Iron particle passivation

Abstract

The invention relates to iron particle passivation. The present disclosure provides a coated iron particle, or a reaction product thereof, comprising an iron particle and a thiol coating disposed on the iron particle. The present disclosure also provides compositions comprising coated iron particles and a polymer or adhesion promoter. The present disclosure also provides an assembly having a surface and a composition of the present disclosure disposed on the surface. A method of passivating iron particles may include introducing a passivating agent having one or more sulfur moieties into a solvent to form a passivating solution; and contacting the iron particles with a passivation solution to form coated iron particles. A method of passivating iron particles may include introducing iron particles into a solvent to form an iron particle solution; and contacting a passivating agent having one or more sulfur moieties with the solution of iron particles to form coated iron particles.

Description

[0001] This application is a divisional application. The original application was filed on October 11, 2018, with application number 2018111815451 and invention title "Iron Particle Passivation". Technical Field

[0002] This disclosure provides thiol-coated iron particles, compositions comprising thiol-coated iron particles, components on which the compositions are placed, and methods for passivating iron particles. Background Technology

[0003] In recent years, magnetic particles, especially iron particles, have received significant attention due to their excellent magnetic properties and widespread application. They can be used in various technological fields, including biomedical applications, absorption and catalysis processes, and the production of magnetorheological fluids and composite materials. Depending on the required size, iron particles can be nanoscale, microscale, or macroscale.

[0004] For example, carbonyl iron particles are a key component used in the design of magnetic electromagnetic wave absorbers. Carbonyl iron is essentially pure iron (99.9% iron content or higher) formed from iron-containing carbonyl groups (e.g., Fe(CO)5). For instance, carbonyl iron powder (CIP) possesses specific magnetic properties, making it suitable for many applications and an ideal additive for coatings due to these magnetic properties. However, carbonyl iron is prone to oxidation and corrosion at high temperatures, leading to a decrease in magnetic properties. Furthermore, achieving uniform dispersion of CIP is challenging, and inadequate dispersion can negatively impact CIP performance. For example, methods such as coating particles with polymers can cause particle agglomeration and hinder particle dispersion.

[0005] For example, ferric silicate has been used instead of ferric carbonyl because it is less prone to corrosion and easier to process. Known passivation techniques for ferric carbonyl or ferric silicate include: carbon dioxide passivation, cobalt chemical plating, polyaniline passivation, microwave plasma processing, and silica coating. These methods involve many / complex processing steps, resulting in a significant increase in particle mass and volume, leading to particle aggregation and potentially reducing particle magnetism.

[0006] There is a need for passivated iron particles that retain or enhance magnetism, as well as methods for improving passivated iron particles. Summary of the Invention

[0007] This disclosure provides coated iron particles or their reaction products, comprising iron particles and a thiol coating placed on the iron particles.

[0008] This disclosure also provides compositions comprising coated iron particles and polymers or adhesion promoters.

[0009] This disclosure also provides components, such as vehicle components, which include a surface and a composition of this disclosure placed on the surface.

[0010] This disclosure also provides a method for passivating iron particles by introducing a passivating agent having one or more sulfur moieties into a solvent to form a passivation solution; and contacting the iron particles with the passivation solution to form coated iron particles.

[0011] This disclosure further provides a method for passivating iron particles by introducing iron particles into a solvent to form an iron particle solution; and contacting a passivating agent having one or more sulfur moieties with the iron particle solution to form coated iron particles. Attached Figure Description

[0012] To gain a more detailed understanding of the foregoing features of this disclosure, a more specific description of the disclosure, which has been briefly outlined above, can be made by referring to some of the aspects illustrated in the accompanying drawings. However, it should be noted that the drawings illustrate only typical aspects of this disclosure and should not be construed as limiting its scope, as other equally effective aspects are permissible.

[0013] Figure 1 It is an aircraft including vehicle components according to at least one aspect of this disclosure.

[0014] Figure 2 This is a flowchart of a method for forming thiol-coated iron particles according to at least one aspect of this disclosure.

[0015] Figure 3A The image is a scanning electron microscope image of carbonyl iron particles that have not been passivated with thiol, according to at least one aspect of this disclosure.

[0016] Figure 3B The image is a scanning electron microscope image of carbonyl iron particles that have not been passivated with thiol, according to at least one aspect of this disclosure.

[0017] Figure 3C The image is a scanning electron microscope image of carbonyl iron particles that have not been passivated with thiol, according to at least one aspect of this disclosure.

[0018] Figure 4A This is a scanning electron microscope image of carbonyl iron particles passivated with 2,5-dimercapto-1,3,4-thiadiazole according to at least one aspect of this disclosure.

[0019] Figure 4B This is a scanning electron microscope image of carbonyl iron particles passivated with 2,5-dimercapto-1,3,4-thiadiazole according to at least one aspect of this disclosure.

[0020] Figure 4CThis is a scanning electron microscope image of carbonyl iron particles passivated with 2,5-dimercapto-1,3,4-thiadiazole according to at least one aspect of this disclosure.

[0021] Figure 5A It is based on at least one aspect of this disclosure Figures 3A-3C Energy dispersive spectra of carbonyl iron particles in SEM images.

[0022] Figure 5B It is based on at least one aspect of this disclosure Figures 4A-4C Energy dispersive spectra of SEM images of 2,5-dimercapto-1,3,4-thiadiazole passivated iron particles.

[0023] Figure 6A This is a photograph of a panel coated with a polyurethane coating containing unmodified carbonyl iron particles.

[0024] Figure 6B It is a photograph of a panel coated with a polyurethane coating containing iron particles coated with thiol.

[0025] For ease of understanding, the same reference numerals are used where possible to denote common elements in the figures. Elements and features of one aspect may be advantageously incorporated into other aspects without further description. Detailed Implementation

[0026] This disclosure relates to coated iron particles and compositions that provide iron particles that are resistant to corrosion after passivation and retain their magnetism. Compared to conventional iron coating methods, the method for forming coated iron particles disclosed herein offers a simple (e.g., three-step) process and relatively inexpensive materials, all of which reduce manufacturing time and costs.

[0027] Coated iron particles This disclosure provides iron particles with a thiol coating. The thiol coating may partially or completely coat the outer surface of the iron particles. The iron particles may be substantially pure iron. The iron particles may include carbonyl iron particles or iron silicate particles. In at least one aspect, the diameter of the coated iron particles is from about 0.5 micrometers to about 1,000 micrometers, for example from about 1 micrometer to about 100 micrometers, for example from about 1 micrometer to about 20 micrometers, for example from about 1 micrometer to about 5 micrometers, for example from about 1 micrometer to about 3 micrometers, for example from about 1.2 micrometers. It has been found that large particles (e.g., greater than 1,000 micrometers) are difficult to disperse and difficult to spray evenly due to their weight. Smaller particles are easier to disperse and easier to spray evenly. The iron particles of this disclosure may have an iron content of about 90 wt% or higher, for example about 95 wt% or higher, for example about 99 wt% or higher, for example about 99.9 wt% or higher. The iron particles are available from commercial sources, such as BASF of Ludwigshafen, Germany.

