CA2469461A1 - A coating for the working surface of the cylinders of combustion engines and a method of applying such a coating - Google Patents
A coating for the working surface of the cylinders of combustion engines and a method of applying such a coating Download PDFInfo
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- CA2469461A1 CA2469461A1 CA002469461A CA2469461A CA2469461A1 CA 2469461 A1 CA2469461 A1 CA 2469461A1 CA 002469461 A CA002469461 A CA 002469461A CA 2469461 A CA2469461 A CA 2469461A CA 2469461 A1 CA2469461 A1 CA 2469461A1
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C4/00—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge
- C23C4/04—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge characterised by the coating material
- C23C4/06—Metallic material
- C23C4/08—Metallic material containing only metal elements
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C4/00—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge
- C23C4/04—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge characterised by the coating material
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C4/00—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge
- C23C4/12—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge characterised by the method of spraying
- C23C4/14—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge characterised by the method of spraying for coating elongate material
- C23C4/16—Wires; Tubes
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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Plasma & Fusion (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Coating By Spraying Or Casting (AREA)
Abstract
Ferrous coatings of the cylinder working surfaces of combustion engine blocks have a content of bound oxygen in the amount of between 1 to 4% by weight.
They are characterized by extraordinary properties as far as tribology and the possibility of processing, e.g. machining, are concerned. Particularly, the coefficient of friction and the tendency to scuffing are substantially reduced. Such coatings can be realized, for example, by adding an amount of 200 to 1000 normalized liters air per minute during the plasma spraying operation.
They are characterized by extraordinary properties as far as tribology and the possibility of processing, e.g. machining, are concerned. Particularly, the coefficient of friction and the tendency to scuffing are substantially reduced. Such coatings can be realized, for example, by adding an amount of 200 to 1000 normalized liters air per minute during the plasma spraying operation.
Description
A COATING t=OR THE WORtCING SURFACE OF THE CYLINDERS OF
COMBUSTION ENGINES AND A MI'THOD OF APPL~'fNG SUCH A COATING
This is a divisional of application Serial No. 2,296,155 filed January 17, 2000.
Backaround of the Invention The present invention refers to a ferrous coating applied by a plasma spraying operation to a substrate serving as a cylinder working surface of a combustion engine block. Moreover, the invention also refers to a method of applying a ferrous coating to a substrate serving as a cylinder working surface of a combustion engine block.
Prior Art In the prior art, the traditional material for the working surfaces of the cylinders of combustion engine blocks that are made of aluminum or magnesium alloy is constituted by grey cast iron or cast iron blended with compacted graphite. Thereby, cylinder sleeves made of such cast iron are pressed or cast into these combustion engine blocks.
By providing such cylinder sleeves, however, on the one hand the size and the weight of the engine block is influenced in a negative sense. On the other hand, an in-convenient or adverse connection between the cylinder sleeves made of cast iron end the engine block made of a light metal alloy must be taken into account.
Alternatively, also coatings applied by a galvanising process have been used. However, the applica-tion of such coating is expensive and, moreover, such coatings may corrode under the influence of sulfuric acid and formic acid.
- z -Furthermore, the application of a coating to bores in gene.rat by means of a plasma spraying operation is known in the art for a long time. Thereby, a variety of me-lallic matenais can be applied to the substrate. Once the coating has been applied by means of the plasma spraying operation, the bores are further processed by diamond honing to rEach their desired fnai diameter and provided with the desired topography.
The ability of the coating to be processed and machined, respectively, and the tribologic properties are depending to a high degree on the microstructure and the physical prop-erties of the particular coating.
Objects of the Invention It is an object of the present invention to improve the machining and processing, respectively, as well as the tribotogic properties of ferrous coatings for the working sur-faces of combustion engine cylinder blocks applied by a plasma spraying operation.
z Sumrn_ary of the invention !n order to meet this and other objects, the invention provides, in a first aspect, a ferrous coating applied by a plasma spraying operation to a substrate serving as a cyl-finder working surface of a combustion engine block, whereby the coating has a content of bound oxygen of between 1 % and 4% by weight.
"fhe inventiøn is based on the surprising observation that a microstructure can be created by means of a specially controlled reaction of the powder used far the coating and oxygen during a plasma spraying operation, i.e_ a microstructure comprising out standing properties as far as machining and processing, respectively, as well as tri-boiogy are concerned. Particularly, the coefficient of friction and the tendency towards scuffing, i_e. the beginning of adhesive wear, are drastically decreased.
