TWI303193B - Powder metallurgical composition comprising carbon black as flow enhancing agent - Google Patents

Abstract

The invention concerns a powder metallurgical composition comprising iron or iron-based powder and a minor amount, I.e. o.001-0.2 wt-%, of carbon black. The carbon black acts as flow enhancing agent.

Description

1303193 IX. Description of the Invention: [Technical Field to Which the Invention Is Ascribed] The present invention relates to a powder metallurgy composition mainly composed of iron. More particularly, the present invention relates to compositions comprising a flow aid which improves fluidity and improves apparent density. [Prior Art] Powder metallurgical compositions for the preparation of powder metallurgical parts are well known. The preparation of the powder metallurgy part comprises filling the powder into a compacting tool, compacting the powder and subsequent sintering steps of the compacted body. The necessary conditions for filling the powder are that the powder has free flow and has sufficient fluidity. The high fluidity of the powder is necessary to achieve high yields, lower manufacturing costs and better economics of the parts produced. Another necessary factor for this preparation efficiency and economy is the visual acuity. The apparent density is necessary for tool settings. Powders with low apparent density require higher fill heights, which can result in non-essentially high press tools, which in turn can result in longer compaction strokes and lower press properties. Agents that improve these flow properties have been previously known. Therefore, U.S. Patent No. 3,357,8 18 discloses the use of a sulphuric acid to achieve this goal. U.S. Patent No. 5,782,954 discloses the use of metals, metal oxides or cerium oxide as a flow aid. It is an object of the present invention to provide powder metallurgical compositions having improved powder properties (e.g., flow and apparent density). SUMMARY OF THE INVENTION It has been unexpectedly found that the powder properties can be improved by adding a small amount of carbon black to an iron-based powder group 103115-970509.doc 1303193. To change ... ^ riding black and controlled addition can maintain or Shi Wenliang the # mechanical properties and powder body strength. [Embodiment] A composition such as a powder containing iron or iron-based powder and a composition for use in such a general composition may also contain a binder, optionally selected as an element, and other alloying elements. Hard phase materials, liquid phase forming materials, and machining enhancers may also be included. The iron-based powder can be any type of iron-based powder, two: 'water atomized iron powder, reduced iron powder, pre-alloyed type iron-based or diffusion alloy type mainly iron Powder. Such powders are, for example, the iron powder ascigg.29, the diffusion alloy type iron-based copper-containing, recorded and turned-over powder Di wall y AB, the iron-based and chromium and key pre-alloyed Powders AStaloy CrM and Astal〇y CrL, all obtained from Hiiganas AB, Sweden. According to the present invention, the carbon content in the iron-based powder composition is between 〇. and 0.2% by weight, preferably between 〇〇1 and 〇% by weight. The original particle size of the carbon black is preferably 2 nm or less, more preferably less than 10 nm, and most preferably 50 nm or less. In a preferred embodiment, the specific surface area is determined by the BET method to be between 15 Å and 2 meters. However, other types of carbon blacks having other surface areas and original particle sizes can be used. Carbon black is generally used as a filler in a rubber material, and as a color pigment. Due to its conductivity, it can also be used in products to reduce static electricity. U.S. Patent No. M02,315 discloses a combination of carbon black and iron or iron-based powder 103115-970509.doc 1303193. ^ t — Μ 利 揭示 reveals a mixture of compounds, in which the alloy is combined with a powder such as a powder, such as a correction, and a metal, and a carbon black is added thereto by a binder. U.S. Patent No. 6 '2, 3 15 does not disclose any content of carbon black, large particles/J, or (4 乍, 曰 / /, only related to the bonding material. Patent application jp 7 _, also disclosed A carbon black-free powder composition. Here, the function of carbon black is to deoxidize the base material. The compositions according to the present invention may also comprise a material selected from the group consisting of graphite, steel, recordings, 1 Meng, Shi Xi, hunger, An alloying element of a group consisting of platinum, phosphorus, crane, sulfur, and sharp. For the compression of a strong powder and accelerating the injection of the powder body component, a lubricant or a combination of different lubricants may be added to The slip agent in the powder metallurgical composition may be present in the form of a particulate powder or adhered to the surface of the iron-based powder. By adding a binder which has been dissolved in the solvent, the lubricant may be The iron-based powder 2 = δ ° may also be added in the form of its binder, which acts to form a film around the iron-based powder. Another lubricant may be used as a lubricant. The gentleman w' goes to use the moon piece J 乂 as a binder, which is The melting point of the slip agent is heated to a temperature of at least one of the lubricants, the temperature or at least one of the lubricant components, and then the melting degree of the group. The order is below the melting point The temperature of these lubricants may be selected from the free fatty acid ethylenediamine (for the benefit of fatty acids or other derivatives of fatty acids: for example, 'double hard fat brewing, taking & - biological (for example, metal stearic acid, polyolefin (for example, poly Ethylene, an alcohol, a guanamine polymerizes a group consisting of your ruthenium oligo oligo. The granules are preferably selected from the group consisting of polysaccharide, 103115-970509.doc 1303193 a group consisting of amine wax, a guanamine polymer or a guanamine oligomer. The binders are selected from the group consisting of cellulose ester resins, high knives thermoplastic phenolic resins, hydroxyalkyl fibers. The resin is preferably selected from the group consisting of cellulose ester resins and hydroxyalkyl cellulose resins. The possible additives are mechanical process improvers, hard phase materials and liquid phase formers. According to a preferred embodiment, the adhesive is bonded The compound (i.e., a mixture in which finer powder particles are bonded to the surface of the iron or iron-based powder particles by a binder, because these mixtures generally have poor flow properties) is used as a glidant. When used in a bonded mixture, it is preferred to add carbon black after the bonding operation has been performed. The bonding operation is carried out by mixing the mixture to a temperature above the melting point of the crucible at a mixing period of $ Then, the mixture is cooled until the binder [curing m is added to the binder which has been dissolved in the solvent. In this case, the bonding operation can be completed by heating or vacuum to evaporate the solvent. The composition is pressed. And sintering to obtain the final powder metal part. The invention can be further illustrated by the following non-limiting examples. Example 1 -,,,,,,,,,,,,,,,,,,,,, . The particle size can be determined by electron selection using three kinds of carbon black having different specific surface areas and particle sizes according to Table 1, and it refers to the original of the carbon black (four) micrograph 103115-970509.doc 1303193