[0028] In at least one aspect, a thiol coating is applied to the iron particles and has a thickness of about 30 angstroms to about 15,000 angstroms, for example, about 100 angstroms to about 1,000 angstroms. In at least one aspect, the thiol coating content of the coated iron particles is about 0.01 vol% to about 30 vol%, for example, about 0.05 vol% to about 10 vol%, for example, about 0.1 vol% to about 1 vol%, for example, about 0.5 vol%, which is determined based on the total volume of the thiol-coated iron particles by the difference in weight and density of the particles before and after coating. In at least one aspect, the thiol coating content of the coated iron particles is about 0.5 wt% to about 30 wt%, for example, about 1 wt% to about 10 wt%, for example, about 2 wt% to about 5 wt%, for example, about 3 wt%, which is determined based on the total weight of the thiol-coated iron particles by the difference in weight of the particles before and after coating. As used herein, the “thiol coating content” of the iron particles is the volume or weight percentage of the thiol coating on the coated iron particles.

[0029] The thiol coating disclosed herein has no or negligible effect on the magnetic susceptibility of iron particles. In electromagnetism, magnetic susceptibility (denoted as Χ) is... s Magnetic susceptibility is a measure of a material's magnetic properties. It indicates whether a material is attracted or repelled by a magnetic field, which can affect practical applications. As particle size increases (for pure iron), Χ... s Increase. In the coating, as the volume fraction increases, Χ s Increase. Therefore, if it is a core-shell structure (the core is iron, and the shell is a passivation layer), as the shell thickens, Χ s It will decrease. Furthermore, if particle corrosion occurs, the core size decreases and X... s This will reduce the corrosion caused by iron particles. The thiol coating disclosed herein prevents or reduces corrosion.

[0030] In at least one aspect, the coated iron particles of this disclosure have a diameter of about 1 micrometer to about 5 micrometers and have a density of about 3 x 10⁻⁶. s Approximately 10 Χ s The magnetic susceptibility. In at least one aspect, the X-ray susceptibility of the coated iron particles of this disclosure. s The ratio of particle diameter to particle size is from about 0.5:1 to about 1.5:1, for example, from about 0.7:1 to about 1.2:1, for example, about 1:1. s The ratio to particle diameter indicates that the thiol coating of this disclosure has no or negligible effect on the magnetic susceptibility of the iron particles, which provides the coated particles with good dispersion. The coated iron particles and composition of this disclosure are equally well dispersed (e.g., do not agglomerate) compared to unpassivated iron particles, unlike conventional coated iron particles, such as silica-coated iron particles.

[0031] In addition to promoting the dispersion of the coated particles in a composition with other iron particles (e.g., other coated iron particles), the thiol coating also provides corrosion resistance to the iron particles. Furthermore, the thiol coating of this disclosure is thick enough to provide adequate protection against corrosion for the iron particles, yet thin enough that the magnetic properties of the iron particles are not substantially reduced (if any). The thiol coating of this disclosure can be a self-assembled passivation monolayer on the surface of the iron particles. Without being bound by theory, the thiol compound (one or more) of the thiol coating can be covalently bonded to the surface of the iron particles.

[0032] The thiol coating disclosed herein may include one or more thiol compounds and / or their reaction products. In at least one aspect, the thiol compound is selected from heterocyclic thiols, disulfide compounds, thiolate compounds, and alkyl polythiols.

[0033] The thiol compounds disclosed herein can be organic compounds comprising disulfide groups and / or thiolate groups (e.g., metal-sulfide bonds). The thiol compounds can be alkyl polythiols, such as dithiols, trithiols, or tetrathiols. Compared to monothiols, polythiols can provide additional thiol moieties capable of interacting / covalently bonding with iron particles, providing a thiol coating on the iron particles that can have reduced thickness, increased overall bonding force with the iron particles, and maintain / improve the magnetism of the coated iron particles. Dithiols can include ethylenedithiol, propylenedithiol, butyldithiol, pentanedithiol, hexanedithiol, pentanedithiol, octanedithiol, nonanedithiol, and decandithiol. Trithiols can include ethylenetrithiol, propylenetrithiol, butyltrithiol, pentanedithiol, hexanedithiol, pentanedithiol, octanedithiol, nonanedithiol, and decandithiol. Tetrathiols can include ethylene tetrathiols, propylene tetrathiols, butyl tetrathiols, pentaerythiol, hexane tetrathiols, pentaerythiol, octane tetrathiols, nonane tetrathiols, and decantetrathiols.

[0034] In at least one respect, thiols are represented by the following formula: R 1 -S n -XR 2 , where R 1 It is an organic group, n is an integer greater than or equal to 1, X is a sulfur or metal atom, and R 2 It is an organic group. R 1 and R 2 One or both may include additional polysulfide groups and / or thiol groups. Furthermore, in at least one aspect, the thiol compound comprises having the formula –(R 1 -S n -XR 2 ) q – polymers, where R 1 It is an organic group, n is a positive integer, X is a sulfur or metal atom, and R 2It is an organic group, and q is a positive integer. In at least one aspect, R (of the polymerization or monomer corrosion inhibitor) 1 and R 2 It is independently selected from H, alkyl, cycloalkyl, aryl, thiol, polysulfide, or thion. R 1 and R 2 Each of these can be independently substituted by a moiety selected from alkyl, amino, phosphorus-containing groups, ethers, alkoxy, hydroxyl, sulfur-containing groups, selenium, or tellurium. In at least one aspect, R 1 and R 2 Each of them has 1-24 carbon atoms and / or non-hydrogen atoms. For example, R 1 and R 2 Examples of heterocyclic groups include azoles, triazoles, thiazoles, dithiazoles, and / or thiadiazoles.

[0035] In at least one aspect, the thiol compound comprises a metal in a metal-thiol salt complex. The thiol compound may include a metal center and one or more thiol groups (ligands) bonded to and / or coordinated with the metal center via metal-sulfide bonds. The thiol salt is a derivative of a thiol, wherein the metal atom replaces a hydrogen atom bonded to sulfur. The thiol salt has the general formula MSR. 1 Where M is a metal and R is a metal. 1 It is an organic group. R 1 It may include disulfide groups. Metal-thiolate complexes have the general formula M-(SR) 1 ) n , where n is usually an integer from 2 to 9, and M is a metal atom. The metals are copper, zinc, zirconium, aluminum, iron, cadmium, lead, mercury, silver, platinum, palladium, gold, and / or cobalt.