As previously mentioned, the coating of the invention, applied by plasma spray-ing, has a content of bound oxygen of between 1 and 4% by weight. As a substrate for applying such a coating, particularly suitable are:
~ !he cylinder bores of combustion engine cylindEr blocks made of an aluminum or a mar~nesium alloy or of cast iron;
~ the inner wall of sleeves made of cast iron and inserted into a combustion cn~
give cylinder block made of an aluminum or a magnesium alloy.
In a preferred embodiment, the bound oxygen forms, together with the iron, Fe0 and Fe304 crystals in the coating. Thereby, if is preferred that the content of Fez43 amounts to less than 0.2% by weight. The amount of the formed oxides can be further controlled by mixing the air with nitrogen or oxygen. if the air is replaced by pure oxy-gen, the content of bound oxygen in the coating is reduced by a factor of about two.
. .... _.. .. .,. ~ -_ . ,~ . _ r , .,. ..,r ~ w.~ .a~.~. .,w ..., .
~._w_.~~~m..~ ..~..~m~,~,~."«.-.~-..~: -~-.rt.., _.~.._.. _..._. _ .~.._ In a second aspect, the invention also refers to a method of applying a ferrous . .
coating to a substrate serving as a cylinder working surface of a combustion engine black. The method comprises the steps of providing a plasma spraying apparatus, pro-viding a coating powder constituting the raw material of the coating to be applied, spraying the coating powder by means of the plasma spraying apparatus onto the cylin-der working surface; and either ~ supplying air to the plasma spraying apparatus and spraying the air simuita-neously with the coating powder onto the substrate in an amount of between 200 and.1000 normalized liters per minute; or supplying an oxygen containing gas to the plasma spraying apparatus and spraying the oxygen containing gas simultaneously with the coating powder onto the substrate in an amount of between 40 and 200 normalized titers oxy-gen per minute; or ~ supplying oxygen to the plasma spraying apparatus and spraying the oxygen simultaneously with the coating powder onto the substrate in an amount of between 40 and 200 normalized liters per minute.
The expression "normalized liters per minute" shat) be understood as "liters per minute at an ambient pressure of 1 bar (~ 10' Pa) and a temperature of 20° C. Prefera-bly, the velocity of the gas flow in the interior of the sleeve or cylinder bore amounts to between 7 and 12 m/s during the plasma spraying operation.
in a preferred embodiment, a gas atomized powder is plasma sprayed to the substrate, whereby the powder has the following composition:
C = 0.4 to 1.5°/a by weight ......w._ .~ .~._._". r...~..~ ~.~. .~.~ ..~ ~~_~ ~_ _.~._~~~ ~.~ _~. _.,.
...... __ . . . .. . . ___..~_....~ ~ ~,. ,.~... ......_ ___. r.
Cr ~ 0_2 to 2.5% by weight Mn = O.a2 to 3% by weight i' = O.D1 to 0_ 1 % by weight, if appropriate S = 0.01 t~ 0.2% by weight, if appropriate Fe = difference to 100~/o by weight, in anoti~er preferred ernbadiment, a gas atomized powder is plasma sprayed to the substrate, whereby the powder has the following composition:
C - 0_1 to 0.8°1° by weight Cr = ~( 1 to 18% by weight Mtl = 0.7 to 1 _5% by weight Mo = 0_1 to 5%, by weight S ~ O.D1 to 0.2% by weight, if appropriate P = 0.07 to 0.1 % by weight, if appropriate he = difference to 100% by weight.
The amount of FeQ and Fe~04 in the coating can be influenced by the distribu, lion of the size of thc; particies of the powder. Depending on the coating to be realized, the size of the particles of the powder can be in the region of between 5 to 25 pm, in the rE:gion of between 10 to 40 frm, or in the region of between 15 to f~0 l.rm.
The size of the pertic(es can be determined by means of an optical or an electronic microscope, par-ticularly by means of a scanning microscope, ar according to the laser diffraction mraiiod MICRC~TRAC.' Preferably, a coating powder is used that has been gas atomized by means of argon or nitrogen.
The best results can be obtained if a coating powder is used that is blended with a tribofogic oxide ceramics. Preferably, the oxide ceramics consists of TiOz or A1~03Ti(J~
and/or Afz03Zr02 alloy systems. The portion of the oxide ceramics in the coating pow, der can amount to between 5 and 5D% by weight.
