Surface technology for theHigh Tech Industry

clean, cleaner, cleanest.

• Pharmacy• Aviation and aerospace• Vacuum application• Biotechnology• Semiconductor industry

• Grinding and polishing• Pickling and passivating• Electrolytical polishing• Ultrasonic cleaning• Packing & warehousing

IntroductionIn high tech industry there is a clear need for materials which give off gas

and/ or (dust) parts as less as possible to their environment. In the applications where the production process is sensitive for contamination,

such as the production of semiconductors which take place in a clean room. Due to corrosion stability and processing qualities stainless steel is a

material which is widely used as base material for parts. The chosen surface treatment influences these qualities strongly.

Grinding and polishing

Lowering the roughness. Usually lowering the roughness also reduces the chance of attachment of contamination. Grinding reduces the roughness and that is why this is very suitable for polishing. The roughness

which is achieved by grinding is modifying for the final roughness value

after polishing.

Pickling and passivatingWhen stainless steel is welded accelerated oxidation appears, both on the welding and the material. This oxidation is visible as a blue coloured zone

and causes a reduced corrosion stability. Also in the oxide skin several contaminations can be enclosed, which can be released at high-graded

(vacuum) application, possibly in molecular form. In the world of stainless steel degreasing and then pickling-passivating with hydrogen fluoride and nitric acid is a common known method to remove discolorations, oxides

and enclosed contaminations and to recover the corrosion stability. However, in high tech industry additional, extremely high demands are

placed on the purity of the surface. This is why electrolytical polishing of the parts is necessary.

Stainless steel in high grade (vacuum) applications

In clean room surroundings contaminations such as finger prints, dry spots and carbon brands in the weld can cause disruptions. Even exposing the stainless steel to corroding media at certain temperatures can lead to cracks in the material at which parts can be released, the so-called “metal dusting”. Here the contamination is made by the material itself. Even as the material was delivered almost contamination free. During the pickling process of stainless steel atomic hydrogen absorbing in the stainless steel occurs. However, this can cause an extra degree of gassing out at vacuum applications. Although hydrogen is often seen as an innocent contaminant, in industry there are sufficient examples which indicate that this leads to part forming, the (partial) coming off of coatings and even to undesired chemical reactions on the surface.

- continuance

Stainless steel in high grade (vacuum) applications

- After all this atomic hydrogen is chemically reactive and increases the chance to contamination. An additional warmth treatment can put this right. Herewith the stainless steel must be delivered completely clear, because otherwise, contaminations caused by warmth treatment can be fixated on the surface. The gassing out of the cleaned part is used as measure method in a vacuum surrounding. After chemical cleaning the gassing out can increase to 6*10 -13 torr·l/cm² s. With the right warmth treatment this gassing out can be lowered with about factor 600.

Electrolytical polishing The method to make stainless steel suitable for high graded applications

has the following features:• First of all by reducing the roughness the attachment of gasses

(adsorptions) is strongly reduced which is positive for vacuum applications. The pump times can be reduced with factor 10 at a much better and more stable vacuum quality.

Electrolytical polishing• Secondly electrolytical polishing is an anodic process, that suppresses the

transfer of atomic hydrogen strongly.• Thirdly during electrolytical polishing an enrichment of high graded

elements at the surface such as chromium and nickel occurs.

before electrolytical polishing after electrolytical polishing

General guidelines

Important to every chemical treatment of stainless steel is that the material is treated with contamination free pickling, polishing and flushing fluids. In high tech industry the smallest organic contamination can have reaching results.

FacilitiesDerustit surface technology

• Computer controlled polishing street, operating system grafted on “Copy Exact”

• Ultrasonic cleaning installation• Conditioned pickling hall 1200m²• Heated demin water bath• Demin water by “reversed osmoses” accommodated with UV-unit• Air network accommodated with absolute filter

FacilitysDerustit surface technology

• Dust-free packing room accommodated with the necessary disposables and UV-lamp

• Conditioned grinding and polishing department• Laboratory for among others bath analysis• Fully integrated care system (copy exact)• Warehousing, conditioned storage and transhipment space 800m²

Semicon procedure

“Derustit surface technology has been developing from supply pickling agency to specialist in surface technology for the past two decades. The described processes are fully integrated in

the daily business. Herewith she distinguishes from her competitors, and she guarantees the advocated quality of her

customers and end users”.