[0036] In at least one aspect, thiol compounds include azoles. Suitable examples of azoles include cyclic compounds having one nitrogen atom, such as pyrrole; compounds with two or more nitrogen atoms, such as pyrazoles, imidazoles, triazoles, tetraazoles, and pentaazoles; and compounds with one nitrogen atom and one oxygen atom, such as... azole and isosorbide The azole, along with one nitrogen atom and one sulfur atom, is such as thiazole and isothiazole. Non-limiting examples of suitable azole-containing thiols include 2,5-dimercapto-1,3,4-thiadiazole, 1H-benzotriazole, 1H-1,2,3-triazole, 2-amino-5-mercapto-1,3,4-thiadiazole, also known as 5-amino-1,3,4-thiadiazole-2-thiol, 2-amino-1,3,4-thiadiazole. In at least one aspect, for example, the azole can be 2,5-dimercapto-1,3,4-thiadiazole. In some embodiments, the azole-containing thiols include benzotriazole and / or 2,5-dimercapto-1,3,4-thiadiazole.

[0037] The thiol compounds disclosed herein include heterocyclic thiols and amines, which can provide oxygen-reducing elimination. Heterocyclic thiols include thiadiazoles having one or more thiol moieties. Non-limiting examples of thiadiazoles having one or more thiol moieties include 1,3,4-thiadiazole-2,5-dithiol and thiadiazoles represented by formula (I) or formula (II): Thiadiazole of formula (I) is available from Vanderbilt Chemicals, LLC (Norwalk, Connecticut) and is marketed as Vanlube® 829. Thiadiazole of formula (II) is available from WPC Technologies, Inc. TM (Oak Creek, Wisconsin) and is known as InhibiCor TM 1000.

[0038] The thiols disclosed herein can be derivatives of 2,5-dimercapto-1,3,4-thiadiazole, represented by HS-CN2SC-SH or “DMTD”, and selected derivatives of trithiocyanuric acid (“TMT”), which can be used as corrosion inhibitors in coating-related applications. Examples include 2,5-dimercapto-1,3,4-thiadiazole (DMTD) and 2,4-dimercapto-s-triazolo-[4,3-b]-1,3,4-thiadiazole, and trithiocyanuric acid (TMT). Other examples include N-,S- and N,N-, S,S- and N,S-substituted derivatives of DMTD, such as 5-mercapto-3-phenyl-1,3,4-thiadiazolin-2-thione or bismuth thiol II (3-phenyl-1,3,4-thiadiazolidine-2,5-dithione) and various S-substituted trithiocyanuric acid derivatives. Other examples include 5,5'-dithio-di(1,3,4-thiadiazole-2(3H)-thione) or (DMTD)2, or DMTD, polymers of DMTD; 5,5'-dithio-di(1,3,4-thiadiazole-2(3H)-thione); or (TMT)2, dimers and polymers of TMT. Other examples include those with the general formula M(DMTD). nSalts of DMTD, where n = 1, 2, or 3, and M is a metal cation, such as M = Zn(II), Bi(III), Co(II), Ni(II), Cd(II), Pb(II), Ag(I), Sb(III), Sn(II), Fe(II), or Cu(II) (examples: ZnDMTD, Zn(DMTD)2, Bi(DMTD)3); similar salts of TMT, such as ZnTMT, in a 1:1 ratio; and equivalent soluble Li(I), Ca(II), Sr(II), Mg(II), La(III), Ce(III), Pr(III), or Zr(IV) salts. Other examples include salts of the general formula M[(DMTD)]. n ] m (DMTD) n A salt in which n=2 or n>2, m=1, 2 or 3, and M is a metal cation, such as M=Zn(II), Bi(III), Co(II), Ni(II), Cd(II), Pb(II), Ag(I), Sb(III), Sn(II), Fe(II) or Cu(II). Typical examples are: Zn[(DMTD)2], Zn[(DMTD)2]2.

[0039] Other examples include DMTD, (DMTD) n Ammonium, aryl, or alkyl-ammonium salts of 5,5'-thio-bis(1,3,4-thiadiazole-2(3H)-thione) or 2,4-dimercapto-s-triazolo-[4,3-b]-1,3,4-thiadiazole. Typical examples include: cyclohexylamine:DMTD in ratios of 1:1 and 2:1; dicyclohexylamine:DMTD in ratios of 1:1 and 2:1; aniline:DMTD in ratios of 1:1 and 2:1; and similar salts of TMT, such as dicyclohexylamine:TMT in a ratio of 1:1. Other examples include DMTD or (DMTD) formed with polyamines. n And TMT's polyammonium salts.

[0040] Other examples include using DMTD or (DMTD) n Alternatively, intrinsically conductive polyaniline doped with 5,5'-thio-bis(1,3,4-thiadiazole-2(3H)-thione) and TMT; using DMTD or (DMTD) n Or 5,5'-thio-bis(1,3,4-thiadiazole-2(3H)-thione) and / or TMT-doped intrinsically conductive polypyrrole and / or polythiophene.

[0041] Other examples include micron- or nanocomposites of polyDMTD / polyaniline, polyDMTD / polypyrrole, and polyDMTD / polythiophene; similar micron- or nanocomposites with TMT; and similar micron- or nanocomposites with 5,5'-thio-di(1,3,4-thiadiazole-2(3H)-thione); DMTD or salts of DMTD or derivatives of DMTD and TMT, which serve as organic components of various pigment-grade inorganic matrices or physical mixtures. In some aspects, such inorganic matrices include anionic and cationic substances with corrosion-inhibiting properties, such as MoO4. - PO4 - HPO3 - Polyphosphate, BO2 - SiO4 - NCN - WO4 - Phosphomolybdate, phosphotungstic acid, and respectively Mg, Ca, Sr, La, Ce, Zn, Fe, Al, Bi.

[0042] DMTD pigment-grade forms include Zn(DMTD)2 and Zn-DMTD (as well as other organic and inorganic salts of the former), and its inorganic products or corrosion inhibitor pigments, including: phosphates, molybdates, borates, silicates, tungstates, phosphotungstates, phosphomolybdates, cyanamides, or carbonates of the aforementioned cationic substances, as well as oxides. Examples include: zinc phosphate, cerium molybdate, calcium silicate, strontium borate, zinc cyanamide, cerium phosphotungstate, ZnO, CeO2, ZrO2, and amorphous SiO2.

[0043] Composition and coating components The thiol-coated iron particles of this disclosure may be present in the composition. In at least one aspect, the composition of this disclosure comprises thiol-coated iron particles and one or more polymers or adhesion promoters. In at least one aspect, the polymer comprises at least one of thermosetting polymers or thermoplastic polymers. In at least one aspect, the polymer is at least one of epoxy resin, bismaleimide, polyimide, polyaryletherketone (e.g., polyetheretherketone or polyetherketone), sol-gel, polyurethane, sealant, or magnetorheological particle fluid. The adhesion promoter may be a sol-gel. The sol-gel may be Boegel®, such as 3M Surface Pretreatment AC-131 CB. 3% AC-131 kits are available from 3M. 3% AC-131 is a non-chromate conversion coating and is typically applied to aluminum, nickel, stainless steel, magnesium, and titanium alloys. AC-131 comprises part A, which is an aqueous mixture of glacial acetic acid (GAA) and tetra-n-propoxyzirconium (TPOZ), and part B, which is (3-glycidoxypropyl)trimethoxysilane (GTMS). The two components are mixed together (part A + part B) in a silicon to zirconium molar ratio of 2.77:1. Part A contains an acetic acid to TPOZ molar ratio of 0.45:1. A measured volume of GAA and TPOZ can be vigorously mixed for approximately 10 minutes and then added from the AC-131 kit to part A. The premixed part A solution can then be added to a measured volume of part B solution from the AC-131 kit and stirred, followed by an induction period of 30 minutes. The coated iron particles of this disclosure can be added to the part A / part B mixture before, during, or after the induction period. The composition can then be applied to a surface, such as the surface of a component, for example, a vehicle component.