It should be noted That the optimum particle size is selected according to the tri-bologic properties of the coating to be applied and according to the mechanical behavior of the substrate to which the coating has to be applied.
brief Descrit~tion of the Drawin s In the following; some examples of a coating according to the invention will be further described_ In the accompanying drawings:
Fig. 1 shows a diagram illustrating the relation between the particle size of the coating powder and the decrease of the coefficient of friction as welt as the relation be-tween the particle size of the coating powder and the mechanical characteristics, ~par-ticula~iy the adhesive strength of the coating; and Fig. 2 shows a diagrarr~ illustrating the relation between the amount of bound oxygen in the coating and the decrease of the coefficient of friction as welt as the refa-lion between the amount of bound oxygen in the coating and the mechanical character-istics, particularly the adhesive strength of the coating.
Example 1 A coating powder has been applied to the working surface of a cylinder sleeve of a combustion engine by means of a plasmatran. The coating powder had the following composition-C = 9 .1 % by weight .
Cr = i .5°/a by Weight Mn = '( _5% by weight Fe = difference to 900% by weight.
If appropriate, the coating powder may also contain S and P in small amounts (i.e. 0.01 to 0.2% by weight).
TY~e size of the particles of the coating powder was between 5 and 25 lrm. The powder has been manufactured by a gas atomizing process. The velocity of the gas ff~~w Burin c~ the operation of applying the coating was 't t7 rn/s, and the amount of air fed to fhe plasmatron for cooling the coating and for the reaction of the powder was 500 NLIaM (nc~rmaiized liters per minute). This corresponds to about 100 NLPM pure oxy-gen. That amount of air was fed through the body of a plasmatron welt known in the art, e.g. as described in U.S. Patent No. 5,519,183.
The results of the experiments that have been run have shown that the content of oxygen in the applied coating was in the region of 3°/a by weight.
According to a macro structural analysis performed by means of X-rays, the oxygen is bound according to the stoichiometric formulas Fe0 and Fe30~,. Moreover, that analysis has shown that the presonce of Fo203 is below the detectable limit.
The coating having been applied, the cylinder sleeve was further processed by diamond honing. Experiments with a combustion engine provided with such cylinder sleeves have clearly confirmed that the coefficient of friction between the piston rings and the wall of the cylinder sleeve is substantially reduced, as compared to well known cylinder sleeves made of grey cast iron.
Example 2 A, powder was used having the same composition as in Example 1 herein before;, but with a particle size of between 10 and 45 ~tm. Moreover, ail other conditions were identical to the ones described ire Example 1. Thereby, it was found that the content of bound oxygen in the applied coating was in the region of 2% by weight. The other re-sults of an analysis of the coating were the same as explained in connection with Ex-ample 1.
The coating having been applied, the cylinder sleeve was further processed by diamond honing. Experiments with a combustion engine provided with such cylinder sleeves have clearly confirmed that the coefficient of friction between the piston rings and the working surface of the cylinder sleeve again is substantially reduced, as com-pared to well known cylinder Sleeves made of grey cast iron, whereby the reduction of the coefficient of fr7ction is in relation to the amount of bound oxygen.
~xam~Ie~3 Cylinder sleeves that are to lie used with combustion engines operated with sul-phurous fuel ar With methanol, such engines being subject to corrosion when they are operated at temperatures below the dew-point at the given conditions, have been coated, under the same conditions as described in Example 1, with a powder having the following composition:
C = 0_~.°r° by weight Cr = 13.0% by weight Mn ~ 1.5% by weight Mo = 2.0% by weight .,....m __ ....._ .. ~ .1...<."~ ~..~, x..M~.~. ....._._- ...._.
.. c~ ...
Fe = difference to 100°la by weight.
ft appropriate, the coating powder may also contain S and P in small amounts (i.e. 0.01 to 0.2°l° by weight).
The-: size c~f the particles of the coating powder was between 10 and 45 Nm.
The tests that have been run using such a coating yielded substantially the same I~-worabla results as explained in Examples '1 and 2.
Example 4 The same procedure was performed as described in Example: 2, except that 30%
by weictht of an ceramics alloy powder was added to the coating powder, the ceramics alloy powder having a composition of 60°!° by weight AIZO~ and 40% by weight TiQ2.
The coatings created using such a powder are rtfechanicaliy reinforced due to the inclu-lion of the ceramics particles with a size of between ~ and 22 pm.
_ _ n _,.-..~,~,x..~:_~. ~-~:.~~....~~_~_.. ._ __ ._ _.____.____ . _. _ __ _.___-_~_....~.....~___~__.. _ , _ __ - so -Example r ~i'he same procedure was repeated as described in Example 4, except that 30%
by weight of a ceramics alloy powder was added to the coating powder, the ceramics alloy powder having a composition of SO% by weight A1203 and 20% by weight Ti02.