Table 1 Type specific surface area (m 2 / gram) Original particle size (nano) CBl^ 1000 30 CB2^ 250 18 CB3* 150 23 ★ Degussa AG from Germany made iron-based powder 8 (: 100.29 ( Available from Sweden 1108 & 11 & 8 8 3) with 0.77 wt% graphite, 0.8% binder/lubricant system (from 0.2% polyethylene (Polywax 650) and 0.6% distequine ethylenediamine (EBS) The mixture was heated to a temperature above the melting point of Polywax and then cooled. At a temperature below the melting point of Polywax, 0.03% carbon black was added. The three carbon black types according to Table 1 were tested. Two mixtures were prepared as a reference mixture. Reference mixture C was prepared according to the test mixtures except for 0.8% graphite and no added flow aid. In reference mixture R, 0.8% graphite and 0.06% were obtained from Degussa AG. The properties of the powder were determined by Aerosil® A-200. The flow properties were determined using this standard method (Hall-flow cup according to ISO 4490) and the apparent density (AD) was determined using standard method ISO 3923. The results are shown in Table 2. Table 2 ID powder composition logistics rate 粆 / 50 g) AD ~ ~ (g / cm3) C ASC100.29 + 0.8% carbon + 0.8% lubricant 30.0 3.06 R ASC100.29 + 0.8% carbon + 0.8% lubricant + 0.06% A-200 25.4 3.11 ----- CB1 ASC100.29 + 0.77% carbon + 0.8% lubricant + 〇·〇3 CB1 "23^0 3.29 CB2 ASC 100.29 + 0.77% carbon + 0.8% lubricant + 〇.〇3 CB2 26.4 3.15 CB3 ASC 100.29 + 0.77% carbon + 0.8% lubricant + 〇·〇3 CB3 25.8 3.14 103115-970509.doc 1303193 These tests show that compared to mixtures without any glidant, add The carbon black to powder metallurgical mixture improves the flow rate and AD. Compared with the addition of known flow aids, the addition of CB 1 improved the flow rate and AD. However, the addition of CB2 and CB3 resulted in approximately the same flow rate improvement and higher AD compared with the addition of the flow aid A-200. Example 2 A carbon black type CB 1 was selected to determine the optimum amount of the iron-based powder mixture to be added. The mixtures were prepared according to the description of Example 1. The amounts of elements, binders/lubricants, glidants and graphite added to the alloy are shown in Table 3. A reference mixture R1 containing no glidant and a reference mixture R2 having a commercially available glidant (which is Aerosil® A_200 from Degussa AG) were prepared. Table 3 ID powder composition logistics rate (seconds / 50 grams) AD (g / cm3) B1 ASC100.29 + 2% copper + 0.8% carbon + 0.8% lubricant + 0.025% CB1 20.9 3.48 B2 ASC100.29 + 2% Copper + 0.8% Carbon + 0.8% Lubricant + 0.03% CB1 20.8 3.49 B3 ASC 100.29 + 2% Copper + 0.8% Carbon + 0.8% Lubricant + 0.04% CB1 21.1 3.46 B4 ASC 100.29 + 2% Copper + 0.8°/. Carbon + 0.8% Lubricant + 0.06% CB1 21.6 3.43 R1 ASC 100.29 + 2% Copper + 0.8% Carbon + 0.8% Lubricant 29.6 3.19 R2 ASC 100.29 + 2% Copper + 0.8% Carbon + 0.8% Lubricant + 0.06% A -200 24.5 3.28 Compact the test part according to ISO 2740 at ambient temperature and sinter at 1120 °C in a 90/10 N2/H2 atmosphere. In Table 4, the mechanical properties of the powder composition according to Table 3 are provided. 