[0044] Sealants include siloxanes, polyurethanes, and epoxy resins.

[0045] Magnetorheological particulate fluids include particles dispersed in hydrocarbon oils, silicone oils, aqueous phosphate fluids, and synthetic oils.

[0046] Synthetic oils include: Group I: Conventional non-synthetic oils. Made from fractionated distilled petroleum refined to improve certain performance categories such as wax content and antioxidant properties; Group II: Conventional non-synthetic oils. Made from fractionated distilled petroleum, which is further refined by hydrocracking (a hydrogen-based process); Group III: Considered synthetic oils, but arguably sharing some important similarities with conventional petroleum. Similar to Group II, but with a higher viscosity index due to further hydrocracking refinement; Group IV: Synthetic oils. Composed of polyalphaolefins (PAOs); Group V: This distinct group describes any base feedstock that does not conform to any of the first four groups.

[0047] The compositions disclosed herein may have a coated iron particle content of about 0.1 wt% to about 50 wt%, for example about 0.5 wt% to about 10 wt%, for example about 1 wt% to about 5 wt%, for example about 2 wt%. As used herein, the “iron particle content” of a composition is the weight percentage of the composition containing coated iron particles.

[0048] The compositions disclosed herein can be placed on a surface (e.g., the surface of a vehicle component). When placed on a component such as a vehicle component, the compositions disclosed herein provide a magnetic radar absorbing material capable of absorbing incident radio frequency radiation at frequencies from about 30 MHz to about 300 GHz, for example from about 300 MHz to about 30 MHz, for example from about 3,000 MHz to about 3 GHz.

[0049] The compositions disclosed herein can also be placed on one or more surfaces of a wind turbine, satellite, or other vehicle (e.g., a car, a ship, etc.).

[0050] Applying the composition to a surface can be done by spraying, dipping, brushing, and / or wiping to form a composition layer. Suitable spraying methods include application with a spray gun, a high-volume low-pressure spray gun, and / or a hand-operated pump sprayer. The solution is then cured (at room temperature or high temperature). In at least one aspect, the curing temperature is from about 10°C to about 150°C, for example from about 20°C to about 100°C, for example from about 30°C to about 70°C, for example from about 40°C to about 50°C. Curing can take place over a period of about 15 minutes to about 72 hours. The thickness of the cured composition layer of this disclosure can be from about 0.5 mils to about 500 mils, for example from about 5 mils to about 100 mils, for example from about 10 mils to about 50 mils.

[0051] Vehicle components are components of a vehicle, such as structural components of an aircraft, such as landing gear (one or more), panels, or joints. Examples of vehicle components include airfoils (e.g., rotor blades), auxiliary power units, aircraft nose cones, fuel tanks, tail cones, panels, coating overlap joints between two or more panels, wing-fuselage assemblies, structural aircraft composite materials, fuselage body joints, rib-skin joints, and / or other internal components.

[0052] Figure 1 It is an aircraft comprising vehicle components according to at least one aspect of this disclosure. For example... Figure 1 As shown, the aircraft 100 includes an aircraft structure 102, which includes a vehicle assembly such as an elongated body 104, a wing 106 extending laterally from the body 104, and a tail 108 extending longitudinally from the body 104. The compositions of this disclosure can be disposed on one or more surfaces of these aircraft assemblies to form one or more aircraft assemblies (one or more) on which the compositions are disposed.

[0053] Other possible end uses of the coated iron particles and / or compositions disclosed herein may include incorporating the coated iron particles and / or compositions into or on magnetic tapes (e.g., storage media), electric motors (e.g., magnetic bearings), wind turbines (e.g., Doppler radar absorbers to absorb electromagnetic radiation), shielding nuclear magnetic resonance (NMR) spectrometers (e.g., magnetic coatings), lining anechoic chambers (as foam absorbers), generating magnetic field strength variations in mu metals, and acting as an "RF overlay" to protect computer chips from frequency exposure. The methods of this disclosure may also include passivating copper particles (e.g., any small, corroded metal particles) for use in products such as conductive inks.

[0054] Iron particle passivation This disclosure provides a method for forming thiol-coated iron particles by passivating iron particles with a passivating agent. Figure 2 This is a method 200 for forming thiol-coated iron particles. Method 200 includes forming a passivation solution by dissolving or dispersing a passivating agent having one or more sulfur moieties in a solvent (box 202).

[0055] The solvent can be aqueous or non-aqueous (e.g., organic). Preferably, the solvent is non-aqueous and contains little or no ammonium hydroxide. Non-aqueous solvents have been found to prevent iron particles from agglomerating in the presence of the passivation solution. In at least one aspect, the organic solvent is selected from alcohols, alkyl carbonates (e.g., dimethyl carbonate, diethyl carbonate, or dipropyl carbonate), ethers (e.g., dimethyl ether or dipropylene glycol dimethyl ether), glycol ethers, tetrahydrofuran (THF), N-methyl-2-pyrrolidone (NMP), dimethyl sulfoxide (DMSO), or mixtures thereof. In at least one aspect, the alcohol solvent is one or more of ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, and pentanol (e.g., n-pentanol, isopentanol, and sec-pentanol). Non-aqueous solvents can be degassed to remove air and moisture from the solvent by: (1) introducing a 3 Å or 4 Å molecular sieve into the solvent and heating the solvent and / or (2) bubbling an inert gas (such as nitrogen or argon) into the solvent for a period of about 10 minutes to about 24 hours.

[0056] In at least one aspect, the concentration (in moles per liter) of the passivating agent in the passivation solution is from about 0.01 mol / L (M) to about 10 M, for example from about 0.5 M to about 5 M, for example from about 1 M to about 2 M.

[0057] In at least one aspect, the passivating agent is a thiol compound. In at least one aspect, the passivating agent is selected from heterocyclic thiols, disulfide compounds, thiolate compounds, and alkyl polythiols.

[0058] The thiol compounds disclosed herein can be organic compounds comprising a disulfide group and / or a thiolate group (e.g., a metal-sulfide bond). The thiol compounds can be alkyl polythiols, such as dithiols, trithiols, or tetrathiols. Dithiols may include ethylenedithiol, propylenedithiol, butyldithiol, pentanedithiol, hexanedithiol, pentanedithiol, octanedithiol, nonanedithiol, and decandithiol. Trithiols may include ethylenetrithiol, propylenetrithiol, butyltrithiol, pentanedithiol, hexanedithiol, pentanedithiol, octanedithiol, nonanedithiol, and decandithiol. Tetrathiols may include ethylenetetrathiol, propylenetetrathiol, butyltetrathiol, pentanedithiol, hexanedithiol, pentanedithiol, octanedithiol, nonanedithiol, and decandithiol.

