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 - 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 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

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 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 % 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

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 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