Galden® PFPE

Perfluoropolyether Fluorinated Fluids

Galden® PFPE is a line of high-performance, inert, fluorinated fluids used as heat transfer and for various high-tech applications in the Electrical & Electronics and Semiconductors markets.

Key Features

  • High thermal stability
  • Wide operating temperature range
  • Good dielectric properties
  • Excellent chemical inertness
  • Good compatibility with metals, plastics and elastomers
  • No flash or fire point, no auto-ignition point
  • Safety (FM approved 6930 standard)

High Boiler Grades

Galden® High Boilers (HBs) is the family of heat transfer synthetic fluids engineered for high temperature applications which feature:

  • The highest boiling points among fluorinated heat transfer fluids
  • Very low vapor pressure and evaporation tendency
  • Outstanding non-flammability
  • Excellent chemical inertness
  • Safety (FM approved 6930 standard)

Galden® HBs are the best candidates for use at temperatures above 150° C to 270° C without pressure build-up and absolutely no fire hazard.

Among the advantages of a sound safety profile for high temperature applications is a positive impact on the Cost of Ownership.

Typical applications for Galden® HBs

  • Heat transfer management in the photovoltaic cell manufacturing process
  • Heat vector in the solar thermal industry
  • Heating fluid
  • Metallurgy
  • Energy sector

 

Factory Mutual Approved

Galden® HBs are Factory Mutual approved according to the FM 6930 standard and are available in industrial quantities.

Typical Properties

Galden® D

Thermal Shock Testing 
(not for specification purpose)

Property Units Single Fluids Dual Fluids
D02TS D03 D02 D05
Normal boiling point °C 165 203 175 230
Pour point °C -97 -85 -97 -77
Density, 25°C g/cm3 1.77 1.79 1.77 1.82
Density, -54°C g/cm3 1.95 1.96 1.95 1.98
Kinematic viscosity, 25°C cSt 1.7 2.4 1.8 4.4
Kinematic viscosity, -54°C cSt 45 160 - -
Specific heat, 25°C J/Kg°C 973 973 973 973
Thermal conductivity, 25°C W/m°C 0.07 0.07 0.07 0.07
Coefficient of expansion cm3/cm3°C 0.0011 0.0011 0.0011 0.0011
Surface tension dyne/cm 16 16 16 17
Dielectric strength kV (2.54 mm gap) 40 40 40 40
Dielectric constant   2.1 2.1 2.1 2.1
Volume resistivity Ohm-cm 5*1015 5*1015 5*1015 5*1015
Average molecular weight a.m.u. 750 870 760 1,020

Hermetic Seal Testing

Property Units Detector Fluids Indicator Fluids
DET D02 D03
Normal boiling point °C 81 175 203
Pour point °C -110 -97 -85
Density, 25°C g/cm3 1.70 1.77 1.79
Density, 125°C g/cm3 - 1.54 1.58
Kinematic viscosity, 25°C cSt 0.60 1.80 2.40
Kinematic viscosity, 125°C cSt - 0.46 0.55
Specific heat, 25°C J/Kg°C 973 973 973
Thermal conductivity, 25°C W/m°C 0.07 0.07 0.07
Coefficient of expansion cm3/cm3°C 0.0011 0.0011 0.0011
Surface tension dyne/cm 16 16 16
Dielectric strength kV (2.54 mm gap) 40 40 40
Dielectric constant   2.1 2.1 2.1
Volume resistivity Ohm-cm 5*1015 5*1015 5*1015
Average molecular weight a.m.u. 430 760 870

 

 

