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Surface Treatment Infrastructure at CERN

This outline provides information on the infrastructure dedicated to surface treatment at CERN, including cleaning, electrolytic deposition, and preparation of various materials for UHV applications. Topics covered include stainless steel preparation, silver and gold plating, electrolytic deposition processes, and degreasing techniques.

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Surface Treatment Infrastructure at CERN

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  1. Groupe TE/VSC/SCC SURFACE TREATMENTS AT CERN FLORENT FESQUET PIERRE MAURIN TE-VSC

  2. Outline 1. Infrastructure dedicated to surface treatment 2. Cleaning and degreasing of parts for UHV applications 3. The electrolytic deposition at CERN • Whydoing a deposition? • Preparation of stainlesssteelprior to electroplating • Silverplating on aluminumalloys 4. Improvement and development TE-VSC

  3. Infrastructure dedicated to surface treatment TE-VSC

  4. Building 867 (Site Prevessin) Surface cleaning of large parts intended for UHV applications Preparation copper OFE Preparation Stainless steel Tube Max IV Infrastructure dedicated to surface treatment Tank DTL Linac 4 Preparation aluminum alloy Chambre VJ ATLAS TE-VSC

  5. Building 118 (Site Meyrin) Surface preparation: chemical polishing and electropolishing of copper and Nobium Chemical polishing of copper and niombium Superconducting cavity 5 cells Niobium for SPL (700 MHz) Superconducting cavity CRAB Copper test cavity (1300 MHz) Infrastructure dedicated to surface treatment Electropolishing of Niobium and copper Cavity HIE- ISOLDE TE-VSC

  6. Building 102 (Site Meyrin) Surface preparation of large parts intended for UHV applications Electropolishing stainless steel • Connectorstainlesssteel Disque of coppercavity PIMS • Guide-Onde LINAC4 • stainlesssteel Rhodium electroplating Ceramic • BGV Aluminumchamber Electrolytic deposition on stainless steel, copper and aluminum Silver electroplating Infrastructure dedicated to surface treatment Copper electroplating Gold electroplating • Tube de transition LHCVSR Doigts de contact écran TDI • Couvercle Tank LINAC 4 • Chambre LINAC TE-VSC

  7. Cleaning and degreasing of parts for UHV applications TE-VSC

  8. Degreasing aqueous phase Why cleaning a part ? GREASE MINERAL GREASE ANIMAL MATERIAL Bearing grease Handling Eliminate grease which pollute surface. Packaging Preparation of parts for UHV applications Eliminate the solid particles present in bold (i.e. particles machining, graphite residuals… Reduction of vacuum outgasing. Oil pump vacuum Cutting Oil Prepare the surface before vacuum deposition or electrolytic plating. TE-VSC

  9. Purpose of degreasing THE ALCALINE ELEMENTS Take off the grease stains and « trap » with surfactants Sodium silicate : Increase the wettability and etching inhibition. Phosphates : Sequestrant power and enhancement of the action of surfactants. THE SURFACTANTS (wetting) The surfactants lower the surface tension and capture of oil drops. Preparation of parts for UHV applications - - - + HYDROPHOBIC + + - - OIL + + - + + HYDROPHILIC + - - - Action of an anionic surfactant Stable emulsion TE-VSC

  10. Choice of degreasingprocessesbasedon materials Solvent Machine Halogenated / hydrocarbon mixture example of carbon chain : Porousmaterials Silicone valve Delicate parts Evaporation of the solvent Operating range: Preparation of parts for UHV applications • Loading • Precleaning cosolvent activated U.S • Cleaning solvent activated U.S • Rinse solvent activated U.S • Rinse solvent vapors • Drying • Unloading Ferrite Tungsten Ceramic Machine solvent TE-VSC

  11. Action of ultrasound The 3 steps of the mechanism of action of ultrasound : 1- The cavitation effect Appearance of bubbles between the substrates and greases 2- The effect of pressure Compression of the air bubble 3- Implosion of air bubbles Drop the grease from the surface Air bubbles Preparation of parts for UHV applications Frequencies used in chemical degreasing : 20 kHz for the copper and 40 kHz for the aluminum Asymmetric implosion of a cavitation bubble near a solid surface 1 2 3 IMPROVES considerably degreasing power TE-VSC