[0059] In at least one respect, thiols are represented by the following formula: R 1 -S n -XR 2 , where R 1 It is an organic group, n is an integer greater than or equal to 1, X is a sulfur or metal atom, and R 2 It is an organic group. R 1 and R 2 One or both may include additional polysulfide groups and / or thiol groups. Furthermore, in at least one aspect, the thiol compound comprises having the formula –(R 1 -S n -XR 2 ) q – polymers, where R 1 It is an organic group, n is a positive integer, X is a sulfur or metal atom, and R 2 It is an organic group, and q is a positive integer. In at least one aspect, R (polymerization or monomer corrosion inhibitor) 1 and R 2 It is independently selected from H, alkyl, cycloalkyl, aryl, thiol, polysulfide, or thion. R 1 and R 2 Each of these can be independently substituted by a moiety selected from alkyl, amino, phosphorus-containing groups, ethers, alkoxy, hydroxyl, sulfur-containing groups, selenium, or tellurium. In at least one aspect, R 1 and R 2 Each of them has 1-24 carbon atoms and / or non-hydrogen atoms. For example, R 1 and R 2 Examples of heterocyclic groups include azoles, triazoles, thiazoles, dithiazoles, and / or thiadiazoles.

[0060] In at least one aspect, the thiol compound comprises a metal in a metal-thiol salt complex. The thiol compound may include a metal center and one or more thiol groups (ligands) bonded and / or coordinated to the metal center via metal-sulfide bonds. The thiol salt is a derivative of a thiol in which a metal atom replaces a hydrogen atom bonded to sulfur. The thiol salt has the general formula MSR. 1 Where M is a metal and R is a metal. 1 It is an organic group. R 1 It may include disulfide groups. Metal-thiolate complexes have the general formula M-(S-R) 1 ) n , where n is usually an integer from 2 to 9, and M is a metal atom. The metals are copper, zinc, zirconium, aluminum, iron, cadmium, lead, mercury, silver, platinum, palladium, gold, and / or cobalt.

[0061] In at least one aspect, thiol compounds include azoles. Suitable examples of azoles include cyclic compounds having one nitrogen atom, such as pyrrole; compounds with two or more nitrogen atoms, such as pyrazoles, imidazoles, triazoles, tetraazoles, and pentaazoles; and compounds with one nitrogen atom and one oxygen atom, such as... azole and isosorbide The azole, and one nitrogen atom and one sulfur atom, such as thiazole and isothiazole. Non-limiting examples of suitable azole-containing thiols include 2,5-dimercapto-1,3,4-thiadiazole, 1H-benzotriazole, 1H-1,2,3-triazole, 2-amino-5-mercapto-1,3,4-thiadiazole, also known as 5-amino-1,3,4-thiadiazole-2-thiol, 2-amino-1,3,4-thiadiazole. In at least one aspect, for example, the azole can be 2,5-dimercapto-1,3,4-thiadiazole. In some embodiments, the azole-containing thiols include benzotriazole and / or 2,5-dimercapto-1,3,4-thiadiazole.

[0062] The thiol compounds disclosed herein include heterocyclic thiols and amines, which can provide oxygen-reducing elimination. Heterocyclic thiols include thiadiazoles having one or more thiol moieties. Non-limiting examples of thiadiazoles having one or more thiol moieties include 1,3,4-thiadiazole-2,5-dithiol and thiadiazoles represented by formula (I) or formula (II): Thiadiazole of formula (I) is available from Vanderbilt Chemicals, LLC (Norwalk, Connecticut) and is marketed as Vanlube® 829. Thiadiazole of formula (II) is available from WPC Technologies, Inc. TM (Oak Creek, Wisconsin) and is known as InhibiCor TM 1000.

[0063] The thiol compounds disclosed herein can be derivatives of 2,5-dimercapto-1,3,4-thiadiazole, represented by HS-CN2SC-SH or “DMTD”, and selected derivatives of trithiocyanuric acid (“TMT”), which can be used as corrosion inhibitors in coating-related applications. Examples include 2,5-dimercapto-1,3,4-thiadiazole (DMTD) and 2,4-dimercapto-s-triazolo-[4,3-b]-1,3,4-thiadiazole and trithiocyanuric acid (TMT). Other examples include N-, S-, and N,N-, S,S-, and N,S-substituted derivatives of DMTD, such as 5-mercapto-3-phenyl-1,3,4-thiadiazolin-2-thione or bismuth thiol II (3-phenyl-1,3,4-thiadiazolidine-2,5-dithione) and various S-substituted trithiocyanuric acid derivatives. Other examples include polymers of 5,5'-dithio-di(1,3,4-thiadiazole-2(3H)-thione) or (DMTD)2, or (DMTD), DMTD; 5,5'-dithio-di(1,3,4-thiadiazole-2(3H)-thione); or (TMT)2, TMT dimers and polymers. Other examples include those with the general formula M(DMTD). n Salts of DMTD, where n = 1, 2, or 3, and M is a metal cation, such as M = Zn(II), Bi(III), Co(II), Ni(II), Cd(II), Pb(II), Ag(I), Sb(III), Sn(II), Fe(II), or Cu(II) (examples: ZnDMTD, Zn(DMTD)2, Bi(DMTD)3); similar salts of TMT, such as ZnTMT, in a 1:1 ratio; and equivalent soluble Li(I), Ca(II), Sr(II), Mg(II), La(III), Ce(III), Pr(III), or Zr(IV) salts. Other examples include salts of the general formula M[(DMTD)]. n ] m (DMTD) n A salt in which n=2 or n>2, m=1, 2 or 3, and M is a metal cation, such as M=Zn(II), Bi(III), Co(II), Ni(II), Cd(II), Pb(II), Ag(I), Sb(III), Sn(II), Fe(II) or Cu(II). Typical examples are: Zn[(DMTD)2], Zn[(DMTD)2]2.

[0064] Other examples include DMTD, (DMTD) nAmmonium, aryl, or alkyl-ammonium salts of 5,5'-thio-bis(1,3,4-thiadiazole-2(3H)-thione) or 2,4-dimercapto-s-triazolo-[4,3-b]-1,3,4-thiadiazole. Typical examples include: cyclohexylamine:DMTD in ratios of 1:1 and 2:1; dicyclohexylamine:DMTD in ratios of 1:1 and 2:1; aniline:DMTD in ratios of 1:1 and 2:1; and similar salts of TMT, such as dicyclohexylamine:TMT in a ratio of 1:1. Other examples include DMTD or (DMTD) formed with polyamines. n And TMT's polyammonium salts.