Galden® LS/HS
Property Units LS200 LS215 LS230 HS240 HS260
Normal boiling point °C 200 215 230 240 260
Density @ 25°C g/cm3 1.79 1.80 1.82 1.82 1.83
Kinematic viscosity @ 25°C cSt 2.50 3.80 4.40 5.30 7.00
Vapor pressure @ 25°C torr 21 12 3.4 1 1
Specific heat @ 25°C J/Kg°C 973 973 973 973 973
Heat of vap. @ BPT J/g 63 63 63 63 63
Thermal conductivity W/m°C 0.07 0.07 0.07 0.07 0.07
Coefficient of expansion cm3/cm3°C 0.0011 0.0011 0.0011 0.0011 0.0011
Surface tension dyne/cm 19 20 20 20 20
Dielectric strength kV (2.54 mm gap) 40 40 40 40 40
Dielectric constant   2.1 2.1 2.1 2.1 2.1
Volume resistivity Ohm-cm 5*1015 5*1015 5*1015 5*1015 5*1015
Average molecular weight a.m.u. 870 950 1,020 1,085 1,210
Galden® SV
Property Units SV55 SV70 SV80 SV110 SV135
Boiling point °C 55 70 80 110 135
Density g/cm3 1.65 1.68 1.68 1.71 1.72
Surface tension Dyne/cm 10 14 16 16 17
Kinematic viscosity @ 25°C cSt 0.45 0.50 0.57 0.77 1.00
Heat of vaporization BP cal/gm 22 17 17 16 16
Vapor pressure @ 20°C torr 228 165 62 0.71 0.21
Solubility of water ppm 14 14 14 14 14
Flash point °C None None None None None
Fire point °C None None None None None
Autoignition temperature °C None None None None None
ODP   0 0 0 0 0
Galden® HT - Low Boilers
Property Units Galden® 
HT55
Galden® 
HT70
Galden® 
HT80
Galden® 
HT110
Boiling point °C 55 70 80 110
Pour point °C <-115 -115 <-110 -100
Density @ 25°C g/cm3 1.65 1.68 1.69 1.71
Kinematic viscosity @ 25°C cSt 0.45 0.50 0.57 0.77
Kinematic viscosity @ 0°C cSt 0.64 0.75 0.83 1.21
Kinematic viscosity @ -20°C cSt 0.91 1.09 1.22 1.94
Kinematic viscosity @ -40°C cSt 1.40 1.79 2.00 3.74
Surface tension @ 25°C dynes/cm 16 14 16 16
Vapor pressure @ 25°C torr 225 141 105 17
Specific heat @ 25°C cal/g°C 0.23 0.23 0.23 0.23
Thermal conductivity @ 25°C W/m°C 0.065 0.065 0.065 0.065
Heat of vaporization @ boiling point cal/g 22 17 17 17
Dielectric strength @ 25°C KV (2.54mm gap) 40 40 40 40
Dissipation factor @ 25°C 
(1 kHz)
  2*10-4 2*10-4 2*10-4 2*10-4
Dielectric constant @ 25°C 
(1 kHz)
  1.86 1.88 1.89 1.92
Volume resistivity O.cm 5*1015 5*1015 5*1015 5*1015
Solubility of water ppm (wt) 14 14 14 14
Solubility of air cm3gas/ 
100 cm3liquid
26 26 26 26
Refractive index @ 25°C   1.280 1.280 1.280 1.280
Coefficient of expansion cm3/cm3°C 0.0011 0.0011 0.0011 0.0011
Average molecular weight   340 410 430 580
Galden® HT - High Boilers
Property Units Galden® 
HT135
Galden® 
HT170
Galden® 
HT200
Boiling point °C 135 170 200
Pour point °C -100 -97 -85
Density @ 25°C g/cm3 1.72 1.77 1.79
Kinematic viscosity @ 25°C cSt 1.0 1.8 2.4
Kinematic viscosity @ 0°C cSt 1.69 3.41 4.97
Kinematic viscosity @ -20°C cSt 2.92 7.11 11.65
Kinematic viscosity @ -40°C cSt 6.32 21.14 -
Surface tension @ 25°C dynes/cm 17 18 19
Vapor pressure @ 25°C torr 5.8 0.8 0.2
Specific heat @ 25°C cal/g°C 0.23 0.23 0.23
Thermal conductivity @ 25°C W/m°C 0.065 0.065 0.065
Heat of vaporization @ boiling point cal/g 16 16 15
Dielectric strength @ 25°C KV (2.54mm gap) 40 40 40
Dissipation factor @ 25°C (1 kHz)   2*10-4 2*10-4 2*10-4
Dielectric constant @ 25°C (1 kHz)   1.90 1.90 1.94
Volume resistivity O.cm 5*1015 5*1015 5*1015
Solubility of water ppm (wt) 14 14 14
Solubility of air cm3gas/ 
100 cm3liquid
26 26 26
Refractive index @ 25°C   1.280 1.280 1.281
Coefficient of expansion cm3/cm3°C 0.0011 0.0011 0.0011
Average molecular weight   610 760 870
Property Units Galden® 
HT230
Galden® 
HT270
Normal Boiling point °C 230 270
Density @ 25°C g/cm3 1.82 1.85
Kinematic viscosity @ 25°C cSt 4.4 11.7
Vapor pressure @ 25°C torr 0.025 3*10-3
Specific heat @ 25°C cal/g°C 0.23 0.23
Thermal conductivity @ 25°C W/m°C 0.65 0.65
Heat of vaporization @ boiling point cal/g 16 15
Dielectric strength @ 25°C KV (2.54mm gap) 40 40
Dissipation factor @ 25°C (1 kHz)   2*10-4 2*10-4
Dielectric constant @ 25°C (1 kHz)   1.94 1.94
Volume resistivity O.cm 5*1015 5*1015
Solubility of water ppm (wt) 14 14
Solubility of air cm3gas/ 
100 cm3liquid
26 26
Coefficient of expansion cm3/cm3°C 0.0011 0.0011
Average molecular weight   1,020 1,550
Appearance   Clear and odorless Clear and odorless

Frequently Asked Questions

 

What is Galden® PFPE?

Galden® fluids are low molecular weight Perfluoropolyether (PFPE) having the following general structure:

Galden® PFPE is a line of dielectric fluids with boiling points ranging from 55 °C to 270 °C and a typical operating range from – 70 °C to 270 °C.

Galden® PFPE fluids are high performance, inert fluids characterized by:

  • High thermal stability (up to + 290 °C)
  • The highest boiling point among fluorinated fluids (up to + 270 °C)
  • Very good dielectric strength and volume resistivity properties
  • Excellent chemical inertness
  • Good compatibility with metals, plastics, and elastomers
  • No flash or fire point, no autoignition point
  • Safe. Galden® PFPE fluids are NSF approved
What are the Typical Industrial Applications for Galden® PFPE?

Their excellent dielectric properties, high chemical stability combined with their capacity to operate at very low as well as elevated temperatures and in aggressive conditions make them useful in many industrial applications.

