JP2007131937A - Co ALLOY POWDER FOR THERMAL SPRAYING AND COMPOSITE MATERIAL FOR LEAD-FREE SOLDERING EQUIPMENT OBTAINED BY THERMAL SPRAYING OF THE Co ALLOY POWDER - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a Co alloy powder for thermal spraying intended for forming a Co alloy-sprayed layer which is excellent in resistance to corrosion by lead-free solder, especially lead-free Sn-Ag solder in a molten state. <P>SOLUTION: The Co alloy powder for thermal spraying has a composition which contains 20.0-35.0% Cr, 0.1-40.0% Fe, 0.05-1.20% C, 0.5-2.0% Mn, 0.1-3.0% Si, 0.001-0.3% B and, if required, at least one chosen from (a) 3.0-15.0% W, (b) at least one chosen from 0.01-0.15% La and 0.01-0.15% Ce and (c) 0.001-0.05% Mg and the balance being Co and unavoidable impurities. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a Co-based alloy powder for thermal spraying capable of obtaining a Co-based alloy sprayed layer excellent in erosion resistance against molten lead-free solder, in particular, a Sn-Ag solder in a molten state. The present invention relates to a composite member for a lead-free soldering device having a Co-based alloy sprayed layer obtained by spraying a Co-based alloy powder, and further a solder bath, a nozzle, a propeller in the lead-free soldering device comprising the composite member, The present invention relates to a lead-free soldering device component such as a shaft.

Generally, SUS304 (Cr: 18 to 20% by mass, Ni: 8 to 10.5% by mass, balance: Fe and inevitable impurities), SUS309S (Cr: 22 to 24% by mass, Ni: 12) as a material for the lead soldering apparatus SUS316 (Cr: 16-18 mass%, Ni: 10-14 mass%, Mo: 2-3 mass%, balance: Fe and inevitable impurities), etc. Was used.
In recent years, interest in environmental issues has increased, and in Europe, for example, it has been decided to regulate the inclusion of harmful substances in electronic devices. Lead is one of the regulated substances. Therefore, the use of lead solder containing lead as a main component is regulated, and Sn-Ag lead-free solder that does not use lead at all (Sn-3.5% Ag as the composition of Sn-Ag solder that is lead-free solder). Sn-3.0% Ag-0.1% Cu etc. are known) and replacement with conventional lead solder is progressing. Therefore, at present, the Sn-Ag solder is generally shown for lead-free solder.
However, the Sn-Ag solder, which is a lead-free solder, has a higher reactivity and a higher melting temperature than conventional lead solder, and is therefore made of stainless steel such as SUS304, SUS309S, and SUS316. The produced soldering device cannot withstand the erosion of molten lead-free solder. Therefore, the conventional soldering device made of stainless steel is damaged and reaches the service life in a short period of time, and the soldering device must be replaced early. It has become clear that

Here, erosion of stainless steel by molten Sn-Ag solder that is molten lead-free solder will be described. In general, a non-reactive substance such as an oxide film called a passive film is formed on the surface of stainless steel, and the molten Sn-Ag solder contacts the metal surface directly by the non-reactive substance such as the oxide film. Prevent and avoid damage. However, when the surface film disappears due to convection of the molten metal during use, the molten Sn—Ag solder and the metal directly react with each other, causing damage. That is, when a metal such as Fe or Ni having a high melting point reacts with Sn having a low melting point at a temperature lower than the melting point, Sn, which is a low melting point metal, diffuses into the solid, such as Fe or Ni, which has a high melting point, and Sn and As the reaction product is formed and the Sn content of the reaction product increases, the melting point decreases and eventually melts into the molten metal causing damage.
Therefore, in order to alleviate the damage of the soldering device against lead-free solder, the molten lead-free solder of the device is coated by ceramic coating the surface of the stainless steel that constitutes the soldering device or by providing a nitride layer on the stainless steel surface. (See Non-Patent Document 1, Non-Patent Document 2, Non-Patent Document 3, Non-Patent Document 4, etc.).
NIKKEI ELECTRONICS 2003.9.1 pages 49-52 NiKKEI ELECTRONICS 2004.1.5 pp. 91-98 NIKKEI ELECTRONICS 2004.2.2, page 37 NIKKEI ELECTRONICS 2004.2.16 page 35