  12. Electrolytic deposition at CERN TE-VSC

  13. Why doing a deposition? COPPER PLATING : Thermal conductivity and electrical conductivity (reduction of impedance), RF Chamber BGV SILVER PLATING: Electrical conductivity (electrical contact) Low friction, seizure Contact fingers Electrolytic deposition at CERN GOLD PLATING : Chemically stable in the atmosphere and electrical conductivity Contact fingers RHODIUM PLATING: Resistant to high temperature and very high hardness (prevents galling vacuum with the couple Rh-Ag) and seizure Tube transition TE-VSC

  14. Preparation of stainless steel before deposition TE-VSC

  15. Characteristic of stainless steel Standardization of a stainless steel Mechanism passivating a stainless steel 4 Cr + 3 O2 2 Cr2O3 Ex : Stainless Steel 316 LN • Preparation of stainless steel before deposition (X2CrNiMo 17-12) X2  : Alloy steel containing 0,02 % carbon Cr : 16 – 18 % Chrome Ni : 11 – 14 % Nickel Mo : 2 – 3 % Molybdène Oxide chromium Cr2O3 TE-VSC

  16. Preparation of stainless steel prior to electroplating SULFURIC INVERSION Elimination of the passive layer WOOD NICKEL As bonding layer Stainless stell • Preparation of stainless steel before deposition + H3O+ O2 Cl- O2 O2 O2 - H2SO4 Anode nickel Stainless stell Cathode lead Ni2+ e- + - Reduction : Ni2+ + 2e- Ni Applications : Undercoat prior to electroplating Nickel plating chamber BELLOW TE-VSC

  17. Preparation of stainless steel prior to electroplating 1 1. Substrate type and geometry. 2. Study of assembly: Nature of deposit, anode assembly, masking and electrical contacts. 3. Mounting: positioning of the anode, contact verification and assembly. 4. Treatments according to operative range: monitoring the operative range. 5. Control of deposit: Aspect, deposit thickness. Electrolytic deposition at CERN 2 3 4 5 TE-VSC

  18. Electrolytic silver plating on aluminum alloys Contact Strip and Strip Line (Experiment AD) TE-VSC

  19. Plane stripline Horn + Stripline Electrolytic silver coating on aluminum alloys Silverplating 20 microns Stripline Junction Box TE-VSC

  20. Procedure Old procedure New procedure Surface preparation Degreasing / Etching Surface preparation Degreasing / Etching Step 5 Nickel-Zinc plating Step 6 Nickel Sulfamate Step 7 Pre Silver plating Step 8 Silver plating Step 5 Double-Zincate Step 6 Nickel Sulfamate Step 7 Pre Silver plating Step 8 Silver plating Electrolytic silver coating on aluminum alloys OPTIBOND CONCENTRATE Pell-off gold coating TE-VSC

  21. Characteristics of aluminum 4Al + 3O2 2Al2O3 O2 O2 O2 O2 Al2O3 Thickness 2 to 4 nm ALUMINUM ALLOYS Electrolytic silver coating on aluminum alloys (Al) Forming a thin oxide layer of alumina Equilibrium diagrams voltage-pH Aluminum-water system at 25°C Area of ​​water stability thermodynymique ALUMINUM IS AMPHOTERIC METAL TE-VSC

  22. Preparation of aluminum alloys Step 3 : Sodium Stripping Step 4 : whitening Sodium hydroxide at 40ºC Cuivre Al + 2NaOH + 2H2O 2NaAlO2 + 3H2 Nitric acid Silicium Magnesium ALUMINUM Serie 6000 (Silicium) ALUMINUM ALLOYS ALUMINUM Serie 2000 (Copper) Nitric acid + Sulfuric acid Electrolytic silver coating on aluminum alloys ALUMINUM Serie 5000 (Magnésium) Nitric acid + Fluorhydric acid Dissolution of alloying elements Dissolution of alumina TE-VSC

  23. Principe of chemical zinc (Double zincate) Step 5 : Double Zinc plating After stripping reformation of native alumina layer ZINCATE ZnO + NaOH ZnO22- -0.76 V Na+ OH- Electrolytic silver coating on aluminum alloys ALUMINUM 2Al + 3ZnO22- + 2H2O 2AlO2- + 3Zn + 4OH- Eº(V) - 1.66 V ZnO22-/Zn AlO2-/Al Formation of a chemical deposition by zinc displacement Few nanometer thickness TE-VSC