Typical industries served by Galden® PFPE fluids are semiconductor manufacturing, electronic testing and cooling, cleaning, carriers for fluorinated lubricants, solar, CPI, batteries, pharmaceutical and food.

  • Heat Transfer (HT grades)
  • Electronic Testing (D grades)
  • Vapour Phase Soldering/Heating (LS – HS grades)
  • Solvents (SV grades)

 

Heat Transfer

galden-heat-transfer

The products offered for use in heat transfer applications are called Galden® HT. This is a line of dielectric fluids with boiling points ranging from 55 °C to 270 °C. Galden® PFPE excellent dielectric properties, high chemical stability combined with their capacity to operate at very low as well as elevated temperatures make them the best heat transfer fluids for the aggressive conditions found in many semiconductor processes, electronic, and solar industries.

Electronic Reliability Testing

Non-reactivity, excellent dielectric properties, low toxicity, non-flammability, and non-solvent features make Galden® D electronic fluids suitable for electronic reliability testing including thermal shock and hermetic seal testing.

Thermal shock testing

galden-thermal-shock-testing

Thermal shock testing is performed to check the resistance of electronic devices to extreme changes of temperature; often used for automotive and in the military applications. Here are some of the standards often referenced: MIL STD 883 method 1011 or MIL STD 202 method 107. The test is carried out by alternately dipping the devices in liquids maintained at two different temperatures; many applications test devices at 65 °C and 150 °C or higher. Galden® D fluids can be used both for single and dual fluids systems.

Hermetic seal test

galden-hermetic-seal-testing

Electronic devices must be completely sealed to avoid moisture to penetrate and damage the electrical response of the silicon chip. Here are some of the standards often referenced: MIL STD 883, MIL STD 750 and MIL STD 202. Galden® D fluids being extremely inert and residue-free are currently used as detector and indicator fluids in leak test procedure.

Vapor Phase Soldering

galden-vapor-phase-soldering

VPS’ principle is to use the latent heat of condensation of Galden® PFPE vapors in order to melt solder paste and hence to obtain reliable metal joints. The narrow molecular weight distribution, as well as the very strong carbon-fluorine bond containing no bromines, and the flexible ether link provide the properties which make Galden® LS/HS ideal for use in VPS.

Solvent

Galden® SV fluids are low molecular weight perfluoropolyether fluids that have no flash point and are inert, non-toxic, odorless and colorless. They are used for cleaning operations where solvents are:

  • Applied to hot components
  • Heated prior to application
  • Pressure sprayed onto components
What is the Typical Temperature Range for Use of Galden® PFPE?

Galden® PFPE is a line of dielectric fluids with boiling points ranging from 55 °C to 270 °C.

For heat transfer application the working temperature ranges are reported in the graph below and the temperature limits are set as follows:

  • The lower temperature limit is set when the fluid viscosity reaches the value of 20 cP (11 – 12cSt). This is typically the operating range of many commercially available fluid pumps.
  • The upper limit is set at 10 °C below the boiling point of the fluid itself.

Operating temperature range

galden-operating-temparature-range
What is the Pour Point of Galden® PFPE?

The pour point is the lowest temperature at which a fluid will flow. This property is crucial for fluids that must flow at low temperatures. A commonly used rule of thumb when selecting fluids is to ensure that the pour point is at least 10 °C lower than the lowest anticipated ambient temperature. Galden® HT line of fluids offers a wide range of very low temperatures pour points from – 115 °C to – 66 °C.

Grade Pour Point [°C]
Galden® HT55 –110
Galden® HT70 –105
Galden® HT80 –100
Galden® HT110 –100
Galden® HT135 –100
Galden® HT170 –97
Galden® HT200 –85
Galden® HT230 –77
Galden® HT270 –66
What is the Density of Galden® PFPE?

The density of a material is defined as its mass per unit volume. Density at 20 °C for Galden® PFPE grades is the following:

Grade Density [g/cm3]
Galden® HT55 1.66
Galden® HT70 1.69
Galden® HT80 1.69
Galden® HT110 1.72
Galden® HT135 1.73
Galden® HT170 1.78
Galden® HT200 1.80
Galden® HT230 1.83
Galden® HT270 1.86
What is the Viscosity Range of Galden® PFPE?

Viscosity is an internal property of a fluid that offers resistance to flow. The viscosity of a liquid usually depends on its temperature. Viscosity generally decreases as the temperature increases and generally increases as the temperature decreases. For many heat transfer applications the lower temperature limit (pumpability limit) is set when the fluid viscosity reaches the value of 20 cP (11 – 12 cst).

Kinematic viscosity vs. temperature

galden-kinematic-viscosity-vs-temperature
Is Galden® PFPE Flammable?

No, Galden® PFPE are not flammable. They don’t have flash, fire or autoignition point.

  • Galden® PFPE fluids are Factory Mutual Underwriters approved.
  • Galden® PFPE fluids are complaint to FM 6930 Approval Standard Fluids.
fomblin-pfpe-fm-certificate
Is Galden® PFPE Hazardous?

No, Galden® PFPE are very safe fluids:

  • No flash or fire point
  • No explosion hazard
  • No toxicity
  • No autoignition point
  • Thermal, oxidative & chemical stability
  • Shelf life over 20 years

 

Galden® PFPE are stable in thermal conditions above 300 °C. In the presence of oxygen the continuous use temperature of these fluids is somewhat lowered to 290 °C. Up to these temperatures, the decomposition of the fluids is negligible. Galden® PFPE can be stored and handled without specific precautions, do not react with chemicals and refrigerants and does not get oxidized.

