CA2347824A1 - Surface-modified manganese sulfide, method for producing the same and use thereof - Google Patents
Surface-modified manganese sulfide, method for producing the same and use thereof Download PDFInfo
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- CA2347824A1 CA2347824A1 CA002347824A CA2347824A CA2347824A1 CA 2347824 A1 CA2347824 A1 CA 2347824A1 CA 002347824 A CA002347824 A CA 002347824A CA 2347824 A CA2347824 A CA 2347824A CA 2347824 A1 CA2347824 A1 CA 2347824A1
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09C—TREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS, TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES ; PREPARATION OF CARBON BLACK ; PREPARATION OF INORGANIC MATERIALS WHICH ARE NO SINGLE CHEMICAL COMPOUNDS AND WHICH ARE MAINLY USED AS PIGMENTS OR FILLERS
- C09C1/00—Treatment of specific inorganic materials other than fibrous fillers; Preparation of carbon black
- C09C1/0009—Pigments for ceramics
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09C—TREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS, TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES ; PREPARATION OF CARBON BLACK ; PREPARATION OF INORGANIC MATERIALS WHICH ARE NO SINGLE CHEMICAL COMPOUNDS AND WHICH ARE MAINLY USED AS PIGMENTS OR FILLERS
- C09C3/00—Treatment in general of inorganic materials, other than fibrous fillers, to enhance their pigmenting or filling properties
- C09C3/08—Treatment with low-molecular-weight non-polymer organic compounds
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09C—TREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS, TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES ; PREPARATION OF CARBON BLACK ; PREPARATION OF INORGANIC MATERIALS WHICH ARE NO SINGLE CHEMICAL COMPOUNDS AND WHICH ARE MAINLY USED AS PIGMENTS OR FILLERS
- C09C3/00—Treatment in general of inorganic materials, other than fibrous fillers, to enhance their pigmenting or filling properties
- C09C3/10—Treatment with macromolecular organic compounds
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09C—TREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS, TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES ; PREPARATION OF CARBON BLACK ; PREPARATION OF INORGANIC MATERIALS WHICH ARE NO SINGLE CHEMICAL COMPOUNDS AND WHICH ARE MAINLY USED AS PIGMENTS OR FILLERS
- C09C3/00—Treatment in general of inorganic materials, other than fibrous fillers, to enhance their pigmenting or filling properties
- C09C3/12—Treatment with organosilicon compounds
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Abstract
The invention relates to surface-modified manganese sulfide which is obtaine d by providing manganese sulfide in powder form, adding 0.01 to 10 wt. % of a coating agent in relation to the weight of the manganese sulfide used and mixing the mixture for a long enough period to ensure that said mixture is homogeneous.
Description
Surface-modified manganese sulfide, method for producing the same and use thereof The invention relates to surface-modified manganese sulfide, a method foxy its preparation as well as the use of the surface-modified manganese sulfide as an auxiliary press material and as an additive in the sintering of molded articles. Furthermore r_he present invention relates to a sinter powder containing an amount of the surface-modified manganese sulfide, a method for the preparation of a molded article using the inventive sinter powder as well as a molded article obtainable by l.he method.
The machined processing, especially by cutting, of sintered 1!~ molded articles is often quite difficult due to tool wear and is alleviated by the addition of sulfides. Manganese sulfide (MnS) has proved to be an especially suitable additive for sintering, since its thermal stability allows it to participate in the sintering process without thermal degradation. For this, 1_he manganese sulfide must be incorporated into the :~:i.nter powder in as finely dispersed a form as possible. In the=_ U.S. patent 3,705,020, a manganese sulfide particle size o.f 10 to 100 ~,m, preferably 30 to 40 ~m is cited and., according to the European patent application EP
0 183 666, the particle size is 10 ~m or less. A small particle size enables homogeneous incorporation of the sulfide and the product:_ion of mechanically stable molded articles. In. particular,, the crack formation is reduced.
However, the small particle size and the large surface of the manganese sulfide associated therewith promotes its reaction with, in particular, moist air to MnO, Mn02 and MnS04 and, with this, a clumping together to larger particles or agglomerates. This behavior causes not only storage problems;
in the use cf the manganese sulfide as a sinter additive, the clumping then leads to a structural weakening of the finished molded articles. Especially under mechanical and thermal stress, the formation of. cracks and the destruction of the molded articles follow.
In the U.S. patent 5,768,678, the use of a special composition containing 'manganese sulfide as a sinter additive is proposed to avoid the oxidation of the manganese sulfide.