103115-970509.doc -10- 1303193 Table 4 ID TS(MPa) YS(MPa) A(%) B1 610 444 2.12 B2 603 442 1.98 B3 596 438 1.93 B4 536 411 1.49 R1 603 437 2.22 R2 545 397 1.93 As can be seen from Table 4, 0.06% of the added amount of carbon black affects tensile strength, TS, lodging strength, YS, and elongation (A). When 0.04% by weight and a better content of carbon black are added, the influence on these mechanical properties is negligible. Example 3 Example 3 shows that the new glidant can be used in the composition for warm compaction. A test mixture (Β5) and a reference mixture (R3) of 3000 g each were prepared as follows. For the reference mixture, thoroughly mix 60 grams of copper powder, 24 grams of graphite, 13.5 grams of high temperature lubricant Promold® (available from Morton International of Cincinnati, Ohio, USA) and the rest of the iron powder (ASC 100.) during heating to 45 °C. 29). Further, 4.5 g of a cellulose ester resin which had been dissolved in acetone was added, and the mixture was mixed, and it took 5 minutes. The material was evaporated at a temperature of 45 ° C during the second mixing period of 10 to 30 minutes to evaporate the solvent. Finally, 1.8 μg of Aei OsiPA-200 was added as a glidant and thoroughly mixed. For the test mixture, thoroughly mix 60 grams of copper powder, 23.1 grams of graphite, 13.5 grams of high temperature lubricant Promold, from Morton International of Cincinnati, Ohio, USA, and the rest of the iron 103115-970509.doc during heating to 45 °C. -11 - 1303193 Powder (ASC 100.29). Further, 45 g of the cellulose ester resin which had been dissolved in acetone was added, and the mixture was mixed, and it took 5 minutes. The material was maintained at a temperature of 45 to evaporate the solvent during the first mixing period of 10 to 30 minutes. Finally, 9 g of carbon black CB1 was added as a glidant and thoroughly mixed. The flow rate and AD of the two mixtures were determined according to ASTM B 213 at a temperature of 120 °C. As can be seen in Table 5, a 'AD' can be increased by a large amount with respect to the powder mixture of the present invention, and the flow rate of the composition containing the new flow aid is substantially the same as compared with the composition containing the known flow aid. Table 5 ID flow rate (seconds / 5 grams) AD (g / cm 勹 R3 " 2L3 "" Ϊ 25 '' B5 ~ 2Z0 ' T35 " -- Example 4 Example 4 shows that the new glidant can be used In a combination of powders having different iron-based powders, the mixtures can be prepared according to the method of Example ,, and the same binder/lubricant system as in Example 1 is used. The iron-based powder and additives are used. The quantities are shown in Table 6. The identifications, ΚΑ, RB, RC, RE and RF indicate that the mixtures are 〇〇 6% gliding agent