What is the Degradation Temperature of Galden® PFPE?

Galden® PFPE are stable in thermal conditions above 300 °C. In the presence of oxygen the continuous use temperature of these fluids is somewhat lowered to 290 °C. Up to these temperatures, the decomposition of the fluids is negligible.

Do Galden® PFPE Cause Corrosion?

No. Galden® PFPE do not corrode metals because they interrupt the electrical circuit that is the base for the corrosion process: the conducting environment for ionic movement is disabled by the high volume resistivity of Galden® PFPE fluids that does not vary over time (the volume resistivity of DI water is at least 107 Ω · cm, and this value tends to reduce over time – DI water extracts metal ions).

Property Galden® PFPE DI-Water
Volume Resistivity (Ω · cm) > 1015 < 107

Corrosion in Galden® PFPE heat transfer systems can generally be linked to either a separate water phase or thermal decomposition of the fluid. In order to have a separate water phase the amount of water in the system must be beyond the saturation level of the fluid. The saturation level of water in a Galden® PFPE fluid is usually less than 20 ppm by weight. Water present in the fluid at or below this level has never been linked to corrosion. Water present above this level means a separate water phase. If such water is entrained into contact with metal parts, corrosion can be rapid. Water can enter heat transfer systems in a few different ways: components can be hydrotested and never dried before installation.

Thermal decomposition of the fluid: fluoride ion can be generated any time the fluid is brought above its decomposition temperature and this can lead to corrosion. Thermal degradation for Galden® PFPE start at about 290 – 300 °C. HF can be generated only when the fluid is brought above its decomposition temperature and these conditions are far from the working temperature range. Experience indicates that corrosion resulting from decomposition is very rare and is only observed in systems which have undergone a failure. Examples include: a burned out heater, high voltage discharge in dielectric systems or a burned out electrical component in a direct contact electrical application.

What are the Electric Properties of Galden® PFPE?

Galden® PFPE fluids are excellent dielectrics. This is the main reason they are used in many applications.

Property Unit Value
Dielectric strength kV at 2.54 mm gap 40
Volume resistivity Ohm·cm 1.5·1015
What is the Solubility of Water in Galden® PFPE?

The saturation level of water in a Galden® PFPE fluid is usually less than 20 ppm by weight.

Is Galden® PFPE Compatible with Various Materials?

Galden® PFPE fluids are increasingly used as heat transfer fluids, especially in the tools used in semiconductor manufacturing. They are fluorinated fluids and their excellent dielectric properties, high chemical and thermal stability combined with their capacity to operate at very low as well elevated temperatures make them the best heat transfer fluids for the aggressive conditions used in semiconductor manufacturing.

The compatibility of a fluid with various materials is strongly dependent on the fluid properties.

Galden® PFPE Fluid Properties

Surface tension

Surface tension is a measure of the fluid to wet other materials – the lower the surface tension, higher is the wetting power. Galden® PFPE fluids have low surface tension and are capable of wetting almost all the conventional sealing and gasket materials. This allows the fluids to creep out of very small leak paths. The best sealing materials should have low surface energies in order to minimize wetting.

Chemical and physical compatibility

In spite of the excellent compatibility, due to the low surface tension, these fluids could penetrate the elastomers and plastics and cause swelling and/or extraction of plasticizers and fillers. Swelling could have a positive effect on sealing, but the sealing could fail if the joint is opened for maintenance or other purposes. It is recommended that a new seal or gasket material is used if excessive swelling is noticed. The extraction of plasticizers would reduce the elasticity of the seals, gaskets, hoses and tubes. The material could turn rigid and become brittle. This problem could become severe if there is temperature cycling.

Dielectric properties and static electricity build-up

Galden® PFPE fluids are excellent dielectric fluids and possess high electrical resistivity. This property that makes these fluids very attractive for their use in semiconductor manufacturing tools that use Rf energy, has one negative effect – potential to build-up of static electricity when these fluids flow on non-conductive materials such as plastics and elastomers. The build-up static electricity, when reaching high values, will discharge into the surroundings with arcing. This could cause pinholes in hoses and tubes causing the fluid to leak.

The build-up and discharge of static electricity depend on many factors such as nature of the material, flow velocity, surrounding humidity etc. and is very difficult to reproduce in the laboratory. One of the properties that determines the dissipation of the built of electrostatic charges is the conductivity of the fluid as well as that of the tube or the hose in which the fluid flows. One would expect a quicker dissipation with the increased conductivity. Conductive hoses and tubes with good grounding have been and are being used in the industry with good success. The conductivity of the fluid could be increased by suitable additives as done with gasoline. However, additives may affect the dielectric properties of the fluid and may be absorbed by filters in the system.

Materials of Construction

The commonly encountered materials of construction can be classified into elastomers, plastics and metals. Before selecting these materials, it is important to verify if they are recommended for the temperature range of interest. The compatibility of these materials with the fluids depends on the base material and the formulations used in making the seals, gaskets and hoses as well as the operating temperatures and temperature cycling.

The compatibility of the pure materials could be different from that of the seals and gaskets that are formulated with these materials. Different formulated products based on the same base material could have different compatibility. Hence it is very difficult to make general statements about the compatibility. Often compatibility tests have to be performed with the formulated seals and gaskets.

