Coating processes – With post-treatment of coating or coating material – Heating or drying
Patent
1997-09-18
2000-03-07
Beck, Shrive
Coating processes
With post-treatment of coating or coating material
Heating or drying
4273831, 4273833, 4273835, 427377, B05D 302, B05D 304
Patent
active
060337354
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to a method of coating cutting tool inserts with a layer of an iron group metal. Inserts with a coating applied according to the invention are particularly suitable for brazing.
Cemented carbide inserts are generally attached to tool-holders by mechanical means if possible. In case of saw-blades, drills and circular cutters, the design does not permit mechanical clamps and/or similar mechanical attachments. In these cases the inserts have to be brazed to the toolholder.
When brazing cemented carbide with a low binder content there are problems with the wetting of the braze and therefore the inserts have to be coated with cobalt prior to the brazing procedure. For coating on industrial scale, this cobalt coating is generally made electrolytically. However, such coating generally has poor adherence. In order to improve the adhesion, the inserts are heat treated in a subsequent production step. This coating method is rather complex and expensive and the resultant coating adhesion is still not always satisfactory.
OBJECTS AND SUMMARY OF THE INVENTION
It is an object of this invention to avoid or alleviate the problems of the prior art.
It is further an object of this invention to provide a method of coating cutting tool inserts with a layer of an iron group metal.
It is an aspect of the invention to provide a method of coating metal composite bodies formed of carbides, nitrides, carbonitrides with a binder phase of Co and/or Ni at least partly with a layer of at least one iron group metal comprising the following steps: metal containing organic groups in at least one polar solvent with at least one complex former comprising functional groups of OH or NR.sub.3, where R.dbd.H or alkyl; improve the wetting properties into the solution; or painting; obtain said bodies at least partly coated with said at least one iron group metal.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows in 150.times. the surface structure of the coating of cemented carbide insert coated with the method of the present invention.
FIG. 2 shows in 1250.times. the microstructure and the thickness of the coating from the cross section of a T-shape crack in the coating. The network of the coating is observed clearly. The crack has been formed during the cooling step because of difference in thermal expansion coefficient between coating and cemented carbide.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION
It has now surprisingly been found that using a technique related to the SOL-GEL technique, cemented carbide inserts can be provided with a cobalt layer with improved bond to the tool.
According to the method of the present invention one or more metal salts of at least one iron group metal containing organic groups are dissolved and complex bound in at least one polar solvent with at least one complex former comprising functional groups in the form of OH or NR.sub.3, (R.dbd.H or alkyl). Optionally, a soluble carbon source is added to the solution which is applied onto the cemented carbide inserts. The solvent is evaporated and the coated inserts are heat treated in an inert and/or reducing atmosphere. As a result, coated cemented carbide inserts are obtained which can be brazed to a tool according to standard practice.
The process according to the invention comprises the following steps where Me.dbd.Co, Ni and/or Fe, preferably Co:
1. At least one Me-salt containing organic groups such as carbo-oxylates, acetyl-acetonates, nitrogen containing organic groups such as Schiff bases, preferably Me-acetates, is dissolved in at least one polar solvent such as ethanol, acetonitrile, dimetyl-formamide or dimethyl-sulfoxide and combinations of solvent such as methanol-ethanol and water-glycol, preferably methanol. Triethanolamine or other complex former, especially molecules containing more than two functional groups, i.e., OH or NR.sub.3 with R.dbd.H or alkyl(0.1-2.0 mole complex former/mole metal, preferably about 0.5 mole complex former/mole metal) is added under stirr
REFERENCES:
patent: 3011920 (1961-12-01), Shipley, Jr.
patent: 3620834 (1971-11-01), Duffy
patent: 3915665 (1975-10-01), Kalish
patent: 3947616 (1976-03-01), Ritsko et al.
patent: 4072781 (1978-02-01), Shirahata et al.
patent: 4907665 (1990-03-01), Kar et al.
patent: 4914813 (1990-04-01), Layher et al.
patent: 5134039 (1992-07-01), Alexander et al.
Umehara et al., "Electroless plating method", 58-104169, Japanese patent abstracts, abstract, Jun. 21, 1983.
Chemical Abstracts, vol. 121, No. 10, Sep. 5, 1994, (Columbus, Ohio, USA), p. 438, The Abstract No. 115335x,JP,649651,A, (Nippon Aluminum Mfg) Feb. 22, 1994.
Patent Abstracts of Japan, vol. 8, No. 99, E-243, abstract of JP,A,59-17223 (Nippon Denki K.K.), Jan. 28, 1984.
Patent Abstracts of Japan, vol. 13, No. 501, C-652, abstract of JP,A,1-201091 (Ibiden Co Ltd), Aug. 14, 1989.
Ederyd Stefan
Ekstrand Asa
Galli Enrico
Nygren Mats
Westin Gunnar
Barr Michael
Beck Shrive
Sandvik AB
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