Reference mixture of Aerosil A-200 (available from DegUssa AG). These identifications, C, E, and F indicate that the mixtures are in the mixture of all mixtures without any flow aid. The iron or iron-based powder used was as follows: ASC 100.29 - atomized ordinary iron powder from H5ganaSAB.

Distaloy AB - a diffusion of steel, nickel and molybdenum from H6ganas AB 103115-970509.doc -12- 1303193 Gold type iron-based powder.

Astaloy CrM • Pre-alloyed iron-based powder from chrome and molybdenum from H5ganas AB.

Astaloy CrL - a pre-alloyed iron-based powder from C0ganas AB containing chromium and molybdenum. Table 6 ID Powder Mixture Composition RA ASC100.29 + 2% Copper Powder + 〇 · 8% Graphite + 0.8% Lubricant + 0.06% A-200 A1 ASC100.29 + 2% Copper Powder + 〇·77% Graphite + 0 · 8 ° /. Lubricant + 0.03% CB1 RB Dist AE + 0.8% graphite + 0.8% lubricant + 0.06% A-200 B1 Dist AE + 0.77% graphite + 0.8% lubricant + 0.03% CB1 C ASC 100.29 + 0·8% Carbon + 0.8% Lubricant RC ASC 100.29+0.8% Carbon + 〇·8% Lubricant + 0.06% A-200 Cl ASC 100·29 + 0.77% Carbon + 0.8% Lubricant + 0.03% CB 1 E AstCrM+0.4% Carbon + 0.8% lubricant RE Ast.CrM+0.37% Carbon + 0.8% lubricant + 0.06% A-200 El AstCrM+0.37% carbon + 0.8% lubricant + 0.03% CB 1 F AstCrL + 0··6% carbon + 0.8% Lubricant RF Ast.CrL + 0.57% Carbon + 0.8% Lubricant + 0.06% A-200 R1 AstCrL + 0.57% Carbon + 0.8% Lubricant + 0.03% CB 1 The powder properties of the powder mixtures were determined. The test piece according to ISO 2740 was compacted at ambient temperature and sintered at 90 °C N2/H2 at 1120 °C. Mechanical properties such as powder body strength (GS), dimensional change (DC), and sintered density (SD) were measured, and the results are shown in Table 7. 103115-970509.doc -13 - < S ), 1303193 Table 7 ID flow rate (seconds / 50 grams) GS (million kPa) DC% SD [g / cm3] RA 24.8 11.3 0.18 7.01 A1 22.6 ^35 12.8 0.18 7.04 RB 24.8 ΤΪ7 12.3 "-0.15 7.12 B1 23.1 "Ϊ43 '~~ 13.3 -0.15 7.13 C 30 RC 25.4 ΤΓϊ~~~~ 11.6 -0.03 Ύόβ ' Cl 23.0 Τ29 12.6 -0.00 "7Ό7 ' E 31.9 " 2^82~ RE 27.5 Τ93 13.8 -0.25 "6^94 '~~ El Τ' 23.9 Τ〇8~' 16 -0.24 F TIT? 33.1 "Ϊ78 Kr T7 1 28.4 2.88 12.2 -0.13 ^99~~- - r 1 26.5 2.96 14.6 -0.11 ^99 Table 7 shows that carbon black improves the flow rate, AD and powder body strength of mixtures with different base powders compared to mixtures containing known flow aids. Example 5 Example 5 shows The new flow aid can also improve the flow rate of the Yitong mixture (non-adhesive mixture) without any binder. Prepare three kinds of iron-containing powder ASC 100.29 according to Table 8, 2% copper powder, 0.5% graphite, 0.8% A mixture of distearyl acetophenone (as a lubricant) and varying amounts of carbon black (CB 1). Use a mixture that does not contain any carbon black for reference. Mixture. Determine the flow rate of ~+ with the mixture. Table 8 ID CB1 (%) Flow rate (seconds) Reference mixture 0 34.2 1 '' 0.06 31.0 ~ι " 0.08 30.3 As shown in Table 8, add carbon black to non-adhesive Mixture > ώ > a J (文良 The flow rate 0 103115-970509.doc -14-

Claims (1)

1303193 X. Patent application scope: l A powder metallurgical composition containing iron or iron-based metal powder, lubricant and/or binder, and slave black, wherein the carbon black content is between 0.2 and 0.2 Between 篁%, and the particle size of the carbon black is below (10) nm and the specific surface area is above HK) m~g, thereby increasing the fluidity of the powder smelting composition. 2. The powder metallurgical composition of claim 1 wherein the carbon black is present in an amount between 1 and 0.1% by weight. 3. If π is the item! A powder metallurgy composition wherein the carbon black has a particle size of less than 5 nanometers. 4. A powder metallurgy composition according to the invention, wherein the carbon black has a specific surface area of 150 m 2 /g or more. 5. The powder metallurgical composition of the request, wherein the carbon black has a specific surface area of 200 m 2 /g or more. 6. The powder metallurgy composition according to any one of the preceding claims, comprising an additive selected from the group consisting of an element for an alloy, a machinability improver, a hard phase material, and a liquid phase forming agent. 7. The powder metallurgy composition of claim 6, wherein the elements of the alloy are selected from the group consisting of graphite, copper, nickel, chromium, manganese, cerium, vanadium, molybdenum, phosphorus, tungsten, sulfur and cerium. group. 8. The powder metallurgy composition according to claim 7, wherein the alloying elements selected from the group consisting of graphite and steel are combined with the iron or iron-based powder. 9. A carbon black as a flow enhancer for iron-based powder compositions 103115-970509.doc 1303193. Ίο. 11. 12. 13. A method of increasing the flowability of a powder metallurgical composition comprising iron or iron-based metal powders, lubricants and/or binders, the method comprising adding carbon black to the powder metallurgical combination The content of the carbon black is between 0.001 and 0.2% by weight, and the carbon black has a particle size of less than 1 nm and a specific surface area of 100 m 2 /g or more. The method of claim H), wherein the carbon black has a specific surface area of 15 mil 2 /g or more. The method of claim 1G, wherein the specific surface area of the carbon black is 200 m 2 /g, as in any one of the claims 10 to 12, the method of the middle member, comprising a group selected from the group consisting of alloys, Additives for the improvement agent, hard phase material and liquid phase forming agent. 103115-970509.doc