  However, the ceramic coating may be peeled off due to insufficient adhesion to a stainless steel substrate such as SUS, and the stainless steel substrate may be eroded from the peeled portion. The nitrided layer obtained by nitriding the surface of stainless steel such as SUS is not sufficiently erosion resistant to lead-free solder, and when used for a long time, the nitrided layer loses its thickness and disappears, and the nitrided layer disappears Since the stainless steel base material is eroded from the damaged portion, there is a problem that the erosion resistance against lead-free solder is not sufficient, and the reliability with respect to the erosion resistance is still insufficient. Therefore, there has been a demand for a surface treatment method having a higher erosion resistance against molten lead-free solder for a longer period of time than a surface treatment such as ceramic coating or nitriding treatment.

  Therefore, the present inventor has conducted intensive research to develop a surface treatment method having higher erosion resistance against molten lead-free solder than surface treatment such as ceramic coating or nitriding treatment.

As a result, focusing on the fact that the solid solubility limit of Co to Sn is much smaller than that of Ni and Fe, and by optimizing various additive elements, Cr having excellent erosion resistance against molten lead-free solder: 20. 0 to 35.0% (% represents mass%, hereinafter the same), Fe: 0.1 to 40.0%, C: 0.05 to 1.20%, Mn: 0.5 to 2.0 %, Si: 0.1 to 3.0%, B: 0.001 to 0.3%, and if necessary, one or more of the following (a) to (c) The Co-based alloy sprayed layer obtained by spraying a Co-based alloy powder having a composition consisting of Co and unavoidable impurities on the surface of stainless steel has the same component composition as the Co-based alloy powder, This Co-based alloy sprayed layer is extremely excellent in erosion resistance against molten lead-free solder. The adhesion to the stainless steel substrate is much better than the ceramic coating, so it can prevent erosion due to the peeling of the ceramic coating as mentioned above, and more resistant to molten lead-free solder than the nitride layer. We obtained the knowledge that the erosion resistance is even better, and it can be formed on the surface of a stainless steel substrate thicker than the nitride layer, so that it does not impair the reliability of erosion resistance even if it is used for a long time. It is. However, said (a)-(c)
(A) W: 3.0 to 15.0%,
(B) one or two of La: 0.01 to 0.15% and Ce: 0.01 to 0.15%;
(C) Mg: 0.001 to 0.05%.