Fluorinated elastomers and plastics

Fluorinated elastomers include Tecnoflon® FKM/FFKM produced by Solvay Specialty Polymers, Viton® produced by DuPont and Fluorosilicones. Fluorinated plastics include Algoflon® PTFE, Hyflon® MFA®, and Hyflon® PFA produced by Solvay Specialty Polymers and Teflon® produced by DuPont. Typically fluorinated products have low surface energies and hence are difficult to wet. They make good seals against Galden® PFPE. However, compatibility of the seals and gaskets made out of these materials with Galden® PFPE a under operating conditions should be confirmed before using them. For example Kalrez® is an expensive, specialty fluorinated material, but its physical compatibility with Galden® PFPE fluids is very poor.

Non-fluorinated elastomers and plastics

Among the non-fluorinated materials, silicones have the lowest surface energy and hence make leakproof seals and gaskets for the Galden® PFPE. As in the case of fluorinated materials, the compatibility under operating conditions should be confirmed. Hoses and tubes made of other materials such as NBR, BR, EPDM, PB etc. have been successfully used; it is important to confirm that leaching of plasticizers will not be an issue with these hose materials.

Conductive plastics

The build-up and discharge of static electricity is an important phenomenon that should be controlled in order to avoid pinholes and subsequent fluid losses. Where metal tubes cannot be used, conductive hoses with suitable grounding have been successfully used to eliminate problems related to static electricity build-up. When using these conductive materials, in addition to swelling and changes in the mechanical properties of the materials, leaching of the conductive filler should also be considered. Generally, using carbon fillers increases the conductivity of plastics. Some hoses have a thin layer of carbon deposited on the plastic. The latter have not been found to be very useful due to the breaking down of the carbon layer caused by fluid attrition with time. The carbon so liberated could deposit on undesired parts of the tool.

Metals

Galden® HT, if properly used, i.e. far from thermal degradation temperature and in waterfree system, are fully compatible with metals commonly encountered in TCUs or chillers; they do not corrode and do not react with construction materials. Compatibility tests with different metals and at different temperatures have been carried out and no evidence of corrosion or reaction were detected. With reference to AlMgSi alloy and Stainless Steel 1.4404, based on our experience and knowledge we do not expect any adverse reaction.

Compatibility Tests

Test conditions: Compatibility tests have been carried out using pure Galden® PFPE at 200 °C for 500 hrs.

  • Appearance and weight changes of metal specimen were determined
  • Acidity and viscosity of the fluid were checked as well
Metal Result
Stainless Steel 1.4301 Compatible
Stainless Steel 1.4404 Compatible
Iron Compatible
Nickel Compatible
Copper Compatible
Brass Compatible
AlMgSiCu* Compatible

*test carried out at 90 °C per customer’s request

Valves and fittings

Once again, the unique properties of these fluids and the unusual conditions under which they operate, make it necessary to pay particular attention to the selection of valves and fittings. Valves with static seals have shown to be very effective in reducing fluid losses due to leakage. Swagelok, a leading manufacturer of valves and fittings has carried out several tests with Galden® PFPE fluids. These tests included higher system pressures, temperature cycling and leak rate measurements. The major reason for fluid leakage is the dynamic seal in a plug valve. This problem could be overcome by the use of ball valves with static flange seals. Silicone seals have shown good performance over a wide range of temperatures.

Conclusions

Fluid leakage due to poor material compatibility and poor choice of seals and gaskets could amount to thousands of dollars as well as to undesired loading of environment. Solvay Specialty Polymers has carried out compatibility tests in their laboratories and also work closely with manufacturers of OEM tools, thermal control units (chillers and heat exchangers) and system components such as pipes, seals & gaskets and valves & fittings.

 

 

What Types of Materials IS NOT an Issue?

As a general rule the following tab can be followed:

Metals Plastics Elastomers
AISI 316 PE low density Butyl rubber
Copper Polypropylene NBR
Brass Polycarbonate EPDM
Iron ABS copolymer Natural rubber
Nickel Polyphenyloxide Silicone rubber
Aluminum PET  
  PTFE  
  PMMA  

The compatibility of the pure materials (i.e. elastomers) could be different from that of the seals and gaskets that are formulated with these materials. Different formulated products based on the same base material could have different compatibility. Hence it is very difficult to make general statements about the compatibility. Often compatibility tests have to be performed with the formulated seals and gaskets.

Galden® PFPE Fluid Compatibility with Plastics

The following plastics (not formulated) were unchanged after immersion in Galden® PFPE for 1,000 hrs at 70 °C:

  • Acetal copolymer (POM)
  • Acrylonitrile-butadienestyrene copolymer (ABS)
  • Phenylene-oxide based resins (PPO)
  • Polyamide 6,6 (Nylon 6,6)
  • Polybutylene terephthalate (PBT)
  • Polycarbonate (PC)
  • Polyethylene high density (HDPE)
  • Polyethylene low density (LDPE)
  • Polyethylene terephthalate (PET)
  • Polypropylene (PP)
  • Polystyrene (PS)
  • Polystyrene impact resistant (HIPS)
  • Polyvinyl chloride (PVC)
  • Polyvinyliden sulfide (PVDS)
  • Styreneacrylonitrile copolymer (SAN)
How Do I Select a Fluid for a HT Application?

