Groupe TE/VSC/SCC
SURFACE TREATMENTS AT CERN
FLORENT FESQUET PIERRE MAURIN
4 juillet 2014 TE-VSC 1/33 Outline
1. Infrastructure dedicated to surface treatment
2. Cleaning and degreasing of parts for UHV applications
3. The electrolytic deposition at CERN
- Why doing a deposition? - Preparation of stainless steel prior to electroplating - Silver plating on aluminum alloys
4. Improvement and development
4 juillet 2014 TE-VSC 2/33 Infrastructure dedicated to surface treatment
4 juillet 2014 TE-VSC 3/33 Building 867 (Site Prevessin)
Surface cleaning of large parts intended for UHV applications
Preparation copper OFE Preparation Stainless steel
Tube Max IV Tank DTL Linac 4
Preparation aluminum alloy
Chambre VJ ATLAS
Infrastructure dedicated to surface surface to treatment dedicated Infrastructure
4 juillet 2014 TE-VSC 4/33 Building 118 (Site Meyrin)
Surface preparation: chemical polishing and electropolishing of copper and Nobium
Chemical polishing of copper and niombium
Cavity HIE- ISOLDE Superconducting cavity CRAB
Electropolishing of Niobium and copper
Infrastructure dedicated to surface surface to treatment dedicated Infrastructure Superconducting cavity 5 cells Niobium for SPL (700 MHz) Copper test cavity (1300 MHz)
4 juillet 2014 TE-VSC 5/33 Building 102 (Site Meyrin)
Surface preparation of large parts intended for UHV applications
Electropolishing stainless steel
Ceramic BGV Aluminum chamber Disque of copper cavity Connector stainless steel Guide-Onde LINAC4 PIMS stainless steel Electrolytic deposition on stainless steel, copper and aluminum
Gold electroplating Copper electroplating Silver electroplating Rhodium electroplating
Couvercle Tank LINAC 4 Doigts de contact écran TDI Tube de transition LHCVSR
Infrastructure dedicated to surface surface to treatment dedicated Infrastructure Chambre LINAC
4 juillet 2014 TE-VSC 6/33 Cleaning and degreasing of parts for UHV applications
4 juillet 2014 TE-VSC 7/33 Degreasing aqueous phase
Why cleaning a part ?
GREASE GREASE
MINERAL ANIMAL
Bearing grease
Handling Packaging
MATERIAL Cutting Oil Oil pump vacuum
Eliminate grease which pollute surface.
Eliminate the solid particles present in bold (i.e. particles machining, graphite residuals…
Reduction of vacuum outgasing.
Prepare the surface before vacuum deposition or electrolytic plating. Preparation of parts for UHV applications UHV parts of Preparation for
4 juillet 2014 TE-VSC 8/33 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.
- - -
HYDROPHOBIC + + + - - + OIL + - + HYDROPHILIC + + Preparation of parts for UHV applications UHV for parts of Preparation - - - Action of an anionic surfactant Stable emulsion
4 juillet 2014 TE-VSC 9/33 Choice of degreasing processes based on materials
Solvent Machine Halogenated / hydrocarbon mixture
example of carbon chain :
Porous materials
Ferrite Tungsten Silicone valve Delicate parts Ceramic
Evaporation of the solvent
Operating range: A. Loading B. Precleaning cosolvent activated U.S C. Cleaning solvent activated U.S D. Rinse solvent activated U.S E. Rinse solvent
Preparation of parts for UHV applications UHV parts of Preparation for vapors F. Drying G. Unloading Machine solvent
4 juillet 2014 TE-VSC 10/33 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
Frequencies used in chemical degreasing : 20 kHz for the copper and 40 kHz for the aluminum
IMPROVES considerably degreasing power 1 2 3 Asymmetric implosion of a cavitation bubble near a
solid surface Preparation of parts for UHV applications UHV parts of Preparation for
