This document discusses surface treatment technologies for stainless steel parts used in high-tech industries. It focuses on electrolytic polishing, which improves surface cleanliness and reduces outgassing in vacuum applications. Electrolytic polishing reduces surface roughness, suppresses hydrogen absorption, and enriches the surface with elements like chromium and nickel. It can lower the outgassing rate by a factor of 600 compared to chemical cleaning alone. The document also outlines other surface treatments like grinding, pickling, and passivating used to clean stainless steel and restore corrosion resistance. It emphasizes that contamination-free fluids and facilities are essential for high-purity surfaces in high-tech applications.

1. Surfacetechnologyfor theHigh Tech Industry

2. clean,cleaner,cleanest. Pharmacy Aviation and aerospace Vacuumapplication Biotechnology Semiconductor industry

3. Grinding and polishing Pickling and passivating Electrolyticalpolishing Ultrasoniccleaning Packing & warehousing

4. Introduction In high techindustrythere is a clearneedformaterialswhichgiveoff gas and/ or (dust) parts as less as possible to their environment. In the applicationswhere the productionprocess is sensitive forcontamination, such as the production of semiconductors whichtake place in a clean room. Due to corrosionstability and processing qualitiesstainless steel is a materialwhich is widelyused as base materialforparts. The chosen surface treatment influences these qualitiesstrongly.

5. Grinding and polishing Lowering the roughness. Usuallylowering the roughnessalsoreduces the chance of attachment of contamination. Grindingreduces the roughness and that is whythis is verysuitableforpolishing. The roughnesswhich is achievedbygrinding is modifyingfor the finalroughnessvalueafterpolishing.

6. Pickling and passivating Whenstainless steel is weldedacceleratedoxidationappears, bothon the welding and the material. Thisoxidation is visible as a blue coloured zone and causes a reducedcorrosionstability. Also in the oxide skin severalcontaminationscanbeenclosed, whichcanbereleased at high-graded (vacuum) application, possibly in molecularform. In the world of stainless steel degreasing and thenpickling-passivatingwithhydrogen fluoride and nitric acid is a commonknownmethod to removediscolorations, oxides and enclosedcontaminations and to recover the corrosionstability. However, in high techindustryadditional, extremely high demands are placedon the purity of the surface. This is whyelectrolyticalpolishing of the parts is necessary.

7. Stainless steel in high grade (vacuum) applications In clean room surroundingscontaminationssuch as finger prints, dry spots and carbon brands in the weldcancausedisruptions. Even exposing the stainless steel to corroding media at certaintemperaturescanlead to cracks in the material at whichpartscanbereleased, the so-called “metal dusting”. Here the contamination is made by the materialitself. Even as the material was deliveredalmostcontamination free. During the picklingprocess of stainless steel atomichydrogenabsorbing in the stainless steel occurs. However, thiscancausean extra degree of gassing out at vacuumapplications. Althoughhydrogen is oftenseen as an innocent contaminant, in industrythere are sufficientexampleswhichindicatethatthisleads to part forming, the (partial) coming off of coatings and even to undesiredchemicalreactionson the surface. - continuance

8. 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.

9. Electrolyticalpolishing The method to makestainless steel suitablefor high gradedapplications has the following features: First of all byreducing the roughness the attachment of gasses (adsorptions) is stronglyreducedwhich is positiveforvacuumapplications. The pump timescanbereducedwith factor 10 at a muchbetter and more stablevacuumquality.

10. Electrolyticalpolishing Secondlyelectrolyticalpolishing is ananodicprocess, thatsuppresses the transfer of atomichydrogenstrongly. Thirdly during electrolyticalpolishinganenrichment of high gradedelements at the surface such as chromium and nickeloccurs. beforeelectrolyticalpolishingafterelectrolyticalpolishing

11. General guidelines Important to everychemical treatment of stainless steel is that the material is treatedwithcontamination free pickling, polishing and flushing fluids. In high techindustry the smallestorganiccontaminationcan have reachingresults.

12. FacilitiesDerustit surface technology Computer controlledpolishingstreet, operating system graftedon “Copy Exact” Ultrasoniccleaninginstallation Conditionedpickling hall 1200m² Heateddemin water bath Demin water by“reversed osmoses” accommodated with UV-unit Air network accommodated with absolute filter

13. FacilitysDerustit surfacetechnology 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

14. Semicon procedure

15. “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”.