We suggest selecting a HT fluid according two main parameters:

Viscosity at the lowest operating temperature

  • Typical value < 20 cp or < 10 – 12 cSt for fluorinated fluids for pump-ability

 

Vapor pressure at the highest operating temperature

  • Suggested boiling point of fluid at least 10 °C higher than the highest operating temperature in order to:
    • Avoid excessive pressure in the HT circuit
    • Reduce fluid losses
    • Reduce cavitation
What is Heat Transfer Factor (HTF) and Pressure Drop (Fρ)?

Two factors have been introduced in order to evaluate the heat transfer properties of a fluid flowing in a system without knowing the geometry of it.

Heat Transfer Performance can be predicted by means of:

  • Heat Transfer Factor (HTf)
  • Pressure Drop Factor (Fρ)

 

Both factors are function of fluid properties and are subjected to change with temperature. HTf and Fρ can be plotted vs. temperature and used for comparing fluids (given the same geometry of TCU and flow conditions).

Heat Transfer Factor (HTf): HTf = 0.023 · k 0.67 · (r ·cp) 0.33 · n – 0.47

where: 
k = Thermal conductivity 
r = Density 
cp = Specific heat 
n = Kinematic viscosity

HTf compares the capacity of fluid to add or remove heat under fully developed turbulent flow conditions (Re > 10,000) for a given geometry.

Higher the HTf, better is the heat transfer efficiency.

galden-pfpe-heat-transfer-factor

Pressure Drop Factor (Fρ): Fρ = 0.092 · ρ · ν 0.2

where: 
ρ = Density 
ν = Kinematic viscosity

A lower Fρ relates to reduced frictional losses, given the same fluid velocity and tube geometry.

Higher the Fρ, the higher is the pumping power required.

galden-pfpe-pressure-drop-factor

 

How Do I Size a Heater for Use with Galden® PFPE Fluids?

For Galden® PFPE grades, a general recommendation is not to install a heater watt density higher than 4 ÷ 5 W/cm2, in order to avoid instability in heater surface temperature for low flow units (i.e. fluid reservoir in the TCU). Having the heater section where fluid flow is present near the outlet of the pump, it will allow higher watt density heaters to be used. The critical breakdown is ~ 14 W/cm2. We recommend 4 W/cm2. The decision to go beyond this level should be made by the customer.

What is the Difference Between Galden® HT and Galden® LS/HS?

Galden® LS/HS fluids are specifically designed for vapor phase soldering process. A strict control of the molecular weight distribution and of the vapors temperature is performed by measuring respectively:

  • Distillation range (ASTM D1078)
  • Boiling temperature (TRV ASTM D1120)

 

The above characteristics are always included in the material specifications:

Property LS200 LS215 LS230 HS240 HS260
Distillation range [°C] 196–212 212–223 222—235 237–250 256–273
Boiling temperature TRV [°C] 194–200 212–218 227–233 237–243 260–265

The sharp molecular weight distribution eliminates the preferential evaporation of low boiling components during VPS process. This phenomenon leads to higher losses of the fluids as well as a shift towards higher vapor temperature with time ► undesired boiling point drift.

galden-ls-hs-comparsion

 

What is the Difference Between Boiling Point, TRL and TRV?

The boiling point of an element or a substance is the temperature at which the vapor pressure of the liquid equals the environmental pressure surrounding the liquid. Boiling temperature for each fluid is determined according test method ASTM D1120. TRL means Temperature Reflux Liquid and it is a value worth for HT Fluids. TRV means Temperature Reflux Vapor and it is a value worth for HS and LS Fluids.

galden-boiling-point

 

How Can I Detect Fluid Leaks?

Even at room temperature Galden® PFPE fluids have a vapor pressure value higher than 0 Torr, so they release vapors even if at negligible rate, depending by grade. In order to detect fluid leaks a halogen leak detector can be used; these are available through most commercial refrigeration supply centers.

Are Galden® PFPE Fluids Food Grade Approved?

Galden® PFPE fluids are NSF approved all with the related intended use described below.

  • H1: General, incidental contact
  • HT1: Heat transfer fluids, incidental contact
  • HTX1: Ingredients for use in HT1 heat transfer fluids
  • HX1: Ingredients HX1 for use in H1 lubricants, incidental contact

 

Approved fluids:

  • Galden® HT 55
  • Galden® HT 70
  • Galden® HT 80
  • Galden® HT 110
  • Galden® HT 135
  • Galden® HT 170
  • Galden® HT 200
  • Galden® HT 230
  • Galden® HT 240
  • Galden® HT 270
Do Galden® PFPE Fluids Satisfy MIL Requirements?

Yes. Galden® PFPE fluids satisfy MIL requirements. Hermetic seal testing is performed to check hermetic devices.

Leak test procedure is performed according to:

  • MIL STD 883, method 1014K
  • MIL STD 750, method 1071
  • MIL STD 202, method 112
MIL Standards recommendations for testing fluid properties
Appearance Clear and colorless
Density at 25 °C > 1.6 gm/cm3
Dielectric strength at 2.54 mm > 30 kV
Viscosity profile According the equipment manufacturer
Residue < 50 ppm
Composition* NO chlorine and NO hydrogen

*It is not a restriction; the use of products having chlorine or hydrogen is allowed

What is the shelf life for Galden® PFPE?