This composition is made of a mixture of 50-65 wt.o manganese, 30-38 wt.% :sulfur and 5-25 wt.% iron and is added to the metal powder' to be sintered in an amount 0.2-2.0 wt. o.
lc) According to this patent, the oxidation protection is afforded by the iron, which should be present in non-oxidized form. It is, however, ~~ disadvantage of the sinter additive of U.S. 5,768,678 that it contains additional useless iron sulfide and, furthermorE=, a surface reaction can be merely reduced but not avoided.. A further disadvantage of this sinter additive is its costly production.
There therefore exists a need for a storable and easily obtainable manganese st~7_fide. It is therefore the goal of the present invention to provide such a manganese sulfide without the features known in the prior a:rt.
The inventors have surprisingly found that such a manganese sulfide can :be obtained in that powdered manganese sulfide is provided, a ~~oating a~_Yent selected from a wax, an ester of an inorganic or organic acid or a polymer with a low melting point or mixtures thereof is selected, is added in an amount of 0.01 to 10 wt.% re=Lative to the weight of the manganese sulfide used, and the mixture is mixed over a period of time which is sufficient te:~ ensure a homogeneous mixture.
The studies of the inventors have indicated that the oxidation protection and the reduction of the moisture uptake by the otherwise hygrr~scopic material and the agglomeration resulting therefrom az:~e surprisingly prevented by even small amounts of the coating agent.
The machined processing, especially by cutting, of sintered 1!~ molded articles is often quite difficult due to tool wear and is alleviated by the addition of sulfides. Manganese sulfide (MnS) has proved to be an especially suitable additive for sintering, since its thermal stability allows it to participate in the sintering process without thermal degradation. For this, 1_he manganese sulfide must be incorporated into the :~:i.nter powder in as finely dispersed a form as possible. In the=_ U.S. patent 3,705,020, a manganese sulfide particle size o.f 10 to 100 ~,m, preferably 30 to 40 ~m is cited and., according to the European patent application EP
0 183 666, the particle size is 10 ~m or less. A small particle size enables homogeneous incorporation of the sulfide and the product:_ion of mechanically stable molded articles. In. particular,, the crack formation is reduced.
However, the small particle size and the large surface of the manganese sulfide associated therewith promotes its reaction with, in particular, moist air to MnO, Mn02 and MnS04 and, with this, a clumping together to larger particles or agglomerates. This behavior causes not only storage problems;
in the use cf the manganese sulfide as a sinter additive, the clumping then leads to a structural weakening of the finished molded articles. Especially under mechanical and thermal stress, the formation of. cracks and the destruction of the molded articles follow.
In the U.S. patent 5,768,678, the use of a special composition containing 'manganese sulfide as a sinter additive is proposed to avoid the oxidation of the manganese sulfide.
This composition is made of a mixture of 50-65 wt.o manganese, 30-38 wt.% :sulfur and 5-25 wt.% iron and is added to the metal powder' to be sintered in an amount 0.2-2.0 wt. o.
lc) According to this patent, the oxidation protection is afforded by the iron, which should be present in non-oxidized form. It is, however, ~~ disadvantage of the sinter additive of U.S. 5,768,678 that it contains additional useless iron sulfide and, furthermorE=, a surface reaction can be merely reduced but not avoided.. A further disadvantage of this sinter additive is its costly production.
There therefore exists a need for a storable and easily obtainable manganese st~7_fide. It is therefore the goal of the present invention to provide such a manganese sulfide without the features known in the prior a:rt.
The inventors have surprisingly found that such a manganese sulfide can :be obtained in that powdered manganese sulfide is provided, a ~~oating a~_Yent selected from a wax, an ester of an inorganic or organic acid or a polymer with a low melting point or mixtures thereof is selected, is added in an amount of 0.01 to 10 wt.% re=Lative to the weight of the manganese sulfide used, and the mixture is mixed over a period of time which is sufficient te:~ ensure a homogeneous mixture.
The studies of the inventors have indicated that the oxidation protection and the reduction of the moisture uptake by the otherwise hygrr~scopic material and the agglomeration resulting therefrom az:~e surprisingly prevented by even small amounts of the coating agent.
According to the invention coating agent is used in the production of the coated manganese sulfide in an amount of 0.01 wt.o to 10 wt.%, preferably 0.01 to 5 wt. o, especially preferred 1.0 to 3.0 wt~~ relative to the weight of the manganese sulfide.
Depending on the melt:i:2g point of the coating agent, the coating is generally carried out at a temperature of 20°C to 150°C. Depending on t.hf=_ coating agent used, one can however also operate at a ternpe:rature around the freezing point (0°C). Preferably, ore operates around room temperature, since then, the mixer does not have to be heated. The mixing is normally performed ~=or a period of time of 1 minute to 60 minutes, preferably for 5 minutes to 20 minutes.