This invention has been made based on such knowledge,
(1) By mass%, Cr: 20.0-35.0%, Fe: 0.1-40.0%, C: 0.05-1.20%, Mn: 0.5-2.0% Co-based alloy powder for thermal spraying containing Si: 0.1 to 3.0%, B: 0.001 to 0.3%, and the balance consisting of Co and inevitable impurities,
(2) By mass%, Cr: 20.0-35.0%, Fe: 0.1-40.0%, C: 0.05-1.20%, Mn: 0.5-2.0% , Si: 0.1 to 3.0%, B: 0.001 to 0.3%, W: 3.0 to 15.0%, with the balance being Co and inevitable impurities Co-based alloy powder for thermal spraying,
(3) By mass%, Cr: 20.0-35.0%, Fe: 0.1-40.0%, C: 0.05-1.20%, Mn: 0.5-2.0% , Si: 0.1 to 3.0%, B: 0.001 to 0.3%, and La: 0.01 to 0.15% and Ce: 0.01 to 0.15% A Co-based alloy powder for thermal spraying containing one or two of the following, with the balance being Co and inevitable impurities,
(4) By mass%, Cr: 20.0-35.0%, Fe: 0.1-40.0%, C: 0.05-1.20%, Mn: 0.5-2.0% , Si: 0.1 to 3.0%, B: 0.001 to 0.3%, further Mg: 0.001 to 0.05%, the balance consisting of Co and inevitable impurities Co-based alloy powder for thermal spraying,
(5) By mass%, Cr: 20.0-35.0%, Fe: 0.1-40.0%, C: 0.05-1.20%, Mn: 0.5-2.0% , Si: 0.1 to 3.0%, B: 0.001 to 0.3%, W: 3.0 to 15.0%, and La: 0.01 to 0. Co-based alloy powder for thermal spraying containing 15% and Ce: one or two of 0.01 to 0.15%, the balance being composed of Co and inevitable impurities,
(6) By mass%, Cr: 20.0-35.0%, Fe: 0.1-40.0%, C: 0.05-1.20%, Mn: 0.5-2.0% , Si: 0.1 to 3.0%, B: 0.001 to 0.3%, W: 3.0 to 15.0%, and Mg: 0.001 to 0. Co-based alloy powder for thermal spraying having a composition containing 05% and the balance consisting of Co and inevitable impurities,
(7) By mass%, Cr: 20.0-35.0%, Fe: 0.1-40.0%, C: 0.05-1.20%, Mn: 0.5-2.0% , Si: 0.1 to 3.0%, B: 0.001 to 0.3%, and La: 0.01 to 0.15% and Ce: 0.01 to 0.15% A Co-based alloy powder for thermal spraying, containing Mg: 0.001 to 0.05%, and the balance comprising Co and inevitable impurities,
(8) By mass%, Cr: 20.0-35.0%, Fe: 0.1-40.0%, C: 0.05-1.20%, Mn: 0.5-2.0% , Si: 0.1 to 3.0%, B: 0.001 to 0.3%, W: 3.0 to 15.0%, and La: 0.01 to 0. 15% and Ce: containing one or two of 0.01 to 0.15%, further containing Mg: 0.001 to 0.05%, the balance consisting of Co and inevitable impurities Co-based alloy powder for thermal spraying,
(9) For erosion resistance to molten lead-free solder having the component composition described in (1), (2), (3), (4), (5), (6), (7) or (8) It is characterized by an excellent Co-based alloy sprayed layer.

Thermally spraying a Co-based alloy powder for thermal spraying having the component composition described in (1), (2), (3), (4), (5), (6), (7) or (8) of this invention. The resulting Co-based alloy sprayed layer is excellent in corrosion resistance against molten lead-free solder, and composite materials obtained by forming this Co-based alloy sprayed layer on a substrate such as stainless steel are lead-free soldered. This composite member is effective as a member of equipment, and as a member of various components of lead-free soldering equipment such as solder tanks, injection nozzles, propellers, shafts, ducts, heater protection tubes, and heater cladding tubes in lead-free soldering equipment. It is valid. Therefore, the present invention
(10) A composite member for a lead-free soldering device in which a Co-based alloy sprayed layer having excellent erosion resistance against the molten lead-free solder described in (9) is formed on a base material,
(11) A solder bath for a lead-free soldering device comprising the composite member for a lead-free soldering device according to (10),
(12) An injection nozzle for a lead-free soldering device comprising the composite member for a lead-free soldering device according to (10),
(13) A propeller for a lead-free soldering device comprising the composite member for a lead-free soldering device according to (10),
(14) A shaft for a lead-free soldering device comprising the composite member for a lead-free soldering device according to (10),
(15) A lead-free soldering device duct comprising the composite member for a lead-free soldering device according to (10),
(16) A heater protective tube for a lead-free soldering device comprising the composite member for a lead-free soldering device according to (10),
(17) A heater-coated tube for a lead-free soldering device comprising the composite member for a lead-free soldering device according to (10).

Next, the reason for limitation of each element in the alloy composition of the Co-based alloy powder for thermal spraying and the Co-based alloy sprayed layer according to the present invention will be described in detail.
Cr:
Cr is concentrated on the surface to form a thin and dense passive film mainly composed of Cr ₂ O ₃ , so that the molten Sn-Ag solder, which is a molten lead-free solder, directly contacts the Co-based alloy sprayed layer. However, if Cr is contained in an amount of less than 20.0%, a desired effect cannot be obtained. This is not preferable because the adhesive strength of the resin is reduced. Therefore, Cr contained in the Co-based alloy powder for thermal spraying and the Co-based alloy sprayed layer of the present invention was set to 20.0 to 35.0%. More preferably, it is 21.0-25.0%.