[0065] Other examples include using DMTD or (DMTD) n Alternatively, intrinsically conductive polyaniline doped with 5,5'-thio-bis(1,3,4-thiadiazole-2(3H)-thione) and TMT; using DMTD or (DMTD) n Or 5,5'-thio-bis(1,3,4-thiadiazole-2(3H)-thione) and / or TMT-doped intrinsically conductive polypyrrole and / or polythiophene.

[0066] Other examples include micron- or nanocomposites of polyDMTD / polyaniline, polyDMTD / polypyrrole, and polyDMTD / polythiophene; similar micron- or nanocomposites with TMT; and similar micron- or nanocomposites with 5,5'-thio-di(1,3,4-thiadiazole-2(3H)-thione); DMTD or salts of DMTD or derivatives of DMTD and TMT, which serve as organic components of various pigment-grade inorganic matrices or physical mixtures. In some aspects, such inorganic matrices include anionic and cationic substances with corrosion-inhibiting properties, such as MoO4. - PO4 - HPO3 - Polyphosphate, BO2 - SiO4 - NCN - WO4 - Phosphomolybdate, phosphotungstic acid, and respectively Mg, Ca, Sr, La, Ce, Zn, Fe, Al, Bi.

[0067] Other examples include DMTD or DMTD salts or DMTD and TMT derivatives in capsule form, such as inclusions in various polymer matrices, or cyclodextrin inclusions or microcapsule forms.

[0068] DMTD pigment-grade forms include Zn(DMTD)2 and Zn-DMTD (as well as other organic and inorganic salts of the former), and its inorganic products or corrosion inhibitor pigments, including: phosphates, molybdates, borates, silicates, tungstates, phosphotungstates, phosphomolybdates, cyanamides, or carbonates of the aforementioned cationic substances, as well as oxides. Examples include: zinc phosphate, cerium molybdate, calcium silicate, strontium borate, zinc cyanamide, cerium phosphotungstate, ZnO, CeO2, ZrO2, and amorphous SiO2.

[0069] Method 200 includes introducing iron particles (e.g., carbonyl iron powder) into a passivation solution (block 204) to form fully or partially coated (e.g., encapsulated) iron particles in the passivating agent. Optionally, block 204 may include introducing the iron particles into a solvent to form an iron particle solution, and then introducing a passivating agent into the iron particle solution to form fully or partially coated (e.g., encapsulated) iron particles in the passivating agent. The introduction (block 204) may include gently mixing the iron particles in the passivation solution or the iron particle solution using any suitable stirring device, such as a stirring rod or impeller or a vortex mixer. Stirring may be performed in a roller mixer to provide a gentle mixing environment. It has been found that excessively vigorous mixing (or exposure to solutions of irritating chemicals, such as acidic solutions with a pH of approximately 3 or alkaline solutions with a pH of approximately 11 (e.g., ammonium hydroxide)) can oxidize the iron particles, reducing their magnetic properties. For example, mixing iron particles with concentrated 2,5-dimercapto-1,3,4-thiadiazole (DMcT) in a Thinky mixer can corrode the iron particles. Furthermore, some thiol compounds can be considered acidic and / or basic. For instance, DMcT is acidic, and iron particles exposed to a concentrated DMcT solution for too long can corrode them.

[0070] In at least one aspect, the weight ratio (g / g) of the passivating agent to the iron particles is from about 0.01:1 to about 1:0.01, for example from about 0.05:1 to about 0.5:1, for example from about 0.1:1 to about 0.4:1, for example from about 0.11:1.

[0071] Before and / or during the introduction of iron particles into the passivation solution, the passivation solution or the iron particle solution may be heated. In at least one aspect, the method includes heating the passivation solution to a temperature of about 20°C to about 120°C, for example, about 40°C to about 80°C, for example, about 60°C. In at least one aspect, the method includes heating the iron particle solution to a temperature of about 20°C to about 120°C, for example, about 40°C to about 80°C, for example, about 60°C.

[0072] In at least one aspect, stirring / mixing is performed at a stirring rate / vibration rate of about 50 revolutions per minute (rpm) to about 5,000 rpm, for example, about 300 rpm to about 2,000 rpm. In at least one aspect, the mixing takes place for a period of time from about 10 seconds to about 1 hour, for example, from about 30 seconds to about 5 minutes.

[0073] Method 200 includes removing coated iron particles from a passivation solution (block 206). Removal can be performed using any suitable filtration device, such as filter paper or a wire mesh filter. In at least one aspect, the method includes filtering the coated iron particles. The average pore size of the filter paper or wire mesh can be 100 micrometers or smaller, for example, from about 0.1 micrometers to about 50 micrometers, from about 3 micrometers to about 20 micrometers, or from about 11 micrometers (Grade 1). The filtration device can be pressurized or depressurized (e.g., under vacuum) to facilitate filtration of the coated iron particles as the filter media and the solvent as the filtrate. Method 200 also includes washing the filtered coated particles with a solvent (block 208). In at least one aspect, the solvent is one or more of an alcohol (e.g., isopropanol, ethanol, or methanol), an alkane (e.g., hexane), or an alkyl carbonate (e.g., dimethyl carbonate, diethyl carbonate, or dipropyl carbonate).

[0074] Method 200 includes drying the coated iron particles (box 210). Drying can be performed using filter cloth, towels, and / or pressurized air / inert gas. Inert gases include nitrogen and / or argon. Optionally or additionally, drying is performed by curing the coated iron particles at room temperature or elevated temperatures. In at least one aspect, the method includes drying the coated iron particles by curing them at temperatures ranging from about 10°C to about 150°C, for example from about 20°C to about 100°C, for example from about 30°C to about 70°C, for example from about 40°C to about 50°C. Curing can take place over a period of about 15 minutes to about 72 hours.

[0075] Example Example 1 : Material : 1. 2,5-Dimercapto-1,3,4-thiadiazole (DMcT) from Acros, molecular weight: 150.232 g / mol.

[0076] 2. Vanlube 829, 871 and 972 M from RT Vanderbilt.

[0077] 3. Carbonyl iron powder (CIP) HQ from BASF.

[0078] Roller mill sample preparation DMcT-CIP: Dissolve 3 g DMcT in 150.85 g degassed isopropanol (density 0.786 g / cm³). 3 In a mixture of 2.0 wt% and 0.104 M solutions, CIP dispersions were prepared in small glass vials as described in Table 1. All solutions were degassed with nitrogen. The vials were mixed for three days using a roller mill.

[0079] Table 1 Table 1: Continued After grinding, IPA was distilled from the vials using a rotary evaporator equipped with a special adapter to accommodate the vials. The corrosion resistance of the above samples to acetic acid at pH 2.9 and 5% NaCl was evaluated. A piece of filter paper was placed at the bottom of the vial, and a small amount of powdered sample was sprinkled onto the filter paper. A few drops of acidified NaCl solution were then added to the sample to saturate the filter paper. The vial was then sealed with a screw cap and allowed to react for 24 hours. It was observed that the highest DMCT / CIP ratio exhibited corrosion protection compared to other samples. Other examples and data using the Thinky Orbital mixer provided similar results.