  24. Principe of chemical zinc (Double zincate) Evolution of coating weight between 1st and the 2nd Zincate Weight of the zinc layer (mg/dm2) 2ème zingage 10 9 Dissolution (HNO3) 8 7 1er zingage 6 1er 5 Electrolytic silver coating on aluminum alloys 4 3 2 1 1 1 Time (min) Provides a thinner deposit with a more compact structure TE-VSC

  25. Nickel sulfamate electroplating Step 6 : Nickel Sulfamate Nickel deposit Sulfamate 2/3 µm Deposit Zincate (a few nanometers) • Sublayer Nickel sulfamate electrolyte (dip the piece under current) ALUMINIUM Good covering power and deposition constraints Parameters : pH 5.5 Temperature : 50ºC Currents density : 2 - 16 A/dm2 Deposition rate : 0.5 µm/min to 10 A/dm2 Electrolytic silver coating on aluminum alloys Deposit Nickel sulfamate TE-VSC

  26. Silver plating Step 7 :Silver plating Moving powdery silver plating on a nickel coating (V) - + K[Ag(CN)2]- K[Ag(CN)2]- CN- + 0.80 V G Ag+ K[Ag(CN)2]- Cu2+ / Cu + 0.34 V K[Ag(CN)2]- K[Ag(CN)2]- -0.23 V Nickel metal Electrolytic silver coating on aluminum alloys Pre-Silvering : AgCN + KCN K[Ag(CN)2] Double silver cyanide (complex) Ag+ + 1e Ag Double silver cyanide enables the lowering of the potential difference between the metal surface (nickel) and silver in solution and prevents the displacement deposition. E° Reduction Ag+ / Ag Formulation [AgCN] : 4 g/L [KCN] : 90 g/L Ni Ni2+ + 2e Ag+ Ag+ Oxydation Ag+ Ni2+ / Ni 2Ag+ + Ni 2Ag + Ni2+ Reaction sheet Ag+ Ag+ Concentration Ag+ free low Nickel / Alu Silver Ag+ Silver electrolyte Pre-silvering TE-VSC

  27. Silver plating - + G Ag+ Ag+ Silvering : AgCN + KCN K[Ag(CN)2] Double silver cyanide (complex) Electrolytic silver coating on aluminum alloys Ag+ Formulation [AgCN] : 37 g/L [KCN] : 130 g/L K[Ag(CN)2]- Ag+ Pré-Argent / Alu • Strip-line AD Ag+ CN- Concentration Ag+ free high Silver K[Ag(CN)2]- Ag+ CN- Ag+ Ag+ Silvering Contact Streap (AD) The silver in a uniform power distribution and allows to obtain a deposit until 30 microns TE-VSC

  28. Improvement and development TE-VSC

  29. Analysis and water treatment plant Workshop 118 Workshop 102 Effluent Effluent Eaux Claires Boues Spectromètre d’Emission Optique (ICP-OES) TE-VSC

  30. Improvement and Development (Laboratory) Following overruns on copper water discharges : Optimization of the treatment plant - Contact providers specialized in water treatment product - Purchase of a test bench (Jar-test) - Testing of different organic precipitants - Supernatant by ICP analysis and determination of the most appropriate methods to our effluent. Analysis of the supernatant Metal hydroxide sludge Essai en Jar-test de précipitant en neutralisation Effluents after decantation TE-VSC Optical Emission Spectrometer (ICP-OES)

  31. Improvement and Development (Laboratory) Qualification of new processes for copper chemical degreasing • Contact suppliersspecialized in surface treatment • (new processes) • - Contamination of samples of copper and chemicaldegreasingsamplesaccording to procedure • - Qualification of processes by measuring the residualcarbon surface (XPS) science line t60 Analysis methods surfactants in treatment baths surface Monitoring the concentration of surfactants in chemical degreasing baths by measuring surface tension. TE-VSC

  32. Improvement and Development (Workshop) Etching for the thinning of the sample 3 (LHCb Velo) : Establishment of a procedure for etching chambers VELO (LHCb) Echantillon 3 (LHCb Velo) Achieving chamber with integrated copper electroforming layer NEG: Dévelopment of new sequences copper plating by pulsed current Tube électroformé Fabrication by electroforming nozzle gas diffusion : Electroformages of micronozzles for injecting a hydrogen micro-jet in the CERN accelerators Microbuses TE-VSC

  33. Building new surface treatment (107) planned for 2016 • THANK YOU FOR YOUR ATTENTION! TE-VSC

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