Fe:
Fe is added because it has the effect of improving the adhesion between the sprayed layer and the substrate. However, even if Fe is contained in an amount of less than 0.1%, the desired effect cannot be obtained, whereas it exceeds 40.0%. If contained, the corrosion resistance against lead-free solder deteriorates, which is not preferable. Therefore, the content of Fe is set to 0.1 to 40.0%. More preferably, it is 1 to 20%.

C:
C forms Cr carbide, which is a hardened phase, together with Cr contained at the same time, and finely disperses this in the substrate to significantly improve the wear resistance and remarkably improve the erosion resistance against the flowing molten lead-free solder. Although the desired effect is not obtained even if C is contained less than 0.05%, on the other hand, if it exceeds 1.20%, the sprayed layer becomes brittle and peels due to vibration during use. Since it becomes easy to do, it is not preferable. Therefore, the content of C is set to 0.05 to 1.20%. A more preferable range is 0.06 to 0.2%.

Mn:
Mn stabilizes the austenite structure which is the crystal structure of the parent phase, thereby suppressing the embrittlement of the sprayed layer and, as a result, has an effect of improving the adhesion to the base material. If less than 2.0%, the desired effect cannot be obtained. On the other hand, if it exceeds 2.0%, the wettability with lead-free solder is increased and the reaction with molten lead-free solder is promoted, thereby accelerating damage. This is not preferable. Therefore, the Mn content is set to 0.5 to 2.0% (more preferably 0.5 to 1.5%).

Si:
Since Si has a high affinity with oxygen, SiO ₂ is formed on the surface, and the Sn—Ag alloy, which is a molten lead-free solder, together with Cr ₂ O ₃ has an effect of inhibiting the direct contact with the metal and reacting. However, even if Si is contained in less than 0.1%, the desired effect cannot be obtained. On the other hand, if it exceeds 3.0%, embrittlement of the alloy becomes obvious, and the adhesion to the substrate decreases. This is not preferable. Therefore, the Si content is set to 0.1 to 3.0%. A more preferable range is 0.5 to 2.0%.

B:
B is added because it has the effect of improving the toughness of the sprayed layer and the adhesion to the substrate, but if its content is less than 0.001%, the desired effect cannot be obtained, while it exceeds 0.5%. On the other hand, the toughness of the sprayed layer and the adhesion to the base material are lowered, which is not preferable. Therefore, the content of B is set to 0.001 to 0.5%. A more preferable range is 0.01 to 0.2%.

W:
W is added as needed because it improves the wear resistance by forming C and WC and has the effect of suppressing damage caused by molten lead-free solder. However, W is added in an amount of less than 3.0%. However, the desired effect cannot be obtained. On the other hand, if the content exceeds 15.0%, the effect of Cr is remarkably impaired, and as a result, the erosion resistance against lead-free solder is lowered. Therefore, the content of W is set to 3.0 to 15.0%. A more preferable range is 13.0 to 15.0%.

La and Ce:
These components can be added in trace amounts to improve the erosion resistance of molten lead-free solder by improving the adhesion of the surface film formed in the molten lead-free solder. Added. However, if the content of La is less than 0.01%, the desired effect cannot be obtained. On the other hand, if the content exceeds 0.15%, the surface film tends to peel off and becomes harmful, which is not preferable. Therefore, the content of La is set to 0.01 to 0.15%. A more preferable range of the La content is 0.05 to 0.12%.
Similarly, if the Ce content is less than 0.01%, a sufficient effect for improving the adhesion of the surface film cannot be obtained. On the other hand, if the Ce content exceeds 0.15%, the surface film peels off. Since it becomes easy and harmful, it is not preferable. Therefore, the Ce content is determined to be 0.01 to 0.15%. A more preferable range of the Ce content is 0.05 to 0.12%.