4 juillet 2014 TE-VSC 11/33 Electrolytic deposition at CERN
4 juillet 2014 TE-VSC 12/33 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
GOLD PLATING : Chemically stable in the atmosphere and electrical conductivity
Contact fingers Electrolytic deposition at CERN at CERN deposition Electrolytic RHODIUM PLATING: Resistant to high temperature and very high hardness (prevents galling vacuum with the couple Rh-Ag) and seizure
Tube transition
4 juillet 2014 TE-VSC 13/33 Preparation of stainless steel before deposition
4 juillet 2014 TE-VSC 14/33 Characteristic of stainless steel
Standardization of a Mechanism passivating stainless steel a stainless steel
Ex : Stainless Steel 316 LN 4 Cr + 3 O2 2 Cr2O3 (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 Preparation of stainless steel before deposition deposition steel stainless before of Preparation
4 juillet 2014 TE-VSC 15/33 Preparation of stainless steel prior to electroplating
SULFURIC INVERSION WOOD NICKEL
Elimination of the passive layer As bonding layer
Anode nickel
Stainless stell + - + Cl 2+
H3O Ni
O O + - 2 O2 2 O2 e- H SO - 2 4 Stainless stell
Cathode lead
2+ - Reduction : Ni + 2e Ni
Applications : Undercoat prior to electroplating
Preparation of stainless steel before deposition deposition steel stainless before of Preparation
Nickel plating chamber BELLOW
4 juillet 2014 TE-VSC 16/33 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.
2 3 4 5
Electrolytic deposition at CERN at CERN deposition Electrolytic
4 juillet 2014 TE-VSC 17/33 Electrolytic silver plating on aluminum alloys
Contact Strip and Strip Line (Experiment AD)
4 juillet 2014 TE-VSC 18/33 Plane stripline
Horn + Stripline
Stripline Junction
Box Silver plating 20 microns Electrolytic silver coating on aluminum alloysaluminum on coating silver Electrolytic
4 juillet 2014 TE-VSC 19/33 Procedure
Old procedure New procedure
Surface preparation Surface preparation
Degreasing / Etching Degreasing / Etching
Step 5 Nickel-Zinc plating Step 5 Double-Zincate
Step 6 Nickel Sulfamate Step 6 Nickel Sulfamate
Step 7 Pre Silver plating Step 7 Pre Silver plating
Step 8 Silver plating Step 8 Silver plating
OPTIBOND CONCENTRATE Electrolytic silver coating on aluminum alloysaluminum on coating silver Electrolytic Pell-off gold coating
4 juillet 2014 TE-VSC 20/33 Characteristics of aluminum
4Al + 3O2 2Al2O3
O2 O2
O2 O2
Al2O3 Thickness 2 to 4 nm (Al)
Equilibrium diagrams voltage-pH Aluminum-water system at 25°C
Forming a thin oxide layer of alumina Area of water stability thermodynymique
Electrolytic silver coating on aluminum alloysaluminum on coating silver Electrolytic ALUMINUM IS AMPHOTERIC METAL
4 juillet 2014 TE-VSC 21/33 Preparation of aluminum alloys
Step 3 : Sodium Stripping Step 4 : whitening
Cuivre
Sodium hydroxide at 40ºC
Nitric acid Al + 2NaOH + 2H2O 2NaAlO2 + 3H2
Magnesium
Nitric acid + Sulfuric acid
Silicium
Nitric acid + Fluorhydric acid
Electrolytic silver coating on aluminum alloysaluminum on coating silver Electrolytic Dissolution of alloying elements Dissolution of alumina
4 juillet 2014 TE-VSC 22/33 Principe of chemical zinc (Double zincate)
Step 5 : Double Zinc plating
After stripping reformation of native alumina layer
Eº(V) 2- Na+ ZnO2 OH-
ZINCATE 2- -0.76 V ZnO2 /Zn ZnO + NaOH - - 1.66 V AlO2 /Al
2- - - 2Al + 3ZnO2 + 2H2O 2AlO2 + 3Zn + 4OH
Formation of a chemical Few nanometer deposition by zinc thickness
Electrolytic silver coating on aluminum alloysaluminum on coating silver Electrolytic displacement
4 juillet 2014 TE-VSC 23/33 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