Surprisingly, the manganese sulfide obtained in this way can be used directly, in other words it does not have to be submitted to further treatment steps such as drying for storage or for its use.
In addition to the use as a sinter additive for improving the processability o.f molded sinter articles, it was determined within of the scope of t:he present invention that the inventive surface-modified manganese sulfide also proves to be a lubricating press auxiliary and it can therefore be generally used as an additive for improving compression characteristics. A further advantageous characteristic of the inventive manganese sulfide, which proves to be very favorable in connection. with .its storage and use, is that it 3C is dustless.
The coating of the manganese sulfide can be performed in any way known to one of ord.i.nary skill in the art. The coating agent can be added to a conventional mixing apparatus such as a ploughsharf=_ mixer or_ a. tumbler-mixer all at once or in intervals. It is for example also possible to spray the coating agenl~ into the rriixing container. According to the invention, any normal manganese sulfide can be used, irrespective of its purity or particle size. If it is necessary, f:or exampi.e for the use as a sinter additive, the manganese sulfide is finely ground prior to coating, so that in general i.t has an a,~~?rage particle size, in other words a particle diameter, of :L to 200 urn, preferably of 1 to 10 Vim, and especially preferred of about 5 to 10 Vim. It is however also possible in this c=ase to use larger particles, as long as these confer sufficic=_nt mechanical stability in later sintering of the molded articles.
According th.e invention, compounds preferred as coating materials are either liquid at room temperature or have a relatively low melting point of under 150°C. In this way, and as indicated above, it is possible to operate without or only with very weak heating of the mixer in the production of the inventive manganese su1_f=ide .
For the use of the inventive manganese sulfide as a sinter additive, the inventive coating agent should furthermore have an evaporation temperature at normal pressure of under 500°C, preferably in the range of about 200 to 300°C and should decompose or evaporat:~ without residue during the heating of the sinter mixture, s:in.c:e in this way the formation of possible contaminations in the sintered molded article is reduced.
Coating mate=rials used according to the invention and possessing the previol.zsly cited physical characteristics are preferably low melon<~ polymers, oils including paraffinic oils and sil=icon oils, waxes, a mono- or mufti-functional aliphatic alcohol with 2 t=o 12 carbon atoms, organic and inorganic esi:ers, irl the latter case especially phosphoric acid esters.
One example of what is to be understood by waxes in the sense of the invent=ion are Easters of higher straight-chained fatty acids such a:~ palmitic:~ acid, hexaicosanoic acid with higher straight-cha:_ned, monofunctional alcohols such as palmityl alcohol, stearyl alcohol or octac~ec-9-en-1-ol. Another example of what is tc:~:be understood as waxes in the sense of the invention are materials which are mostly of natural origin, which contain. the fatty acid esters named above 5 partially or predomir:~antly, and which transition without degradation to a melting liquid, low viscous condition above approximately 30°C to <~0°C. An example of such waxes are Japan wax, lanolin or beeswax.
le) Furthermore, synthetic polymers, with waxy characteristics such as the so-called polyolefin waxes also fall under the definition of waxes here. Examples of such synthetic polymers which find application in the present invention are low-molecular polyethylene glycols and polypropylene glycols.
One example of what is too be 'understood as oils in the present invention are ~ili:phatic oils based on mineral oil such as the paraffinic oils. The aliphatic oils preferably have a chain length of 6 to 20 carbon atoms. The term oil also further encompasses synthetic oils such as the silicon oils such as known to ore of ordinary skill in the art as a general term inter al.iG~ for clear, colorless, hydrophobic liquids with congealing points of about -80 to -40°C from linear polydimethylsi:loxanes and polymethylphenylsiloxanes.
Compounds to be understood here as a low-melting polymer are those which consist of macromolecules and which have a melting poin~~ of underr 150°C and an evaporation temperature of under about 500°C at normal pressure. Preferred representatives of this class of compounds are polyesters, polyamides and polyal_i_phatic compounds.
According to the invention, esters of inorganic or organic acids can al:~o be usee~ a~~ the coating agent . Preferred inorganic acids are phosphoric acid and sulfuric acid however other acids can also be used according to the invention such as sulfur ac:~_ds, carbonic acid, ... . Formic acid and lower carbonic acids with 2 to 6 carbon atoms such as for example acetic acid are preferably used as organic acids. Aliphatic as well as aromatic alcohols are used as ester alcohols. The aliphatic a=~cohols preferably have a chain length of 1 to 20 C-atoms. Preferred az-omatic alcohols are the phenols. These can have mu7_tiple hydroxyl groups or multiple aliphatic substituent~~ with a chain length of preferably one to six C-atoms.
