combustion engine parts
  • Hydraulic system
  • Drive parts
  • Substrate
  • Lead frame etc.
Nickel Ceramic
(Ni-SiC)
  • Parts requiring wear resistance and hardness
  • Hydraulic pump parts
  • Injection molding nozzle
  • Cylinder piston
  • Heat block etc.
Alumite

An Alumite is used for wear resistance and rust prevention of machine parts and jig tools Also, it is easy to color and can provide various colors.


Machine parts・Jig tool parts・Decoration Wear resistance・Corrosion resistance・Coloring
 

Usage Wear resistance・Rust prevention・Coloring
Products Machine parts・Jig and tools
Maximum Processing Size 3000 × 800 × 1500
Weight Please consult with us
Coating properties of Alumite
Adhesion Excellent adhesion with the substrate
Coating structure The coating is an aggregate of fine hexagonal columns with straight tubular holes (pores) at the center.
Coating thickness Generally 5 to 20µm, Hard Almite 30~100µm
Hardness Generally 200~250 Hv, Hard Almite 400~450Hv
Abrasion resistance Excellent abrasion resistance and wear amount is about 1/30 of aluminum material.
Coloring property Dyeing and coloring can be done freely by adsorbing and precipitating paints and metals in numerous pores on the surface.
Coating properties of Alumite
Alloy number Purpose of anodizing
(Expanded material) Corrosion protection Coloring Gloss Abrasion resistance
1050 A A A A
1070 A A A A
1080 A A A A
1110 A A A A
2011 C C D C
2014 C C D C
2017 C C D C
2024 C C D C
3003 A B C A
3004 A B C A
4043 B B D B
5005 A A B A
5052 A A B A
5056 A A C A
5058 A A C A
5N01 A A A A
6061 A A C A
6063 A A B A
6N01 A A C A
7075 B B C B
7N01 B B C B
Alloy number Purpose of anodizing
(Expanded material) Corrosion protection Coloring Gloss Abrasion resistance
AC1B C C D C
AC2A C D D C
AC3A B D D B
AC4B C D D C
AC4C B D D C
AC5A C C D C
AC7A A A B A
AC8A C D D C
AC9A C D D C
         
ADC1 C D D C
ADC3 B D D B
ADC5 A A B A
ADC6 A B B A
ADC10 C D D C
ADC12 C D D C

Anodically processable A: Excellent B: Good C: Passable D: Difficult

Various Plating

We provide various surface treatments such as gold / silver / copper / tin / black chrome according to customer's requests.


Electronic parts, electrical contacts, various parts, accessories

  1. Gold Plating…electrical conductivity, corrosion resistance, accessories
  2. Silver Plating…electrical conductivity, solderability, accessories
  3. Copper Plating…electrical conductivity, thermal conductivity, decorative base
  4. Tin Plating…corrosion resistance, solderability, accessories
  5. Black Chrome Plating…anti-reflective property, heat absorbing property, corrosion resistance

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Coating Coating Properties UUsage
Gold plating
  • Good corrosion resistance
  • Electrical resistance is the smallest after silver plating.
  • It has good thermal conductivity, so it can be used in high temperature area
  • It is used in the form of hard gold plating (hardness Hv about 180) containing 0.1~8% of nickel, silver, indium, or cobalt in the coating because many applications require hardness and wear resistance such as sliding contacts.
  • Electrical resistance
  • Low contact resistance
  • Corrosion resistance
  • Solderability
  • Wear resistance (in case of sliding contact)
  • Smoothness
  • High frequency characteristics
  • Light reflectivity
  • Decoration
Silver Plating
  • Electrical conductivity is the best in metals
  • Good thermal conductivity
  • Excellent slidability
  • It has weak points of oxidation, vulcanization and tendency to fade.
  • Electrical conductivity
  • Low contact resistance
  • Solderability
  • Lubricity
  • Seizure prevention
  • Overheat prevention
  • Light reflectivity
  • Smoothness
  • High frequency characteristics
  • Decoration
Copper Plating
  • Excellent electrical conductivity
  • Excellent thermal conductivity (94% of silver)
  • Excellent spreadability
  • Copper plating has excellent gloss finishing and leveling. It can fill fine irregularities on surface.
  • Since copper plating is not able to carburize, it is used as a carburizing coating for steel.
  • Through-hole plating (printed circuit board)
  • For decorative plating base
  • Industrial Thickening
  • Electroforming
  • Carburizing coating
  • Electrical conductivity
  • Thermal conductivity
Tin Plating
  • Insoluble in organic acids
  • Excellent solderability
  • Excellent flexibility and lubricity
  • Since it is not nitride, it is used as a nitridation preventive coating of steel.
  • Steel for canning
  • Eating utensils
  • Hot water heater
  • Electronic components
  • Semiconductor components
  • Various mechanical bearing parts
  • Sliding parts
  • Prevention of nitriding of steel
Black Chrome Plating
  • Excellent corrosion resistance
  • Excellent light absorption (wavelength range of 0.3~2.5µm)
  • Excellent heat absorption
  • Used for anti-reflection and decoration purposes
  • Solar system (Solar Cell)
  • Heatsink for electrical parts
  • Anticorrosion
  • Decoration
Plating treatment to non-metallic materials

Aluminum is used in many fields for its weight saving characteristics.
There are alumite treatment of anodized film and plating on aluminum as surface treatments.
Aluminum is covered with a strong oxide coating. Therefore, in order to perform chromium plating or electroless nickel plating on aluminum, plating is carried out after applying special pretreatment to ensure adhesion.

Advantages of chrome plating on aluminum

Aluminum has advantages of light weight, good processability and high strength. On the other hand, some aluminum alloys have low hardness and drawbacks concerning friction and wear.
By applying hard chromium it is possible to obtain characteristics that cannot be obtained with alumite film

  • High hardness can be obtained
  • Wear resistance effect is obtained
  • Improved slipperiness
  • Improvement of design and aesthetic appearance such as shiny surface, satin finish
  • Improve mold releasability

As you can see, it is possible to have characteristics of chromium film not on aluminum surface.
It is possible to have characteristics of chromium film not on aluminum surface.

Advantages of electroless nickel plating on aluminum

Aluminum is said to be an amphoteric metal, and corrosion resistance is inferior in an acidic or alkaline environment.
Improved aluminum by applying electroless nickel.

  • Chemical resistance can be obtained
  • The shape of the material is not limited, it is a film with excellent plating adhesion and uniformity
  • Improved heat resistance
  • Conductivity added

It is possible to have characteristics of electroless nickel coating.

Processing steps

Processing of chromium and electroless nickel plating on the top of aluminum

By performing this zincate treatment in pretreatment, a plating film with good adhesion can be obtained on aluminum.

Major use products
  • Aluminum die-cast parts
  • Weak electricity
  • Heavy electricity
  • Lighting
  • Optical equipment
  • Electronic components
  • Building materials
  • Print roll
  • Medical equipment
  • Mobile phone parts etc.

Surface treatment to ZAS (zinc alloy) and copper alloy is also possible.

Chunichi Craft Co., Ltd.