Mg:
When Mg coexists with Mn, it stabilizes the austenite structure which is the crystal structure of the parent phase, thereby suppressing embrittlement and imparting the toughness of the sprayed layer, thereby improving the adhesion to the substrate. However, if the Mg content is less than 0.001%, the desired effect is not exhibited. On the other hand, if the Mg content exceeds 0.05%, lead stability is deteriorated and lead is deteriorated. Since erosion resistance in free solder is deteriorated, it is not preferable. Therefore, the Mg content is set to 0.001 to 0.05% (more preferably 0.002% to 0.010%).

Inevitable impurities:
Inevitable impurities include P and S. These impurities are preferably reduced as much as possible. Further, Ni is contained when using Co raw material impurities and scrap raw materials, but it is acceptable if the content is less than 5%.

  The thermal spray layer obtained by thermal spraying the Co-based alloy powder for thermal spraying according to the present invention is excellent in erosion resistance against lead-free solder and has excellent adhesion to the base material. It can be used without being damaged for a long period of time, and has excellent effects on the electronic and electrical industries.

A Co-based alloy melt obtained by melting and casting using a normal high-frequency melting furnace is pulverized by a normal gas atomizing method to have the component composition shown in Tables 1 to 4 and an average particle size of 40 to 100 μm. The Co-based alloy powders for thermal spraying of the present invention (hereinafter referred to as powders for thermal spraying) 1 to 32 and the Co-based alloy powders for thermal spraying of comparative inventions (hereinafter referred to as powders for comparative thermal spraying) 1 to 17 are prepared. Prepared.
Further, a ceramic powder for thermal spraying made of commercially available alumina was purchased and prepared as a conventional thermal spraying powder.
Further, a stainless steel plate having a thickness of 3 mm made of SUS304 is prepared, and the surface of the stainless steel plate is pretreated by blasting with alumina grid # 20. The pretreated stainless steel plate is 5 mm in length and 50 mm in width. A stainless steel substrate was prepared by cutting so as to have dimensions.
Furthermore, a lead-free solder having a composition of Sn-3.2% Ag-0.1% Cu, which is known as a basic composition of lead-free solder, was prepared.

  The present invention thermal spraying powders 1 to 32, comparative thermal spraying powders 1 to 17 and the conventional thermal spraying powder are prepared on the surface of the stainless steel substrate previously prepared by the usual plasma spraying method: 0.4 mm A thermal spray layer was formed to prepare a composite plate.

Further, a lead-free solder having a composition of Sn-3.2% Ag-0.1% Cu was heated to 430 ° C. and maintained at this temperature to produce a molten lead-free solder. The molten lead-free solder was convected by a stirring blade, and the composite plate was immersed in the convected molten lead-free solder and held for 1000 hours. After holding for 1000 hours, the composite plate is taken out and externally observed to observe the presence or absence of thermal spray layer peeling. The results are shown in Tables 1 to 4, and the surface of the composite plate without thermal spray layer peeling is observed with an optical microscope. The maximum erosion depth was measured, and the results are shown in Tables 1 to 4, and the erosion resistance against molten lead-free solder was evaluated.

From the results shown in Tables 1-4,
(B) A ceramic sprayed layer produced using a conventional thermal spraying powder peels off when immersed in a convection molten lead-free solder for a long time, but a thermal sprayed layer produced using the present thermal spraying powders 1 to 32 is There is no exfoliation and the adhesion to the stainless steel substrate is remarkably excellent.
(B) The thermal spray layer produced using the thermal spraying powders 1 to 32 of the present invention does not peel and the maximum erosion depth is small, but the thermal spraying produced by the comparative thermal spraying powders 1 to 17 outside the scope of the present invention. It can be seen that some of the layers peel off, and even when they do not peel off, the maximum erosion depth is remarkably increased and the reliability against erosion resistance is low.
In addition, although tested about the sprayed layer in the Example, the same result was obtained also about the build-up layer formed using the Co-based alloy powder for thermal spraying of this invention.