[0080] Orbital mixer for preparing DMT-CIP 25.33 g of CIP was mixed with 140.38 g of 0.1 M DMcT in IPA and mixed using a Thinky mixer. As shown in Table 2, 11 to 15 g of sample was removed from the mixing container at different time intervals and placed in sealed vials.

[0081] Table 2 The samples were separated from the DMCPT IPA solution by vacuum filtration through a 0.2-micron Teflon filter and washed with IPA. The corrosion resistance of the samples to acetic acid at pH 2.8 in 5% NaCl was tested and compared with a control by impregnating a filter paper with the solution and spraying it onto CIP powder. The samples were placed in sealed containers and exposed for 24 hours; visual corrosion, i.e., the formation of red rust, was then compared between the samples.

[0082] VL829-CIP prepared by orbital mixer 5.96 g of Vanlube 829 (VL829) (molecular weight 298.48) was dispersed in 200 mL of 1 M ammonium hydroxide to obtain a 1.0 M solution. The solution was heated to boiling. After 10 minutes, the solution color changed from dark yellow to light yellow. The solution was passed through a 1-micron vacuum filter to remove any undissolved substances (if any, it was very small). 24.62 g of CIP was added to the VL829 ammonium hydroxide solution and mixed in a Thinky solution at 1100 rpm. Samples were taken at 29.5-minute intervals, as shown in Table 3. As can be seen from Table 1, the weight ratio of DMCT to CIP is 0.11.

[0083] Table 3 The collected samples were allowed to settle, and the supernatant was decanted. The wet powder was then vacuum-dried overnight at 60°C. The corrosion resistance of the samples to acetic acid at pH 2.8 in 5% NaCl was tested. Samples 1-3 showed some improvement in corrosion resistance.

[0084] Ultrasonic treatment methods for Vanlube 871 and 972M Vanlube 871 and 972M were also evaluated as coating formulations for CIP. Vanlube 972M is a thiadiazole derivative in polyalkylene glycols, while Vanlube 871 is a 2,5-dimercapto-1,3,4-thiadiazolealkylcarboxylic acid ester. In this case, both materials were dispersed together with CIP and isopropanol and subjected to ultrasonic treatment as described in Table 4.

[0085] Table 4 The coated CIP was recovered from the solution, air-dried, and its corrosion resistance was tested. VL972M showed better corrosion protection than VL871.

[0086] Track mixer fabrication IC 1000-CIP 7.2 g of Inhibitor 1000 from Wayne Pigments was mixed into 200 mL of 0.1 M ammonium hydroxide and boiled for 15 minutes. It was then placed in a roller mill and mixed over the entire weekend. After filtration, a white powder remained on the filter, while the filtrate was observed to be yellow. 10 g of CIP was mixed with 200 mL of the filtrate and mixed at 1100 rpm on a Thinky track mixer, with samples taken at 29.5 min, 59 min, and 88.5 min. The samples were filtered, rinsed with deionized water, and air-dried. Their corrosion resistance was then evaluated. The results showed that sample 2 (59 min sample) exhibited the best corrosion resistance. Further investigation suggested that the yellow filtrate was most likely DMcT, and the white powder was zinc oxide / zinc hydroxide. Essentially, this experiment most likely evaluated the role of DMcT in ammonium hydroxide.

[0087] Example 1 Observation : 1. DMcT-CIP was prepared from an IPA solution of DMcT using a roller mill and a rail Thinky mill.

[0088] 2. When DMcT-CIP prepared in IPA at a weight ratio of 0.11 using the orbital mixing method was exposed to an acidified salt solution, the corrosion resistance of the CIP iron particles was significantly improved.

[0089] 3. When prepared in ammonium hydroxide using the orbital mixing method, VL829-CIP exhibits edge corrosion protection properties.

[0090] 4. Using IPA as a diluent and employing ultrasonic treatment, VL972M exhibited better performance than VL 871, but slightly lower than DMCT.

[0091] 5. When using IPA as a solvent to coat particles with DMcT, the roller milling method shows to be superior to the Thinky method.

[0092] also, Figure 3A , 3B The images shown are scanning electron microscope images of carbonyl iron particles that have not been passivated with thiol. The particles are essentially spherical. Figure 4A , 4B Images 4C are scanning electron microscope images of carbonyl iron particles that have been passivated with DMcT. Many particles are rectangular in shape, while many others are spherical.

[0093] Furthermore, backscattered electron images in SEM reveal compositional contrasts resulting from elements of different atomic numbers and their distributions. Energy-dispersive spectroscopy (EDS) allows for the identification of specific elements and their relative proportions (e.g., atomic %). Figure 5A yes Figures 3A-3C EDS spectra of SEM images of carbonyl iron particles. (e.g.) Figure 5A As shown, these particles do not contain sulfur. Figure 5B yes Figures 4A-4C EDS spectra of SEM images of DMcT passivated iron particles. (e.g.) Figure 5B As shown, the particles contain a large amount of sulfur, indicating that a thiol passivation layer is placed on them.

[0094] Example 2 Additional testing of the coated particles was conducted under SO2 mist (ASTM B117), which has a low pH (3) and is considered a very intense test. No corrosion was observed, and the particle spheres exhibited magnetic susceptibility.

[0095] Example 3 The CIP particles were formulated with a polyurethane coating. This coating was tested for 500 hours on polycarbonate panels placed in a standard salt spray chamber. These panels showed no signs of corrosion. The coating did not interfere with the magnetism of the iron particles. A control sample was run, but it failed.

[0096] Materials for Example 3: 1. Modified and unmodified CIP powders 2. PPG polyurethane PR1664 Base (Part B) and 73008-001 (Part A); 10:1 weight ratio 3. Dimethyl carbonate (DMC) solvent 4. 3×5 polycarbonate (PC) sheet Example 3 Equipment: 1. Thinky mixer (sequential settings): 500 rpm for 30 seconds, 1,000 rpm for 30 seconds, 1,500 rpm for 30 seconds. 2. Disposable 200 mL polypropylene cup Example 3 Process (for modified and unmodified CIP): 1. Dissolve 50 g of part B in 60 g of DMC in a 200 mL disposable cup.

[0097] 2. Add 50 g of CIP to the above solution.

[0098] 3. Run Thinky according to the procedure above.

[0099] 4. Add 5 g of part A to the mixed dispersion.

[0100] 5. Run Thinky according to the above procedure.

[0101] 6. Transfer the contents to a spray bottle and dilute with DMC as needed to achieve a sprayable consistency.

[0102] 7. Spray onto 10 PC boards. Spray the formulation immediately after mixing.

[0103] 8. Allow the coated board to air dry for 24 hours.

[0104] Observation results of Example 3 : Figure 6A This is a photograph of a panel coated with a polyurethane coating containing unmodified carbonyl iron particles. The coated panel was exposed to salt spray for 1,000 hours according to ASTM B117. Figure 6A As shown, extensive corrosion was observed. Figure 6B This is a photograph of a panel coated with a polyurethane coating containing iron particles coated with thiol. The coated panel was exposed to salt spray for 1,000 hours according to ASTM B117. Figure 6B As shown, no corrosion was observed on the plate.