The coatings created using such a powder are mechanically reinforced due to the inclu-sion of the ceramics particles with a size of befween 5 and 22 frm.
Fig. 1 shows a diagram illustrating the relation between the particle size of the coating powder and the decrease of the coefficient of friction as well as the relation be-tween the particle size of the coating. powder and the mechanical characteristics, par-ticularly the adhesive strength of the coating. It Is evident tram the diagram, on the one hand, that the coefficient of friction gets lower if the size of the particles is increased. On the other hand, the adhesive strength is gradually reduced if the particle size is in-creased. A goad compromise may be a particle size in the region of 25 to 30 um, whereby the adhesive strength amounting to appr. 45-50 MPa should be sufficient in most cases while the coefficient of friction is stilt reduced, as compared to the prior art coatings, 6y about 22-25%. However, if adhesive strength is the primary goal and the reduction of the coefficient of friction is but of secondary importance, one would chose a coating powder having particles with a smaller size. In another application, in which the reduction of the coeificient of friction is the primary goa! and the adhesive strength of tile coating is less important, ono would chose a coating powder having particles with a greater size.
Fig. 2 shows a diagram illustrating the relation between the amount of bound oxygen in the coating and decrease of the coefficient of friction as well as the rotation ..
between the amount of bound oxygen in the coating and mechanical characteristics, parCicutariy the adhesive strength of the coating. tt is evident from the diagram, on the orro hand, that the coefficient of friction gets lower if the amount of bound oxygen in the coating is increased. On the other hand, the adhesive strength is reduced if the amount of bound oxygen in the coating is increased. A good compromise may be a content of bound oxycden in the region of between 2-2.5% by weight, whereby the adhesive strength amounting to appr. 40-~t~ MPs should be sufficient in most cases while the co-efficient of friction is still reduced, as compared to the prior art coatings, by about 20-25%: Correspondingly to what is explained in connection with !=ig. 1, i.e. if adhesive strength is the primary goal and the reduction of the coefficient of friction is but of sec-ondary importance, one would strive for realizing a tower content of bound oxygen in the coating. tn another application, in which the reduction of the coefficient of friction is the primary goal and the adhesive strength of the coating is Less important, one would strive for realizing a higher content of bound oxygen in the coating.
'.-.~-,.--~-~.~.-x=,~ ~.~. ~.,.... ~~..~.'-,"~,.s:~=ro~~-~ ~-~- .,.,~...... __-- _.._... ~ ___._ _ .. ._
COMBUSTION ENGINES AND A MI'THOD OF APPL~'fNG SUCH A COATING
This is a divisional of application Serial No. 2,296,155 filed January 17, 2000.
Backaround of the Invention The present invention refers to a ferrous coating applied by a plasma spraying operation to a substrate serving as a cylinder working surface of a combustion engine block. Moreover, the invention also refers to a method of applying a ferrous coating to a substrate serving as a cylinder working surface of a combustion engine block.
Prior Art In the prior art, the traditional material for the working surfaces of the cylinders of combustion engine blocks that are made of aluminum or magnesium alloy is constituted by grey cast iron or cast iron blended with compacted graphite. Thereby, cylinder sleeves made of such cast iron are pressed or cast into these combustion engine blocks.
By providing such cylinder sleeves, however, on the one hand the size and the weight of the engine block is influenced in a negative sense. On the other hand, an in-convenient or adverse connection between the cylinder sleeves made of cast iron end the engine block made of a light metal alloy must be taken into account.
Alternatively, also coatings applied by a galvanising process have been used. However, the applica-tion of such coating is expensive and, moreover, such coatings may corrode under the influence of sulfuric acid and formic acid.
- z -Furthermore, the application of a coating to bores in gene.rat by means of a plasma spraying operation is known in the art for a long time. Thereby, a variety of me-lallic matenais can be applied to the substrate. Once the coating has been applied by means of the plasma spraying operation, the bores are further processed by diamond honing to rEach their desired fnai diameter and provided with the desired topography.
The ability of the coating to be processed and machined, respectively, and the tribologic properties are depending to a high degree on the microstructure and the physical prop-erties of the particular coating.