According to the invention, an alcohol which is to be understood as a mono- or multi-functional aliphatic alcohol with 2 to la: carbon at«ms is one which, due to its evaporation and flammability characteristics, is suitable for use in the inventive mE=_thod.
Aromatic compounds such as biphenyl etc. are also suitable as further coating agents, as long as these compounds, as with the other coating agenl:s usable according to the invention, are characterized by a low-soot and residue-free evaporation.
A preferred class coat=ing materials used according to the invention are (low-viscosity) esters of the phosphoric acids, in particular with lcnc~er chain aliphatic alcohols with chain lengths between 3 and =L5 C-atoms, preferably 6 to 13 C-atoms as well as with phencl;~ or other aromatic alcohols with side chains of 1 to 12 C-atoms, preferably 1 to 3 C-atoms such as cresol. These compound; are known to one skilled in the art as softeners. Examples of such compounds are tris-(2-ethylhexyl)-phosphate, t=ris(2-butoxyethyl)-phosphate, triphenylphosphate or ciiphenylcresylphosphate.
Diphenylcresylphosphate is an especially suitable representative of this class of compounds, since it is nontoxic, liquid at room temperature and has low viscosity, it evaporates at approx_Lmately 230°C and burns soot-free. A
further advantage of diphenylcresylphosphate is its relative temperature-independent: viscosity.
For the use as a sinter additive, the studies of the inventors have shown that a thusly surface-modified manganese sulfide improves the machined processing, especially by cutting, of sintered molded articles if the manganese sulfide is incorporated into a sinter powder in the amount of 0.1 wt.% to 1.0 wt.%, pref~=rably from 0.2 to 0.6 wt. o, relative to the weight of the sinter powder.
Accordingly, a further embodiment of the present invention is directed to a sinter powder characterized by an amount of the inventive manganese su:L:fide.
For use as an additive :in sintering, the manganese sulfide is preferably treated with the inventive coating agents in the manner explained above prior to the addition to the selected metal powder. However __t= is also possible within the scope of 1> the invention to first rnix unmodified manganese sulfide with the metal powder to be ;sintered and finally to add the coating agent to the sinter mixture.
A further embodiment of: the present invention therefore also relates to a method foxy producing a molded article using the inventive sinter powder, wherein the method comprises the following steps:
a) compression of the' sinter powder :in a sinter mold having an inner shape corresponding to the end contour of the 2~~ finished molded article;
b) heating the green compact to a temperature above the evaporation temperature of the coating agent used in the production of the manganese ;sulfide and, if necessary, maintaining the green compact at this temperature for a period of time s~.zfficient to ensure complete evaporation of the ~~oating agent;
c) sintering the gr~-yen compact from step b) ;
d) removing the cooled molded product. from the sinter mold.
A further embodiment therefore encompasses a molded article obtainable b~~ the inventive production/sinter method elaborated above.
Depending on the melt:i:2g point of the coating agent, the coating is generally carried out at a temperature of 20°C to 150°C. Depending on t.hf=_ coating agent used, one can however also operate at a ternpe:rature around the freezing point (0°C). Preferably, ore operates around room temperature, since then, the mixer does not have to be heated. The mixing is normally performed ~=or a period of time of 1 minute to 60 minutes, preferably for 5 minutes to 20 minutes.
Surprisingly, the manganese sulfide obtained in this way can be used directly, in other words it does not have to be submitted to further treatment steps such as drying for storage or for its use.
In addition to the use as a sinter additive for improving the processability o.f molded sinter articles, it was determined within of the scope of t:he present invention that the inventive surface-modified manganese sulfide also proves to be a lubricating press auxiliary and it can therefore be generally used as an additive for improving compression characteristics. A further advantageous characteristic of the inventive manganese sulfide, which proves to be very favorable in connection. with .its storage and use, is that it 3C is dustless.
The coating of the manganese sulfide can be performed in any way known to one of ord.i.nary skill in the art. The coating agent can be added to a conventional mixing apparatus such as a ploughsharf=_ mixer or_ a. tumbler-mixer all at once or in intervals. It is for example also possible to spray the coating agenl~ into the rriixing container. According to the invention, any normal manganese sulfide can be used, irrespective of its purity or particle size. If it is necessary, f:or exampi.e for the use as a sinter additive, the manganese sulfide is finely ground prior to coating, so that in general i.t has an a,~~?rage particle size, in other words a particle diameter, of :L to 200 urn, preferably of 1 to 10 Vim, and especially preferred of about 5 to 10 Vim. It is however also possible in this c=ase to use larger particles, as long as these confer sufficic=_nt mechanical stability in later sintering of the molded articles.
According th.e invention, compounds preferred as coating materials are either liquid at room temperature or have a relatively low melting point of under 150°C. In this way, and as indicated above, it is possible to operate without or only with very weak heating of the mixer in the production of the inventive manganese su1_f=ide .