The real shelf life of Galden® PFPE as far as the chemical stability is concerned is over 20 years based on our experience. Within this time frame the above products, if stored under normal condition in original sealed containers, maintain their chemical-physical properties unchanged.

Heat Transfer Fluids

The main purpose of a process cooling fluid is to control or maintain the constant temperature of the wafer to a certain set point in order to avoid potential material damage.

Galden® PFPE HT is a line of heat transfer fluids with boiling points ranging from 55°C to 270°C. Their excellent dielectric properties, high chemical stability combined with their capacity to operate at very low as well as elevated temperatures make them the best heat transfer fluids for the aggressive conditions used in the Semiconductor and Electronic Industry.

Galden® PFPE HT fluids show excellent compatibility with most of the materials commonly present in heat exchangers. Galden® PFPE systems are practically maintenance-free with no corrosion hazard. Galden® PFPEdielectric properties do not change with use with no risk of short circuiting. Environmentally safe, Galden® PFPE is non-toxic, non-explosive, and will not damage electronics should any leakage occur. No Flash or Fire Point and No Auto-ignition Point are additional advantages of Galden® PFPE HT.

Galden® HT PFPE: operating temperature range

galden-ht-pfpe-operating-temparature-range

 

Electrical/Electronics Production Equipment

Vapor Phase Soldering Fluids

When the chips are packaged and tested, they must be assembled on mother boards. Vapor Phase Soldering (VPS) uses the latent heat of condensation of Galden® PFPE vapors in order to melt solder paste and hence to obtain reliable metal joints. Solder traditionally used ~ 60% of tin (Sn) and ~ 40% of lead (Pb).

Now alternative solder materials have been introduced; the most common replacements for lead are silver (Ag), Copper (Cu) and Bismuth (Bi). These alternative materials, however, bring a challenge: higher melting temperature. Traditional tin/lead solders melt at ~ 180°C while lead free solder melts at ~227°C. Soldering temperatures are, as well as heating issues, ongoing concerns for PCBs assemblers.

Galden® PFPE LS / HS is a line of fully fluorinated fluids specifically designed for the VPS process with the following properties:

  • The narrow molecular weight distribution
  • Very strong carbon-fluorine bond
  • Flexible ether link

Galden® PFPE LS and HS fluids precise vapor temperature eliminates overheating, offering the widest temperature range to lead free solders up to 260°C and are RoHS compliant.

 

Thermal Shock Testing

Thermal shock testing is performed to check the resistance of electronic devices to extreme changes in temperature. The test is carried out by alternately dipping the devices in liquids maintained at two different temperatures. For military applications the thermal shock test must be performed as specified in MIL STD 883 method 1011 or MIL STD 202 method 107.

Traditionally two different fluids can be used in the hot and cold bath but the Dual Fluid System presents several disadvantages. A Single Fluid System is possible with Galden® PFPE fluids because they can operate at very low as well as elevated temperatures. This Single Fluid System for both baths allows for a dramatic decrease in operating costs by:

  • Limiting fluid consumption
  • Reducing equipment downtime
  • Eliminating cross contamination
  • Reducing inventory to a single product

Galden® PFPE D02TS and D03 are the single fluids which can successfully replace the need for a Dual Fluid System.

Galden® D02TS is proposed for all military applications; it meets the MIL STD 883 and MIL STD 202 while for all non-military applications Galden® PFPE D03 may be suitable.

 

Galden® PFPE Fluids for Thermal Shock Testing Conforming to MIL STD 883

Test Condition Hot Step 
[°C]
Cold Step 
[°C]
Hot Bath 
Fluid
Cold Bath 
Fluid
B +125 -55 D02 
D02TS
DET  
D02TS
C +150 -65 D02 
D02TS
DET  
D02TS
D +200 -65 D05 DET
E +150 -195 D02 
D02TS
Liquid N2
F +200 -195 D05 Liquid N2

Hermetic Seal Testing

Electronic devices must be completely sealed to avoid penetration by moisture and potential damage to the electrical response of the silicon chip. To guarantee the hermeticity of devices, a leak test procedure has been defined by MIL STD 883, MIL STD 750 and MIL STD 202. Galden® PFPE fluids, being extremely inert and residue-free, are ideal and widely used as detector and indicator fluids in leak test procedures.

Galden® PFPE DET: detector fluid specifically designed for high reliability measures. Thanks to its perfect balance between low and high boilers components, it can easily detect large and small leaks. High boilers enter through large leaks and remain liquid until the test is performed while low boilers can easily penetrate into small leaks.

Galden® PFPE D02 and D03 are low consumption indicator fluids advantageously used as Indicator fluids respectively in military and non-military applications. They show an higher boiling point and a lower vapor pressure at test temperature

 

Galden® PFPE Fluids for Gross Leak Test Conforming to MIL STD

Fluid Type Type I 
Detector
Type II 
Indicator
Type III 
Detector
Test Condition C1, C3 C1 E
Galden® Fluids DET D02 DET

 

 

Semiconductor Test, Assembly & Packaging

Vapor Phase Soldering Fluids

Electronic devices must be completely sealed to avoid penetration by moisture and potential damage of the electrical response of the silicon chip. To guarantee the hermeticity of devices, a leak test procedure has been defined and ruled by MIL STD 883, MIL STD 750 and MIL STD 202.