Objects of the Invention It is an object of the present invention to improve the machining and processing, respectively, as well as the tribotogic properties of ferrous coatings for the working sur-faces of combustion engine cylinder blocks applied by a plasma spraying operation.
z Sumrn_ary of the invention !n order to meet this and other objects, the invention provides, in a first aspect, a ferrous coating applied by a plasma spraying operation to a substrate serving as a cyl-finder working surface of a combustion engine block, whereby the coating has a content of bound oxygen of between 1 % and 4% by weight.
"fhe inventiøn is based on the surprising observation that a microstructure can be created by means of a specially controlled reaction of the powder used far the coating and oxygen during a plasma spraying operation, i.e_ a microstructure comprising out standing properties as far as machining and processing, respectively, as well as tri-boiogy are concerned. Particularly, the coefficient of friction and the tendency towards scuffing, i_e. the beginning of adhesive wear, are drastically decreased.
As previously mentioned, the coating of the invention, applied by plasma spray-ing, has a content of bound oxygen of between 1 and 4% by weight. As a substrate for applying such a coating, particularly suitable are:
~ !he cylinder bores of combustion engine cylindEr blocks made of an aluminum or a mar~nesium alloy or of cast iron;
~ the inner wall of sleeves made of cast iron and inserted into a combustion cn~
give cylinder block made of an aluminum or a magnesium alloy.
In a preferred embodiment, the bound oxygen forms, together with the iron, Fe0 and Fe304 crystals in the coating. Thereby, if is preferred that the content of Fez43 amounts to less than 0.2% by weight. The amount of the formed oxides can be further controlled by mixing the air with nitrogen or oxygen. if the air is replaced by pure oxy-gen, the content of bound oxygen in the coating is reduced by a factor of about two.
. .... _.. .. .,. ~ -_ . ,~ . _ r , .,. ..,r ~ w.~ .a~.~. .,w ..., .
~._w_.~~~m..~ ..~..~m~,~,~."«.-.~-..~: -~-.rt.., _.~.._.. _..._. _ .~.._ In a second aspect, the invention also refers to a method of applying a ferrous . .
coating to a substrate serving as a cylinder working surface of a combustion engine black. The method comprises the steps of providing a plasma spraying apparatus, pro-viding a coating powder constituting the raw material of the coating to be applied, spraying the coating powder by means of the plasma spraying apparatus onto the cylin-der working surface; and either ~ supplying air to the plasma spraying apparatus and spraying the air simuita-neously with the coating powder onto the substrate in an amount of between 200 and.1000 normalized liters per minute; or supplying an oxygen containing gas to the plasma spraying apparatus and spraying the oxygen containing gas simultaneously with the coating powder onto the substrate in an amount of between 40 and 200 normalized titers oxy-gen per minute; or ~ supplying oxygen to the plasma spraying apparatus and spraying the oxygen simultaneously with the coating powder onto the substrate in an amount of between 40 and 200 normalized liters per minute.
The expression "normalized liters per minute" shat) be understood as "liters per minute at an ambient pressure of 1 bar (~ 10' Pa) and a temperature of 20° C. Prefera-bly, the velocity of the gas flow in the interior of the sleeve or cylinder bore amounts to between 7 and 12 m/s during the plasma spraying operation.
in a preferred embodiment, a gas atomized powder is plasma sprayed to the substrate, whereby the powder has the following composition:
C = 0.4 to 1.5°/a by weight ......w._ .~ .~._._". r...~..~ ~.~. .~.~ ..~ ~~_~ ~_ _.~._~~~ ~.~ _~. _.,.
...... __ . . . .. . . ___..~_....~ ~ ~,. ,.~... ......_ ___. r.
Cr ~ 0_2 to 2.5% by weight Mn = O.a2 to 3% by weight i' = O.D1 to 0_ 1 % by weight, if appropriate S = 0.01 t~ 0.2% by weight, if appropriate Fe = difference to 100~/o by weight, in anoti~er preferred ernbadiment, a gas atomized powder is plasma sprayed to the substrate, whereby the powder has the following composition:
C - 0_1 to 0.8°1° by weight Cr = ~( 1 to 18% by weight Mtl = 0.7 to 1 _5% by weight Mo = 0_1 to 5%, by weight S ~ O.D1 to 0.2% by weight, if appropriate P = 0.07 to 0.1 % by weight, if appropriate he = difference to 100% by weight.
The amount of FeQ and Fe~04 in the coating can be influenced by the distribu, lion of the size of thc; particies of the powder. Depending on the coating to be realized, the size of the particles of the powder can be in the region of between 5 to 25 pm, in the rE:gion of between 10 to 40 frm, or in the region of between 15 to f~0 l.rm.