For the use of the inventive manganese sulfide as a sinter additive, the inventive coating agent should furthermore have an evaporation temperature at normal pressure of under 500°C, preferably in the range of about 200 to 300°C and should decompose or evaporat:~ without residue during the heating of the sinter mixture, s:in.c:e in this way the formation of possible contaminations in the sintered molded article is reduced.
Coating mate=rials used according to the invention and possessing the previol.zsly cited physical characteristics are preferably low melon<~ polymers, oils including paraffinic oils and sil=icon oils, waxes, a mono- or mufti-functional aliphatic alcohol with 2 t=o 12 carbon atoms, organic and inorganic esi:ers, irl the latter case especially phosphoric acid esters.
One example of what is to be understood by waxes in the sense of the invent=ion are Easters of higher straight-chained fatty acids such a:~ palmitic:~ acid, hexaicosanoic acid with higher straight-cha:_ned, monofunctional alcohols such as palmityl alcohol, stearyl alcohol or octac~ec-9-en-1-ol. Another example of what is tc:~:be understood as waxes in the sense of the invention are materials which are mostly of natural origin, which contain. the fatty acid esters named above 5 partially or predomir:~antly, and which transition without degradation to a melting liquid, low viscous condition above approximately 30°C to <~0°C. An example of such waxes are Japan wax, lanolin or beeswax.
le) Furthermore, synthetic polymers, with waxy characteristics such as the so-called polyolefin waxes also fall under the definition of waxes here. Examples of such synthetic polymers which find application in the present invention are low-molecular polyethylene glycols and polypropylene glycols.
One example of what is too be 'understood as oils in the present invention are ~ili:phatic oils based on mineral oil such as the paraffinic oils. The aliphatic oils preferably have a chain length of 6 to 20 carbon atoms. The term oil also further encompasses synthetic oils such as the silicon oils such as known to ore of ordinary skill in the art as a general term inter al.iG~ for clear, colorless, hydrophobic liquids with congealing points of about -80 to -40°C from linear polydimethylsi:loxanes and polymethylphenylsiloxanes.
Compounds to be understood here as a low-melting polymer are those which consist of macromolecules and which have a melting poin~~ of underr 150°C and an evaporation temperature of under about 500°C at normal pressure. Preferred representatives of this class of compounds are polyesters, polyamides and polyal_i_phatic compounds.
According to the invention, esters of inorganic or organic acids can al:~o be usee~ a~~ the coating agent . Preferred inorganic acids are phosphoric acid and sulfuric acid however other acids can also be used according to the invention such as sulfur ac:~_ds, carbonic acid, ... . Formic acid and lower carbonic acids with 2 to 6 carbon atoms such as for example acetic acid are preferably used as organic acids. Aliphatic as well as aromatic alcohols are used as ester alcohols. The aliphatic a=~cohols preferably have a chain length of 1 to 20 C-atoms. Preferred az-omatic alcohols are the phenols. These can have mu7_tiple hydroxyl groups or multiple aliphatic substituent~~ with a chain length of preferably one to six C-atoms.
According to the invention, an alcohol which is to be understood as a mono- or multi-functional aliphatic alcohol with 2 to la: carbon at«ms is one which, due to its evaporation and flammability characteristics, is suitable for use in the inventive mE=_thod.
Aromatic compounds such as biphenyl etc. are also suitable as further coating agents, as long as these compounds, as with the other coating agenl:s usable according to the invention, are characterized by a low-soot and residue-free evaporation.
A preferred class coat=ing materials used according to the invention are (low-viscosity) esters of the phosphoric acids, in particular with lcnc~er chain aliphatic alcohols with chain lengths between 3 and =L5 C-atoms, preferably 6 to 13 C-atoms as well as with phencl;~ or other aromatic alcohols with side chains of 1 to 12 C-atoms, preferably 1 to 3 C-atoms such as cresol. These compound; are known to one skilled in the art as softeners. Examples of such compounds are tris-(2-ethylhexyl)-phosphate, t=ris(2-butoxyethyl)-phosphate, triphenylphosphate or ciiphenylcresylphosphate.
Diphenylcresylphosphate is an especially suitable representative of this class of compounds, since it is nontoxic, liquid at room temperature and has low viscosity, it evaporates at approx_Lmately 230°C and burns soot-free. A
further advantage of diphenylcresylphosphate is its relative temperature-independent: viscosity.
For the use as a sinter additive, the studies of the inventors have shown that a thusly surface-modified manganese sulfide improves the machined processing, especially by cutting, of sintered molded articles if the manganese sulfide is incorporated into a sinter powder in the amount of 0.1 wt.% to 1.0 wt.%, pref~=rably from 0.2 to 0.6 wt. o, relative to the weight of the sinter powder.