[0105] In summary, the coated iron particles and composition of this disclosure provide iron particles that are resistant to corrosion and retain their magnetism after passivation. Furthermore, unlike conventionally coated iron particles, the coated iron particles and composition of this disclosure exhibit equally good dispersion (e.g., no agglomeration) compared to unpassivated iron particles. Compared to conventional iron coating methods, the method of forming coated iron particles disclosed herein provides a simple (e.g., three-step) process using relatively inexpensive materials, all of which reduce manufacturing time and costs.

[0106] definition The term "alkyl" includes substituted or unsubstituted straight-chain or branched acyclic alkyl groups containing 1 to about 20 carbon atoms. In at least one aspect, an alkyl group includes a straight-chain or branched C14 group. 1-20 Alkyl group. C 1-20 Alkyl groups include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecanyl, octadecyl, nonadecanyl, eicosyl, and their structural isomers.

[0107] The term "cycloalkyl" includes substituted or unsubstituted cycloalkyl groups containing 1 to about 20 carbon atoms.

[0108] The term "aryl" refers to any monocyclic, bicyclic, or tricyclic carbocyclic ring having up to six atoms in each ring, wherein at least one ring is aromatic, or an aromatic ring system of 5 to 14 carbon atoms comprising a carbocyclic aromatic group fused to a 5- or 6-membered cycloalkyl group. Examples of aryl groups include, but are not limited to, phenyl, naphthyl, anthracene, or pyrene.

[0109] The term "alkoxy" is RO-, where R is an alkyl group as defined herein. The terms alkyloxy, alkoxyl, and alkoxy are used interchangeably. Examples of alkoxy groups include, but are not limited to, methoxy, ethoxy, propoxy, butoxy, pentoxy, hexoxy, heptoxy, octoxy, nonoxy, decoxy, and their structural isomers.

[0110] The term "ether" refers to an oxygen atom that bridges two carbon atoms.

[0111] The term "thion" refers to the part represented by the structure –CR2-(C=S)-CR2-, where each R is independently hydrogen, alkyl, acyl, heteroalkyl, aryl, cycloalkyl, heteroaryl, or heterocycloalkyl.

[0112] The term "heterocyclic group" refers to a monocyclic, bicyclic, or tricyclic ring having a maximum of 10 atoms in each ring, wherein at least one ring is aromatic and contains 1-4 heteroatoms selected from N, O, and S. Non-limiting examples of heterocyclic groups include pyridinyl, thiopheneyl, furanyl, pyrimidinyl, imidazoleyl, pyranyl, pyrazolyl, thiazolyl, thiadiazolyl, and isothiazolyl. azole group, iso Azolyl, pyrroleyl, pyridazinyl, pyrazinyl, quinolinyl, isoquinolinyl, benzofuranyl, dibenzofuranyl, dibenzothiophenyl, benzothiophenyl, indoleyl, benzothiazolyl, benzo[] Azolyl, benzimidazolyl, isoindolyl, benzotriazolyl, purine, thiamethoxymethyl, pyrazinyl, azole, triazole, thiazole, dithiazole, and thiadiazole. The linkage of heterocyclic groups can occur via an aromatic ring or via a non-aromatic ring or a ring without heteroatoms.

[0113] The term "amino" refers to a group containing a primary, secondary, or tertiary amine. An example of an amino group is -NH₂. Amino groups can be converted by R… 4 Or R 5 Replace (e.g.) ), where R 4 It can be, for example, cyano, haloacyl, alkenylcarbonyl, hydroxyalkenylcarbonyl, aminoalkenylcarbonyl, monoalkylaminoalkenylcarbonyl, dialkylaminoalkenylcarbonyl, haloalkenylcarbonyl, cyanoalkenylcarbonyl, alkoxycarbonylalkenylcarbonyl, alkynylcarbonyl, hydroxyalkynylcarbonyl, alkylcarbonylalkenylcarbonyl, cycloalkylcarbonylalkenylcarbonyl, arylcarbonylalkenylcarbonyl, aminocarbonylalkenylcarbonyl, monoalkylaminocarbonylalkenylcarbonyl, dialkylaminocarbonylalkenylcarbonyl, or alkenylsulfonyl; and R 5 It can be, for example, H, alkyl, or cycloalkyl.

[0114] The compounds disclosed herein include tautomers, geometric isomers, or stereoisomers of the compounds. This disclosure also includes compounds in the forms of esters, oximes, onions, hydrates, solvates, and N-oxides. This disclosure encompasses all such compounds, including cis and trans geometric isomers (Z- and E-geometric isomers), R- and S-enantiomers, diastereomers, d-isomers, l-isomers, blocked isomers, epimers, conformational isomers, rotational isomers, and mixtures of their isomers and racemates.

[0115] Various aspects of this disclosure have been described for illustrative purposes, but are not intended to be exhaustive or limiting. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the aspects described. The terminology used herein has been chosen to best explain the principles, practical applications, or improvements to technology found in the market, or to enable those skilled in the art to understand the aspects disclosed herein. While the foregoing addresses aspects of this disclosure, other and further aspects of this disclosure may arise without departing from its essential scope.

Claims

1. Coated iron particles or their reaction products, including: Iron particles with a diameter of approximately 0.5 micrometers to approximately 1,000 micrometers; and A thiol coating placed on the iron particles.

2. The coated iron particles of claim 1, wherein the diameter of the iron particles is from about 1 micrometer to about 1,000 micrometers.

3. The coated iron particles of claim 2, wherein the iron particles have an iron content of about 99 wt% or higher.

4. The coated iron particles of claim 1, wherein the thickness of the thiol coating is from about 10 angstroms to about 1,000 angstroms.

5. The coated iron particles of claim 4, wherein the coated iron particles have a thiol coating content of about 1 vol% to about 10 vol% based on the total volume of the thiol-coated iron particles, determined by the difference in weight and density of the particles before and after coating.

6. The coated iron particles of claim 4, wherein the coated iron particles have a thiol coating content of about 1 wt% to about 10 wt% based on the total weight of the thiol-coated iron particles, determined by the difference in weight of the particles before and after coating.

7. The coated iron particles of claim 6, wherein the coated iron particles have a thiol coating content of about 2 wt% to about 5 wt% based on the total weight of the thiol-coated iron particles, determined by the difference in weight of the particles before and after coating.

8. The coated iron particles of claim 1, wherein the ratio of Xs to particle diameter of the coated iron particles is about 0.5:1 to about 1.5:

1.

9. The coated iron particles of claim 1, wherein the thiol coating comprises a thiol compound selected from heterocyclic thiols, disulfides, thiols, and alkyl polythiols, or their reaction products.

10. The coated iron particles of claim 9, wherein the thiol coating comprises an alkyl polythiol selected from ethylenedithiol, propylenedithiol, butyldithiol, pentanedithiol, hexanedithiol, pentanedithiol, octanedithiol, nonanedithiol, and decandithiol, or a reaction product thereof.

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