The size of the pertic(es can be determined by means of an optical or an electronic microscope, par-ticularly by means of a scanning microscope, ar according to the laser diffraction mraiiod MICRC~TRAC.' Preferably, a coating powder is used that has been gas atomized by means of argon or nitrogen.
The best results can be obtained if a coating powder is used that is blended with a tribofogic oxide ceramics. Preferably, the oxide ceramics consists of TiOz or A1~03Ti(J~
and/or Afz03Zr02 alloy systems. The portion of the oxide ceramics in the coating pow, der can amount to between 5 and 5D% by weight.
It should be noted That the optimum particle size is selected according to the tri-bologic properties of the coating to be applied and according to the mechanical behavior of the substrate to which the coating has to be applied.
brief Descrit~tion of the Drawin s In the following; some examples of a coating according to the invention will be further described_ In the accompanying drawings:
Fig. 1 shows a diagram illustrating the relation between the particle size of the coating powder and the decrease of the coefficient of friction as welt as the relation be-tween the particle size of the coating powder and the mechanical characteristics, ~par-ticula~iy the adhesive strength of the coating; and Fig. 2 shows a diagrarr~ illustrating the relation between the amount of bound oxygen in the coating and the decrease of the coefficient of friction as welt as the refa-lion between the amount of bound oxygen in the coating and the mechanical character-istics, particularly the adhesive strength of the coating.
Example 1 A coating powder has been applied to the working surface of a cylinder sleeve of a combustion engine by means of a plasmatran. The coating powder had the following composition-C = 9 .1 % by weight .
Cr = i .5°/a by Weight Mn = '( _5% by weight Fe = difference to 900% by weight.
If appropriate, the coating powder may also contain S and P in small amounts (i.e. 0.01 to 0.2% by weight).
TY~e size of the particles of the coating powder was between 5 and 25 lrm. The powder has been manufactured by a gas atomizing process. The velocity of the gas ff~~w Burin c~ the operation of applying the coating was 't t7 rn/s, and the amount of air fed to fhe plasmatron for cooling the coating and for the reaction of the powder was 500 NLIaM (nc~rmaiized liters per minute). This corresponds to about 100 NLPM pure oxy-gen. That amount of air was fed through the body of a plasmatron welt known in the art, e.g. as described in U.S. Patent No. 5,519,183.
The results of the experiments that have been run have shown that the content of oxygen in the applied coating was in the region of 3°/a by weight.
According to a macro structural analysis performed by means of X-rays, the oxygen is bound according to the stoichiometric formulas Fe0 and Fe30~,. Moreover, that analysis has shown that the presonce of Fo203 is below the detectable limit.
The coating having been applied, the cylinder sleeve was further processed by diamond honing. Experiments with a combustion engine provided with such cylinder sleeves have clearly confirmed that the coefficient of friction between the piston rings and the wall of the cylinder sleeve is substantially reduced, as compared to well known cylinder sleeves made of grey cast iron.
Example 2 A, powder was used having the same composition as in Example 1 herein before;, but with a particle size of between 10 and 45 ~tm. Moreover, ail other conditions were identical to the ones described ire Example 1. Thereby, it was found that the content of bound oxygen in the applied coating was in the region of 2% by weight. The other re-sults of an analysis of the coating were the same as explained in connection with Ex-ample 1.
The coating having been applied, the cylinder sleeve was further processed by diamond honing. Experiments with a combustion engine provided with such cylinder sleeves have clearly confirmed that the coefficient of friction between the piston rings and the working surface of the cylinder sleeve again is substantially reduced, as com-pared to well known cylinder Sleeves made of grey cast iron, whereby the reduction of the coefficient of fr7ction is in relation to the amount of bound oxygen.
~xam~Ie~3 Cylinder sleeves that are to lie used with combustion engines operated with sul-phurous fuel ar With methanol, such engines being subject to corrosion when they are operated at temperatures below the dew-point at the given conditions, have been coated, under the same conditions as described in Example 1, with a powder having the following composition:
C = 0_~.°r° by weight Cr = 13.0% by weight Mn ~ 1.5% by weight Mo = 2.0% by weight .,....m __ ....._ .. ~ .1...<."~ ~..~, x..M~.~. ....._._- ...._.
.. c~ ...
Fe = difference to 100°la by weight.
ft appropriate, the coating powder may also contain S and P in small amounts (i.e. 0.01 to 0.2°l° by weight).
The-: size c~f the particles of the coating powder was between 10 and 45 Nm.