Accordingly, a further embodiment of the present invention is directed to a sinter powder characterized by an amount of the inventive manganese su:L:fide.
For use as an additive :in sintering, the manganese sulfide is preferably treated with the inventive coating agents in the manner explained above prior to the addition to the selected metal powder. However __t= is also possible within the scope of 1> the invention to first rnix unmodified manganese sulfide with the metal powder to be ;sintered and finally to add the coating agent to the sinter mixture.
A further embodiment of: the present invention therefore also relates to a method foxy producing a molded article using the inventive sinter powder, wherein the method comprises the following steps:
a) compression of the' sinter powder :in a sinter mold having an inner shape corresponding to the end contour of the 2~~ finished molded article;
b) heating the green compact to a temperature above the evaporation temperature of the coating agent used in the production of the manganese ;sulfide and, if necessary, maintaining the green compact at this temperature for a period of time s~.zfficient to ensure complete evaporation of the ~~oating agent;
c) sintering the gr~-yen compact from step b) ;
d) removing the cooled molded product. from the sinter mold.
A further embodiment therefore encompasses a molded article obtainable b~~ the inventive production/sinter method elaborated above.
The present invention. is to be described by way of one non-limiting example.
Example 1: Preparation of surface-modified manganese sulfide 20 g of liquid dipher~y:Lcresylphosphate were added to 2000 g of manganese sulfide with a particle diameter of 4.96 ~m (D50) in a L~oedige-mixer. The batch was subsequently mixed at 25°C for 20 minutes.
Determinaticn of the resistance to oxidation The manganese sulfide, which had been treated with to diphenylcresylphosphate,, obtained in Example 1 was stored with uncoated manganese. sulfide of the same particle diameter, that is according to EP 0 183 666 (Example 2) as well as with a mangane~>e sulfide composition to U.S.
5,768,678 (Example 3) i.n an atmosphere of 75o humidity at room temperature for 6 days. Subsequently the extent of oxidation of the manganese sulfide on the surface to MnO, MnOz and MnSO4 (according to the schematic reactions MnS + H20 => MnO; Mn02; MnS04) wa~~ determined for every sample by measurement of the weight increase (Table 1).
Table 1 Weiq:ht increase_after 6 days Particle size D50 Weight increase Example Manganese Sulfide (gym) (%) 1 Inventive MnS 4.69 0.2 2 Uncoated MnS 4.49 25.8 3 MnS with :LO°s FeS 7.98 11.1 As can be SeE=_n in Tab_l.e 1, the inventive coated manganese sulfide absorbs significantly less moisture than the uncoated material or t=he manganese sulfide composition of U.S.
5,768,678. In standing with this, the inventive material is still a fine, free-flowing powder lacking agglomerates after 10 weeks, while during this same time the uncoated manganese sulfide changed to a c:~oarse-grained, dark product due to absorption of moistux-e and the formation of manganese dioxide.
Example 1: Preparation of surface-modified manganese sulfide 20 g of liquid dipher~y:Lcresylphosphate were added to 2000 g of manganese sulfide with a particle diameter of 4.96 ~m (D50) in a L~oedige-mixer. The batch was subsequently mixed at 25°C for 20 minutes.
Determinaticn of the resistance to oxidation The manganese sulfide, which had been treated with to diphenylcresylphosphate,, obtained in Example 1 was stored with uncoated manganese. sulfide of the same particle diameter, that is according to EP 0 183 666 (Example 2) as well as with a mangane~>e sulfide composition to U.S.
5,768,678 (Example 3) i.n an atmosphere of 75o humidity at room temperature for 6 days. Subsequently the extent of oxidation of the manganese sulfide on the surface to MnO, MnOz and MnSO4 (according to the schematic reactions MnS + H20 => MnO; Mn02; MnS04) wa~~ determined for every sample by measurement of the weight increase (Table 1).
Table 1 Weiq:ht increase_after 6 days Particle size D50 Weight increase Example Manganese Sulfide (gym) (%) 1 Inventive MnS 4.69 0.2 2 Uncoated MnS 4.49 25.8 3 MnS with :LO°s FeS 7.98 11.1 As can be SeE=_n in Tab_l.e 1, the inventive coated manganese sulfide absorbs significantly less moisture than the uncoated material or t=he manganese sulfide composition of U.S.
5,768,678. In standing with this, the inventive material is still a fine, free-flowing powder lacking agglomerates after 10 weeks, while during this same time the uncoated manganese sulfide changed to a c:~oarse-grained, dark product due to absorption of moistux-e and the formation of manganese dioxide.
