NPI-14, NPI-16 & NPI-425
This lubricant contains MoS2 and graphite as the lubricating pigments, and phenolic resin as the binder system. The MoS2 to graphite ratio and the ratio of lubricating pigments to resin is representative of what was classed as a “good” lubricant in the series of round-robin tests conducted in the late 1960s to establish a technique for measuring wear life of bonded solid lubricant coatings using the Falex Pin and Vee Groove tester. This technique was subsequently released as ASTM specification D2625-69 and is the technique specified in military specifications MIL-L-8937 and MIL-L-46010. The nominal thickness of this lubricant is 0.0002 to 0.0005 inches and it is cured for 1 hour at +300°F. Although this lubricant is representative of the first bonded lubricants to be used, it is still the type approved by a number of companies for many applications which is the reason that NPI continues to offer NPI-14 to our customers.
This lubricant is essentially identical to the NPI-14 lubricant except the graphite has been replaced with other non-corrosion pigments. The nominal thickness and cure temperature are identical to NPI-14. It is intended for applications to surfaces that will be subjected to mechanical wear. The purpose of this product in it’s finished form is to reduce friction or prevent galling and seizure and to remain stable over it’s designed temperature range of -65°F to +300°F. Because it contains no graphite or powered metals it will not promote corrosion or have a deleterious effect on adjacent structures. NPI-16 is intended to meet the requirements of MIL-L-46010 Type I.
Wear Life Testing is routinely conducted using the Falex Pin and V-Block tester per ASTM D2625-69 Procedure A., material being used as noted:
Pins SAE 3135 Steel, V-Blocks AISIC 1137 Steel, Average wear life is 5.5 hours.
This lubricant contains MoS2, and other lubricating pigments in a polymide high temperature resin and was developed by Midwest Research Institute, Kansas City, Missouri in connection with a contract with the NASA Marshall Space Flight Center, Huntsville, Alabama. NPI has been licensed by MRI to formulate, apply and market this lubricant since 1968. This lubricant was developed for use at temperatures up to +500°F and in hard vacuum environments. NPI-425 has excellent wear life, having 3 to 5 times longer wear life than MIL-L-8937 lubricants at room temperature and 5 to 10 times longer at 450 F. It passes ASTM E595 outgassing requirements and is radiation resistant. The nominal thickness of this lubricant is 0.0002 to 0.0004 inches and is cured for 1 hour at +300°F followed by 1 hour at +575°F and, therefore, would not be considered suitable for use on some metallic substrates such as aluminum. Tests have shown, however, that acceptable performance can be obtained by increasing the +300°F cure time to 5 hours and eliminating the +575°F cure procedure. Tests also show that this lubricant has a very constant and low coefficient of friction compared to other lubricants.
Wear life testing is routinely conducted using the Falex Pin and V-Block tester, per ASTM D2625-69 Procedure A. Base material: V-Blocks AISIC 1137 Steel, Pins SAE 3135 Steel; average wear life is 7.65 hours. Load Carrying Capacity tests have also been run per ASTM D2625-69 Procedure B with test pieces reaching the 4500 lb load, and continuing to run for approximately twenty five minutes before failure. More information about the Falex Pin and V-Block tester can be found in the Wear Life Testing information area under NPI-1220.
NOTE: Safety data sheets for NPI-14, NPI-16 and NPI-425 are available upon request.AISIC