The tests that have been run using such a coating yielded substantially the same I~-worabla results as explained in Examples '1 and 2.
Example 4 The same procedure was performed as described in Example: 2, except that 30%
by weictht of an ceramics alloy powder was added to the coating powder, the ceramics alloy powder having a composition of 60°!° by weight AIZO~ and 40% by weight TiQ2.
The coatings created using such a powder are rtfechanicaliy reinforced due to the inclu-lion of the ceramics particles with a size of between ~ and 22 pm.
_ _ n _,.-..~,~,x..~:_~. ~-~:.~~....~~_~_.. ._ __ ._ _.____.____ . _. _ __ _.___-_~_....~.....~___~__.. _ , _ __ - so -Example r ~i'he same procedure was repeated as described in Example 4, except that 30%
by weight of a ceramics alloy powder was added to the coating powder, the ceramics alloy powder having a composition of SO% by weight A1203 and 20% by weight Ti02.
The coatings created using such a powder are mechanically reinforced due to the inclu-sion of the ceramics particles with a size of befween 5 and 22 frm.
Fig. 1 shows a diagram illustrating the relation between the particle size of the coating powder and the decrease of the coefficient of friction as well as the relation be-tween the particle size of the coating. powder and the mechanical characteristics, par-ticularly the adhesive strength of the coating. It Is evident tram the diagram, on the one hand, that the coefficient of friction gets lower if the size of the particles is increased. On the other hand, the adhesive strength is gradually reduced if the particle size is in-creased. A goad compromise may be a particle size in the region of 25 to 30 um, whereby the adhesive strength amounting to appr. 45-50 MPa should be sufficient in most cases while the coefficient of friction is stilt reduced, as compared to the prior art coatings, 6y about 22-25%. However, if adhesive strength is the primary goal and the reduction of the coefficient of friction is but of secondary importance, one would chose a coating powder having particles with a smaller size. In another application, in which the reduction of the coeificient of friction is the primary goa! and the adhesive strength of tile coating is less important, ono would chose a coating powder having particles with a greater size.
Fig. 2 shows a diagram illustrating the relation between the amount of bound oxygen in the coating and decrease of the coefficient of friction as well as the rotation ..
between the amount of bound oxygen in the coating and mechanical characteristics, parCicutariy the adhesive strength of the coating. tt is evident from the diagram, on the orro hand, that the coefficient of friction gets lower if the amount of bound oxygen in the coating is increased. On the other hand, the adhesive strength is reduced if the amount of bound oxygen in the coating is increased. A good compromise may be a content of bound oxycden in the region of between 2-2.5% by weight, whereby the adhesive strength amounting to appr. 40-~t~ MPs should be sufficient in most cases while the co-efficient of friction is still reduced, as compared to the prior art coatings, by about 20-25%: Correspondingly to what is explained in connection with !=ig. 1, i.e. if adhesive strength is the primary goal and the reduction of the coefficient of friction is but of sec-ondary importance, one would strive for realizing a tower content of bound oxygen in the coating. tn another application, in which the reduction of the coefficient of friction is the primary goal and the adhesive strength of the coating is Less important, one would strive for realizing a higher content of bound oxygen in the coating.
'.-.~-,.--~-~.~.-x=,~ ~.~. ~.,.... ~~..~.'-,"~,.s:~=ro~~-~ ~-~- .,.,~...... __-- _.._... ~ ___._ _ .. ._
Claims (14)
1. A spraying powder for coating a substrate, in particular for coating a cylinder bore of a combustion engine block made of an aluminium or a magnesium alloy or of cast iron, or for coating the inner wall of a sleeve made of cast iron, which sleeve can be inserted into a combustion engine cylinder block, and which spraying powder has the following composition:
C = 0.4 to 1.5% per weight Cr = 0.2 to 2.5% per weight Mn = 0.02 to 3% per weight Fe difference to 100% per weight.
C = 0.4 to 1.5% per weight Cr = 0.2 to 2.5% per weight Mn = 0.02 to 3% per weight Fe difference to 100% per weight.
2. A spraying powder for coating a substrate, in particular for coating a cylinder bore of a combustion engine block made of an aluminium or a magnesium alloy or of cast iron, or for coating the inner wall of a sleeve made of cast iron, which sleeve can be inserted into a combustion engine cylinder block, and which spraying powder has the following composition:
C = 0.4 to 1.5% per weight Cr = 0.2 to 2.5% per weight Mn = 0.02 to 3% per weight S = 0.01 to 0.2% per weight P = 0.01 to 0.1% per weight Fe difference to 100% per weight.