Claims (15)
1. Surface coated manganese sulfide, obtainable in that powdered manganese sulfide is provided, a coating agent, preferably selected from the group consisting of a wax, an ester of an inorganic or organic acid, an oil, a low-melting polymer, a mono- to multi-functional aliphatic alcohol with 2 to 12 carbon atoms or mixtures thereof, is added in an amount of 0.01 to 10 wt.% relative to the weight of the manganese sulfide used, and the mixture is mixed for a period of time which is sufficient to ensure a homogeneous mixture.
2. Manganese sulfide according to claim 1, characterized in that the powdered manganese sulfide has a particle size of 1 to 200 µm, preferably 1 to 10 µm.
3. Manganese sulfide according to claim 1 or 2, characterized in that the low melting polymer has a melting point under 150°C and is a polyester, polyamide or a polyaliphatic compound.
4. Manganese sulfide according to claim 1 and 2, characterized in that the ester of the inorganic acid is a phosphoric acid ester.
5. Manganese sulfide according to claim 4, characterized in that the phosphoric acid ester is diphenylcresylphosphate or triphenylphosphate.
6. Manganese sulfide according to claim 1 or 2, characterized in that the oil is a paraffinic oil or silicon oil.
7. Method for producing surface-modified manganese sulfide (MnS), characterized in that powdered manganese sulfide is provided, a coating agent, selected from the group consisting of a wax, an ester of an inorganic or an organic acid, an oil, a low melting polymer, a mono- to mufti-functional aliphatic alcohol with 2 to 12 carbon atoms or mixtures thereof, is added in an amount of 0.01 to 10 wt.% relative to the weight of the manganese sulfide used, and the mixture is mixed for a period of time which is sufficient to ensure a homogeneous mixture.
8. Method according to claim 7, characterized in that the manganese sulfide has a particle size from 1 to 200 µm, probably from 1 to 10 µm.
9. Method according to claim 7 or 8, characterized in that the coating agent is added in an amount of 0.01 to 5.0 wt. %, especially preferably from 1.0 to 3.0 wt.%, relative to the weight of the manganese sulfide used.
10. Method according to any of the claims 7 to 9, characterized in that the ester of the inorganic acid is a phosphoric acid ester.
11. Method according to claim 10, characterized in that the ester of the phosphoric acid is diphenylcresylphosphate or triphenylphosphate.
12. Use of the manganese sulfide according to any of the claims 1 to 6 as an additive for improving the compression characteristics of powder mixtures.
13. Use of the manganese sulfide according to any of claims 1 to 6 as an additive to sinter powders for improving the processability of the molded sintered article.
14. Sinter powder, characterized by a content of manganese sulfide according to one of the claims 1-6.
15. Method for producing a molded article using the sinter powder according to claim 14, comprising the following steps:
a) compression of the sinter powder in a sinter mold that has an inner shape corresponding to the final contour of the finished molded article;
b) heating the green compact to a temperature above the evaporation temperature of the coating agent used for production of the manganese sulfide and, if necessary, maintaining the green compact at this temperature for a period of time sufficient to ensure complete evaporation of the coating agent;
c) sintering the green compact of step b);
d) removing the cooled molded article from the sinter mold.
16. Molded article, obtainable by the method according to
15. Method for producing a molded article using the sinter powder according to claim 14, comprising the following steps:
a) compression of the sinter powder in a sinter mold that has an inner shape corresponding to the final contour of the finished molded article;
b) heating the green compact to a temperature above the evaporation temperature of the coating agent used for production of the manganese sulfide and, if necessary, maintaining the green compact at this temperature for a period of time sufficient to ensure complete evaporation of the coating agent;
c) sintering the green compact of step b);
d) removing the cooled molded article from the sinter mold.