Claims (17)

In mass%, Cr: 20.0-35.0%, Fe: 0.1-40.0%, C: 0.05-1.20%, Mn: 0.5-2.0%, Si: A Co-based alloy powder for thermal spraying comprising 0.1 to 3.0%, B: 0.001 to 0.3%, and the balance being composed of Co and inevitable impurities. In mass%, Cr: 20.0-35.0%, Fe: 0.1-40.0%, C: 0.05-1.20%, Mn: 0.5-2.0%, Si: It contains 0.1 to 3.0%, B: 0.001 to 0.3%, further contains W: 3.0 to 15.0%, and the balance is composed of Co and inevitable impurities. Co-based alloy powder for thermal spraying characterized by In mass%, Cr: 20.0-35.0%, Fe: 0.1-40.0%, C: 0.05-1.20%, Mn: 0.5-2.0%, Si: Contains 0.1 to 3.0%, B: 0.001 to 0.3%, and La: 0.01 to 0.15% and Ce: 0.01 to 0.15% Alternatively, a Co-based alloy powder for thermal spraying, which contains two types and the balance is composed of Co and inevitable impurities. In mass%, Cr: 20.0-35.0%, Fe: 0.1-40.0%, C: 0.05-1.20%, Mn: 0.5-2.0%, Si: It contains 0.1 to 3.0%, B: 0.001 to 0.3%, further contains Mg: 0.001 to 0.05%, and the balance is composed of Co and inevitable impurities. Co-based alloy powder for thermal spraying characterized by In mass%, Cr: 20.0-35.0%, Fe: 0.1-40.0%, C: 0.05-1.20%, Mn: 0.5-2.0%, Si: 0.1 to 3.0%, B: 0.001 to 0.3%, W: 3.0 to 15.0% further, La: 0.01 to 0.15% and Ce: Co-based alloy powder for thermal spraying, characterized in that it contains one or two of 0.01 to 0.15%, and the balance is composed of Co and inevitable impurities. In mass%, Cr: 20.0-35.0%, Fe: 0.1-40.0%, C: 0.05-1.20%, Mn: 0.5-2.0%, Si: 0.1 to 3.0%, B: 0.001 to 0.3%, W: 3.0 to 15.0%, Mg: 0.001 to 0.05% A Co-based alloy powder for thermal spraying, characterized in that it has a composition comprising Co and inevitable impurities. In mass%, Cr: 20.0-35.0%, Fe: 0.1-40.0%, C: 0.05-1.20%, Mn: 0.5-2.0%, Si: Contains 0.1 to 3.0%, B: 0.001 to 0.3%, and La: 0.01 to 0.15% and Ce: 0.01 to 0.15% Alternatively, a Co-based alloy powder for thermal spraying, characterized in that it contains two types, further contains Mg: 0.001 to 0.05%, and the balance is composed of Co and inevitable impurities. In mass%, Cr: 20.0-35.0%, Fe: 0.1-40.0%, C: 0.05-1.20%, Mn: 0.5-2.0%, Si: 0.1 to 3.0%, B: 0.001 to 0.3%, W: 3.0 to 15.0% further, La: 0.01 to 0.15% and Ce: containing one or two of 0.01 to 0.15%, further containing Mg: 0.001 to 0.05%, the balance having a composition consisting of Co and inevitable impurities Characteristic Co-based alloy powder for thermal spraying. A Co-based alloy sprayed layer having excellent erosion resistance against molten lead-free solder having the composition according to claim 1, 2, 3, 4, 5, 6, 7, or 8. A composite member for a lead-free soldering apparatus, wherein a Co-based alloy sprayed layer having excellent erosion resistance against molten lead-free solder according to claim 9 is formed on a base material. A solder bath for a lead-free soldering apparatus, comprising the composite member for a lead-free soldering apparatus according to claim 10. An injection nozzle for a lead-free soldering device, comprising the composite member for a lead-free soldering device according to claim 10. A propeller for a lead-free soldering device comprising the composite member for a lead-free soldering device according to claim 10. A shaft for a lead-free soldering device, comprising the composite member for a lead-free soldering device according to claim 10. A lead-free soldering device duct comprising the composite member for a lead-free soldering device according to claim 10. A heater protective tube for a lead-free soldering device, comprising the composite member for a lead-free soldering device according to claim 10. A heater-coated tube for a lead-free soldering device, comprising the composite member for a lead-free soldering device according to claim 10.