C = 0.4 to 1.5% per weight Cr = 0.2 to 2.5% per weight Mn = 0.02 to 3% per weight S = 0.01 to 0.2% per weight P = 0.01 to 0.1% per weight Fe difference to 100% per weight.
3. A spraying powder for coating a substrate, in particular for coating a cylinder bore of a combustion engine block made of an aluminium or a magnesium alloy or of cast iron, or for coating the inner wall of a sleeve made of cast iron, which sleeve can be inserted into a combustion engine cylinder block, and which spraying powder has the following composition:
C = 0.1 to 0.8% per weight Cr = 11 to 18% per weight Mn = 0.1 to 1.5% per weight Mo = 0.1 to 5% per weight Fe difference to 100% per weight.
C = 0.1 to 0.8% per weight Cr = 11 to 18% per weight Mn = 0.1 to 1.5% per weight Mo = 0.1 to 5% per weight Fe difference to 100% per weight.
4. A spraying powder for coating a substrate, in particular for coating a cylinder bore of a combustion engine block made of an aluminum or a magnesium alloy or cast iron, or for coating the inner wall of a sleeve made of cast iron, which sleeve can be inserted into a combustion engine cylinder block, and which spraying powder has the following composition:
C = 0.1 to 0.8% per weight Cr = 11 to 18% per weight Mn = 0.1 to 1.5% per weight Mo = 0.1 to 5% per weight S = 0.01 to 0.2% per weight P = 0.01 to 0.1% per weight Fe difference to 100% per weight.
C = 0.1 to 0.8% per weight Cr = 11 to 18% per weight Mn = 0.1 to 1.5% per weight Mo = 0.1 to 5% per weight S = 0.01 to 0.2% per weight P = 0.01 to 0.1% per weight Fe difference to 100% per weight.
5. A spraying powder according to anyone of the preceding claims, wherein the size of the particles of the powder is in the region of between 5 to 25 µm.
6. A spraying powder according to one of the claims 1 to 4, wherein the size of the particles of the powder is in the region of between 10 to 40 µm.
7. A spraying powder according to one of the claims 1 to 4, wherein the size of the particles of the powder is in the region of between 15 to 60 µm.
8. A spraying powder according to anyone of the preceding claims, which powder has been atomized by means of argon or nitrogen.
9. A spraying powder according to anyone of the preceding claims, which powder has been modified by an addition of a tribologic oxide ceramics.
10. A spraying powder according to claim 9, in which powder the content of said oxide ceramics amounts to between 5 and 50% by weight.
11. A spraying powder according to claim 9, wherein said oxide ceramics consists of TiO2 alloy systems.
12. A spraying powder according to claim 9, wherein said oxide ceramics consists of Al2O3TiO2 alloy systems.
13. A spraying powder according to claim 9, wherein said oxide ceramics consists of Al2O3ZrO2 alloy systems.
14. A spraying powder according to claim 9, wherein said oxide ceramics consists of AlO23TiO2 and Al2O3ZrO2 alloy systems.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002296155A CA2296155C (en) | 1999-01-19 | 2000-01-17 | A coating for the working surface of the cylinders of combustion engines and a method of applying such a coating |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002296155A Division CA2296155C (en) | 1999-01-19 | 2000-01-17 | A coating for the working surface of the cylinders of combustion engines and a method of applying such a coating |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2469461A1 true CA2469461A1 (en) | 2000-07-19 |
Family
ID=32739209
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002469461A Abandoned CA2469461A1 (en) | 2000-01-17 | 2000-01-17 | A coating for the working surface of the cylinders of combustion engines and a method of applying such a coating |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2469461A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113463009A (en) * | 2021-07-21 | 2021-10-01 | 昆明理工大学 | Preparation method of wear-resistant coating on surface of aluminum alloy engine cylinder hole |
| CN113463010A (en) * | 2021-07-21 | 2021-10-01 | 昆明理工大学 | Remanufacturing process for surface of cast iron cylinder hole of internal combustion engine |
-
2000
- 2000-01-17 CA CA002469461A patent/CA2469461A1/en not_active Abandoned
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113463009A (en) * | 2021-07-21 | 2021-10-01 | 昆明理工大学 | Preparation method of wear-resistant coating on surface of aluminum alloy engine cylinder hole |
| CN113463010A (en) * | 2021-07-21 | 2021-10-01 | 昆明理工大学 | Remanufacturing process for surface of cast iron cylinder hole of internal combustion engine |
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