16. Molded article, obtainable by the method according to
claim 15.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19943510.3 | 1999-09-10 | ||
| DE19943510A DE19943510C1 (en) | 1999-09-10 | 1999-09-10 | Surface coated manganese sulfide, used as additive for pressing or sintering powder, is produced by mixing powder with small amount of wax, ester, oil, low-melting polymer or aliphatic alcohol |
| PCT/EP2000/008626 WO2001019929A1 (en) | 1999-09-10 | 2000-09-04 | Surface-modified manganese sulfide, method for producing the same and use thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2347824A1 true CA2347824A1 (en) | 2001-03-22 |
Family
ID=7921630
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002347824A Abandoned CA2347824A1 (en) | 1999-09-10 | 2000-09-04 | Surface-modified manganese sulfide, method for producing the same and use thereof |
Country Status (13)
| Country | Link |
|---|---|
| EP (1) | EP1137718B1 (en) |
| JP (1) | JP2003509325A (en) |
| KR (1) | KR20010082294A (en) |
| AT (1) | ATE256716T1 (en) |
| BR (1) | BR0007095A (en) |
| CA (1) | CA2347824A1 (en) |
| DE (2) | DE19943510C1 (en) |
| DK (1) | DK1137718T3 (en) |
| ES (1) | ES2209999T3 (en) |
| PL (1) | PL347575A1 (en) |
| PT (1) | PT1137718E (en) |
| TR (1) | TR200101158T1 (en) |
| WO (1) | WO2001019929A1 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6445555B1 (en) | 1999-11-24 | 2002-09-03 | American Superconductor Corporation | Method and apparatus for discharging a superconducting magnet |
| KR100437643B1 (en) * | 2001-11-30 | 2004-06-30 | 가야에이엠에이 주식회사 | compositions of manganese sulfide compound an addition for making sintered goods |
| KR102312281B1 (en) * | 2021-04-26 | 2021-10-12 | 대영소결금속 주식회사 | Manganese sulfide composition for sintering material manufacturing |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3705020A (en) * | 1971-02-02 | 1972-12-05 | Lasalle Steel Co | Metals having improved machinability and method |
| SE427434B (en) * | 1980-03-06 | 1983-04-11 | Hoeganaes Ab | IRON-BASED POWDER MIXED WITH ADDITION TO MIXTURE AND / OR DAMAGE |
| SE445715B (en) * | 1984-11-30 | 1986-07-14 | Hoeganaes Ab | MANGANESULPHIDIC IRON POWDER MIXTURE |
| US4834800A (en) * | 1986-10-15 | 1989-05-30 | Hoeganaes Corporation | Iron-based powder mixtures |
| FR2724851B1 (en) * | 1994-09-26 | 1997-01-17 | Francais Prod Ind Cfpi | SIMULTANEOUSLY ANTIMOTTANT AND WATERPROOFING COMPOSITION FOR SALTS, SINGLE AND COMPLEX FERTILIZERS AND METHOD FOR IMPLEMENTING SAME |
| US5768678A (en) * | 1996-05-08 | 1998-06-16 | Pyron Corporation | Manganese sulfide composition and its method of production |
| DE69717099T2 (en) * | 1997-09-02 | 2003-03-27 | Federal-Mogul Deva Gmbh | Use of stainless sintered steel alloy with manganese sulphi for bearings subject to high temperatures. |
-
1999
- 1999-09-10 DE DE19943510A patent/DE19943510C1/en not_active Expired - Fee Related
-
2000
- 2000-09-04 PL PL00347575A patent/PL347575A1/en unknown
- 2000-09-04 JP JP2001523702A patent/JP2003509325A/en active Pending
- 2000-09-04 EP EP00965916A patent/EP1137718B1/en not_active Expired - Lifetime
- 2000-09-04 CA CA002347824A patent/CA2347824A1/en not_active Abandoned
- 2000-09-04 DE DE50004789T patent/DE50004789D1/en not_active Expired - Fee Related
- 2000-09-04 AT AT00965916T patent/ATE256716T1/en not_active IP Right Cessation
- 2000-09-04 PT PT00965916T patent/PT1137718E/en unknown
- 2000-09-04 TR TR2001/01158T patent/TR200101158T1/en unknown
- 2000-09-04 WO PCT/EP2000/008626 patent/WO2001019929A1/en not_active Application Discontinuation
- 2000-09-04 BR BR0007095-5A patent/BR0007095A/en not_active Application Discontinuation
- 2000-09-04 KR KR1020017005899A patent/KR20010082294A/en not_active Application Discontinuation
- 2000-09-04 ES ES00965916T patent/ES2209999T3/en not_active Expired - Lifetime
- 2000-09-04 DK DK00965916T patent/DK1137718T3/en active
Also Published As
| Publication number | Publication date |
|---|---|
| ES2209999T3 (en) | 2004-07-01 |
| PL347575A1 (en) | 2002-04-08 |
| KR20010082294A (en) | 2001-08-29 |
| DK1137718T3 (en) | 2004-04-13 |
| TR200101158T1 (en) | 2001-08-21 |
| BR0007095A (en) | 2001-07-31 |
| DE50004789D1 (en) | 2004-01-29 |
| DE19943510C1 (en) | 2001-01-25 |
| EP1137718B1 (en) | 2003-12-17 |
| WO2001019929A1 (en) | 2001-03-22 |
| EP1137718A1 (en) | 2001-10-04 |
| ATE256716T1 (en) | 2004-01-15 |
| JP2003509325A (en) | 2003-03-11 |
| PT1137718E (en) | 2004-05-31 |
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| EEER | Examination request | ||
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