Galden® PFPE fluids, extremely inert and residue free, are ideal and widely used as detector and indicator fluids in leak test procedures.

Galden® PFPE DET, the detector fluid specifically designed for high reliability methods thanks to its perfect balance between low and high boiler components, can easily detect large and small leaks. High boilers enter through large leaks and remain liquid until the test is performed while low boilers can easily penetrate into small leaks.

Galden® PFPE D02 and D03 are low consumption indicator fluids which can be advantageously used as indicator fluids respectively in military and non-military applications thanks to their higher boiling point and lower vapor pressure at test temperatures.

Thermal Shock Testing

Thermal shock testing is performed to check the resistance of electronic devices to extreme changes in temperature. The test is carried out by alternately dipping the devices in liquids maintained at two different temperatures. For military applications thermal shock test is performed as specified in MIL STD 883 method 1011 or MIL STD 202 method 107.

Traditionally two different fluids can be used in the hot and cold bath, but this practice presents several disadvantages.

Galden® PFPE fluids can operate at very low as well as elevated temperatures, and their Single Fluid System is an advantageous alternative to the Dual Fluid Solution.

A single fluid for both baths allows for a dramatic decrease in operating costs by decreasing fluid consumption, reducing equipment downtime, eliminating cross contamination and reducing inventory to a single product.

Galden® PFPE D02TS and D03 are the single fluids which can successfully replace a dual fluid system.

Galden® PFPE D02TS is proposed for all military applications; it meets MIL STD 883 and MIL STD 202 while for all non-military applications Galden® PFPE D03 may be suitable.

Test Condition Hot Step 
[°C]
Cold Step 
[°C]
Hot Bath 
Fluid
Cold Bath 
Fluid
B +125 -55 D02 
D02TS
DET  
D02TS
C +150 -65 D02 
D02TS
DET  
D02TS
D +200 -65 D05 DET
E +150 -195 D02 
D02TS
Liquid N2
F +200 -195 D05 Liquid N2

Hermetic Seal Testing

Electronic devices must be completely sealed to avoid penetration by moisture and potential damage to the electrical response of the silicon chip. To guarantee the hermeticity of devices, a leak test procedure has been defined by MIL STD 883, MIL STD 750 and MIL STD 202. Galden® PFPE fluids, being extremely inert and residue-free, are ideal and widely used as detector and indicator fluids in leak test procedures.

Galden® PFPE DET: detector fluid specifically designed for high reliability measures. Thanks to its perfect balance between low and high boilers components, it can easily detect large and small leaks. High boilers enter through large leaks and remain liquid until the test is performed while low boilers can easily penetrate into small leaks.

Galden® PFPE D02 and D03 are low consumption indicator fluids advantageously used as Indicator fluids respectively in military and non-military applications. They show an higher boiling point and a lower vapor pressure at test temperature

 

Galden® PFPE Fluids for Gross Leak Test Conforming to MIL STD

Fluid Type Type I 
Detector
Type II 
Indicator
Type III 
Detector
Test Condition C1, C3 C1 E
Galden® Fluids DET D02 DET
Electronic Reliability Testing

Non-reactivity, excellent dielectric properties, non-toxicity, non-flammability, and non-solvent features make Galden® D PFPE electronic fluids suitable for electronic reliability testing including thermal shock and hermetic seal testing.

Galden® PFPE Fluids for Gross Leak Test

Fluid Type Type I 
Detector
Type II 
Indicator
Type III 
Detector
Test Condition C1, C3 C1 E
Galden® Fluids DET D02 DET

 

Fuel Cells

Heat Transfer, Testing and Cooling

Galden® HT PFPE exhibits characteristics that make it the safest dielectric fluids for fuel cell:

  • High thermal stability 
  • Chemical inertness 
  • No flash or fire point (FM 6930 listed)
Acid Spill Mitigation

A sulphuric acid spill is a critical event which requires prompt mitigation of dangerous vapor formation and release. The right mitigation media ought to be used to act effectively and eventually avoid adding further complications.

Galden® PFPE materials have excellent chemical inertness, are highly hydrophobic, have a high density while still lower than oleum, and are non flammable. In addition, Galden® PFPEs are completely immiscible with oleum.

Galden® PFPEs can be a suitable solution to create a continuous blanket material for oleum, sulphuric trioxide and sulphuric acid spill mitigation.

Solar Energy

Heat Transfer Fluids

Galden® PFPE fluids include a family of Ultra High Boilers (UHB), perfluoropolyethers specifically engineered for the high temperature applications typical of the PV and solar industries.

Key features

  • Highest boiling point among all the fluorinated fluids
  • Extremely wide operating temperature range (-70°C to +290°C)
  • Excellent safety profile
  • Outstanding chemical inertness
  • No pressure build-up
  • No fire and no explosion hazards

Typical applications 

  • Temperature control management of the manufacturing processes of crystalline and thin film PV solar cells Heat transfer fluids in the 
  • Solar Thermal and Concentrated Solar Power (CSP) industry 
  • Direct coolant in Hybrid PV/T and concentrated PV
Solvent

Galden® SV PFPE are low molecular weight perfluoropolyether fluids used as carrier fluids for PFPE lubricants and for cleaning operations when:

  • Applied to hot components
  • Heated prior to application
  • Pressure sprayed onto components

 


Vapor Pressure vs. Temperature

galden-vapor-pressure-vs-temperature