8 Dissolution (HNO3)
7
6
5
4
3
2 1 1
Time (min)
Provides a thinner deposit with a more compact structure Electrolytic silver coating on aluminum alloysaluminum on coating silver Electrolytic
4 juillet 2014 TE-VSC 24/33 Nickel sulfamate electroplating
Step 6 : Nickel Sulfamate
Sublayer Nickel sulfamate electrolyte (dip the piece under current)
Nickel deposit Sulfamate
2/3 µm Deposit Zincate (a few nanometers)
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
Deposit Nickel sulfamate Electrolytic silver coating on aluminum alloysaluminum on coating silver Electrolytic
4 juillet 2014 TE-VSC 25/33 Silver plating
Step 7 :Silver plating Moving powdery silver plating on a nickel coating
E°(V) Nickel metal
Ag+ / Ag Ag+ + 1e Ag + 0.80 V Reduction
2+ Oxydation Ni Ni + 2e Ag+ + 0.34 V Cu2+ / Cu Ag+ Ag + Reaction sheet 2Ag+ + Ni 2Ag + Ni2+ + -0.23 V Ni2+ / Ni Ag
Silver electrolyte
Pre-Silvering : AgCN + KCN K[Ag(CN)2] Double silver cyanide (complex)
Double silver cyanide enables the lowering of the potential difference between the metal surface (nickel) and silver in solution and prevents the displacement deposition. Formulation - [AgCN] : 4 g/L + G [KCN] : 90 g/L
K[Ag(CN) ]- K[Ag(CN) ]- 2 CN- 2 Concentration Silver + Ag - Nickel / + K[Ag(CN)2] Ag free low Alu
+ Electrolytic silver coating on aluminum alloysaluminum on coating silver Electrolytic Ag K[Ag(CN) ]- - 2 Ag+ K[Ag(CN)2] Pre-silvering 4 juillet 2014 TE-VSC 26/33 Silver plating
Silvering : AgCN + KCN K[Ag(CN)2] Double silver cyanide (complex)
- Formulation + G [AgCN] : 37 g/L [KCN] : 130 g/L - K[Ag(CN)2] Ag+
Silver + Ag Ag+ - Concentration CN Ag+ Pré- Argent + - + Ag K[Ag(CN)2] / Alu Ag free + + Ag CN- high Ag+ Ag Silvering Contact Streap (AD) The silver in a uniform power distribution and allows to obtain a deposit until 30 microns
Strip-line AD Electrolytic silver coating on aluminum alloysaluminum on coating silver Electrolytic
4 juillet 2014 TE-VSC 27/33 Improvement and development
4 juillet 2014 TE-VSC 28/33 Analysis and water treatment plant
Workshop 118 Workshop 102
Effluent Effluent
Eaux Claires
Boues
Spectromètre d’Emission Optique (ICP-OES)
4 juillet 2014 TE-VSC 29/33 Improvement and Development (Laboratory)
Optimization of the treatment plant Following overruns on copper water discharges :
- Contact providers specialized in water treatment product - Purchase of a test bench (Jar-test) - Testing of different organic precipitants
Essai en Jar-test de précipitant en neutralisation - Supernatant by ICP analysis and determination of the most appropriate methods to our effluent.
Analysis of the supernatant Metal hydroxide sludge
Effluents after decantation Optical Emission Spectrometer (ICP-OES)
4 juillet 2014 TE-VSC 30/33 Improvement and Development (Laboratory)
Qualification of new processes for copper chemical degreasing
- Contact suppliers specialized in surface treatment (new processes) - Contamination of samples of copper and chemical degreasing samples according to procedure https://edms.cern.ch/document/997363/3
- Qualification of processes by measuring the residual carbon surface (XPS)
Analysis methods surfactants in treatment baths surface
Monitoring the concentration of surfactants in chemical degreasing baths by measuring surface tension.
science line t60
31/33 4 juillet 2014 TE-VSC 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 4 juillet 2014 TE-VSC 32/33 Building new surface treatment (107) planned for 2016
THANK YOU FOR YOUR ATTENTION!
4 juillet 2014 TE-VSC 33/33