MT-704 diffusion pump fluid is a single component fluid for high vacuums of 10E-6 to 10E-8 torr, untrapped or 10E-10 to 10E-11, trapped. It performs well in tough, rugged applications and offers quick pumpdown, even after exposure to air at operating temperatures, although this is not recommended. Replacement for and equivalent to Dow Corning DC-704. Sold as DS-704 and Invoil 704 elsewhere.
MT-702 and MT-705 are available in separate listings.
SPECIFICATION | MT-702 | MT-704 | MT-705 |
Molecular Description | Mixed phenylmethyl dimethyl cyclosiloxane | Tetramethyl tetraphenyl trisiloxane | Pentaphenyl trimethyl trisiloxane |
Color | Clear | Light Straw | Clear/Light Straw |
Ultimate Untrapped Vacuum (torr) | 10E-5 | 10E-7 to 10E-8 | 5 E-9 |
Ultimate Trapped Vacuum | – | to 10E-11 | to 10E-11 |
Extrapolated Vapor Pressure at 25 ºC | 1 x 10E-6 | 2.1 x 10E-8 | 5 x 10E-10 |
Specific Gravity at 25 ºC | 1.07 | 1.07 | 1.09 |
Viscocity at 25 ºC | 45 | 39 | 175 |
Flash Point, open cup (ºC) | 193 | 221 | 243 |
Boiling point, 0.5 torr (ºC) | 180 | 215 | 245 |
Typical Boiler Temperature (ºC) | 190 | 220 | 260 |
Heat of Vaporization (kcal/gm mole) | 21.7/190 ºC | 25.5/200 ºC | 28.2/250 ºC |
Surface Tension (dynes) | 30 | 37.3 | 36.5 |
Molecular Weight | – | 484 | 546 |
Price per gallon | $375.00 | $475.00 | $595.00 |