Composition and method of making an element-modified ferrofluid

A magnetic fluid composition comprising:

• an oil-based, low vapor pressure carrier liquid;
• a plurality of magnetic particles coated with at least one surfactant, said plurality of magnetic particles dispersed within said carrier liquid forming a ferrofluid;
• and
• at least one elemental modifier disposed without dispersant within said ferrofluid wherein said elemental modifier is at least one of a metal, a metal mixture, a metal alloy, and a nonmetal, said at least one elemental modifier being present in said ferrofluid in an amount greater than zero percent and equal to or less than ten percent by weight to the weight of said ferrofluid and wherein said magnetic fluid is aged at room temperature or higher and at an elevated relative humidity for a sufficient time to provide said ferrofluid with a longer useful life than said ferrofluid would have without the addition of said at least one elemental modifier.

An element-modified magnetic fluid with a longer useful life obtained by the process comprising:

• adding a quantity of elemental modifier without dispersant to an oil-based, low vapor pressure magnetic fluid forming a mixture;
• aging said mixture at room temperature or higher and at an elevated relative humidity for a sufficient time to provide a ferrofluid with a longer useful life than said ferrofluid would have without the addition of said quantity of elemental modifier;
• and
• removing an excess of said elemental modifier from said magnetic fluid.

A method of making an improved magnetic fluid, said method comprising:

• obtaining a quantity of an oil-based, low vapor pressure magnetic fluid;
• adding an amount of elemental modifier without dispersant to said quantity of magnetic fluid;
• mixing said elemental modifier and said quantity of magnetic fluid forming a mixture;
• aging said mixture at room temperature or higher and at an elevated relative humidity for a sufficient time to provide said magnetic fluid with a longer useful life than said magnetic fluid would have without the addition of said amount of elemental modifier;
• and
• removing excess elemental modifier from said mixture.

A magnetic fluid composition comprising:

• an oil-based, low vapor pressure carrier liquid;
• a plurality of magnetic particles coated with at least one surfactant, said plurality of magnetic particles dispersed within said carrier liquid forming a ferrofluid;
• and
• at least one elemental modifier selected from the group consisting of a metal, a metal mixture, a metal alloy, and a nonmetal, wherein said metal, metal mixture, metal alloy and nonmetal is one or more of nickel, aluminum, silicon, titanium, vanadium, chromium, manganese, iron, cobalt, copper, zinc, silver, platinum, gold, boron, dysprosium, erbium, gadolinium, germanium, holmium, indium, iridium, palladium, lead, molybdenum, neodymium, niobium, osmium, rhodium, samarium, tantalum, tin, tungsten, yttrium, zirconium, ytterbium, thulium, terbium, praseodymium, bronze, cupra nickel, nickel chromium, nickel silver, palladium silver, zirconium nickel, titanium nickel, brass, a mix of chromium, nickel, manganese, silicon, and iron, and a mix of chromium, nickel, manganese, silicon, molybdenum, and iron;
• said at least one elemental modifier being disposed within said ferrofluid forming a treated ferrofluid wherein said at least one elemental modifier being present in said ferrofluid in an amount greater than zero percent and equal to or less than ten percent by weight to the weight of said ferrofluid and wherein said treated ferrofluid is aged at room temperature or higher and at an elevated relative humidity for a sufficient time to provide said ferrofluid with a longer useful life than said ferrofluid would have without the addition of said at least one elemental modifier.