Product Introduction

Polishing technology
Polishing treatment and Matte finish
Nippon Hyomen Kagaku Kabushiki Kaisha R & D center

Introduction

Degreasing → Chemical polishing → (anti-discoloration)

Various metal members such as iron, aluminum, and→ Drying

copper are utilized in many fields such as automotiveindustry, building field, and medical field. These metal

In the electrolytic polishing of stainless steel, themembers in many cases, in order to improve the appearance

treatment is performed in the following steps.

andDegreasing → Neutralization → Electrolytic polishing →functionality(slidability,

deburring,corrosionresistance), it is common that some surface treatment is(pickling) → Neutralization → Drying

performed.
We have sold surface treatment agents such as chemical

In the alkali chemical matte finish treatment of aluminum,

polishing, electrolytic polishing, and matte finish forthe treatment is performed in the following steps.

metallic materials for many years. This paper presents these

Degreasing → Chemical matte finish → Desmatting →technologies.

Drying*In the above three treatments, water washing is performed

Product Summary

between each step.

Surface treatments such as chemical polishing,electrolytic polishing, and matte finish have the following
features.
Features・ Appearance is improved by glossiness improvement orroughening.
・ It is also possible to polish the recessed part or the backMechanisms
In chemical polishing and electrolytic polishing, thetarget metal is immersed in the treatment solution, it ispossible to obtain a smooth surface by preferentiallydissolving the convex portion. (Figure 1) However, just byimmersing it in a chemical, both the convex portion and theside of the workpiece because it is treated with aconcave portion are uniformly dissolved. Therefore, thechemical solution.

dissolution rate is adjusted with a treatment agent.

・ In the electrolytic polishing of stainless steel, thepolishing solution

chromium ratio of the material surface increases by thetreatment, and the corrosion resistance is improved.
・ In chemical polishing, deburring of fine precision parts
can also be carried out stably.

metalpolishing solution
thin layer(fast dissolution)
polishing solution(high metal conc.)
thick layer(slow dissolution)metalpolishing solution
polishing solution(high metal conc.)

metal・ It has a number of years of achievements.
Figure 1: Dissolving Mechanism of Chemical Polishing andTreatment process

Electrolytic Polishing

Since the treatment process varies depending on thematerial and the treatment content, some examples are
introduced in this paper.
For example, in the chemical polishing treatment ofcopper, the treatment is performed in the following step.

In chemical polishing, a reaction inhibitor is added to an
acidic liquid, and a dissolution rate is changed by aconcentration gradient of a metal ions to smooth the surface.
In the concave portion, the metal dissolution reaction is202010301 JASCO Nippon Hyomen Kagaku Kabushiki Kaisha 1

[Product Introduction] Polishing Technology

suppressed because the concentration of metal ionsand the dissolution reaction proceeds. (Figure 2) Use thisdissolved from the material increases. In the convex portion,

phenomenon to make materials rougher.

the metal dissolution reaction proceeds because the metalions dissolved from the material are easily diffused. Due tooxide film

this difference in dissolution rate, the convex portion ispreferentially dissolved and smoothed.
Electrolytic polishing has a similar mechanism, but theelectrolytic polishing solution is a slightly viscous liquid that
controls the diffusion of metal ions. In the concave portion,

metalmetalmetalThe
presenceofchloride ions (Cl-)
locally destroys theoxide film.

Corrosion progresses
locally.

As Cl- moves toward
the inside of thepitting,theClconcentration
increases and thepitting progresses.

the metal ion dissolved from the material is difficult todiffuse and the metal dissolution reaction is suppressed, andFigure 2: Dissolving Mechanism of Matte Finish

in the convex portion, the metal ion dissolved from thematerial easily diffuses, so that the metal dissolution

In closing

reaction proceeds. Due to this difference in dissolution rate,

There are various types of chemical polishing agents,

the convex portion is preferentially dissolved and smoothed.

electrolytic polishing agents, and chemical matte finish

Further, in electrolytic polishing, the convex portion near theagents depending on the material and purpose. (Table 1) If

counter electrode has a high current density, so that it is easy

not only existing materials but also new materials areto dissolve.

developed, it is also possible to custom-make theIn chemical matte finish, the surface is roughened by thecorresponding polishing and matte finish agents.

use of pitting corrosion. The chlorine-containing treatment
agent locally destroys the oxide film on the metal surface,

Table 1: Lineup of Polishing and Matte Finish Agents
Product namePurposes

Type

6C016

Electrolytic polishing agent for stainless steel

Acid

K-584

Chemical polishing agent for stainless steel

Acid

ES-581

Matte finish agent for stainless steel

Acid

6C019

Chemical polishing agent for steel

Acid

6F233S

Chemical polishing agent for copper

Acid

6G064

Matte finish agent for copper

Acid

Chemilite 53

Chemical polishing agent for aluminum

Acid

Aluetch 83

Matte finish agent for aluminum

Acid

6L132

Matte finish agent for aluminum

Alkaline

K-381

Chemical polishing agent for zinc die casting

Acid

Titanic 99

Chemical polishing agent for titanium

Acid

202010301 JASCO Nippon Hyomen Kagaku Kabushiki Kaisha 2