Coating processes – Direct application of electrical – magnetic – wave – or... – Pretreatment of substrate or post-treatment of coated substrate
Patent
1996-09-27
1999-02-09
Beck, Shrive
Coating processes
Direct application of electrical, magnetic, wave, or...
Pretreatment of substrate or post-treatment of coated substrate
427249, 4272551, 4272557, 83663, 83679, 409 65, H05H 124, C23C 1630, B26D 100
Patent
active
058691472
DESCRIPTION:
BRIEF SUMMARY
CROSS REFERENCE TO RELATED APPLICATIONS
This application is a national stage of PCT/DE 95/00449 filed 1 Apr. 1995 and based, in turn, on German national application P 44 17 729.1 filed 20 May 1994 under the International Convention.
FIELD OF THE INVENTION
The invention relates to a tool of a base body of a hard metal or cermet and a multilayer surface coating applied by means of a CVD process on the base body and composed of carbides, nitrides and/or carbonitrides of titanium and/or zirconium and/or aluminum oxide according to German Patent Application P 42 39 234.9 corresponding to U.S. patent application Ser. No. 08/446,836, now U.S. Pat. No. 5,693,408 of 2 Dec. 1997.
The invention relates further to a process and to a device for producing this tool as well as to the use of the tool.
BACKGROUND OF THE INVENTION
In German Patent Application P 42 39 234.9 corresponding to U.S. patent application Ser. No. 08/446,836 filed 16 May 1995 now U.S. Pat. No. 5,693,408, a tool of the initially stated type is described in which the surface coating is comprised of a plurality of layers deposited in an alternating sequence by a thermal CVD process and by a glow discharge activated CVD process also known as plasma chemical vapor deposition (PCVD). The total thickness of the coating amounts to 2 through 40 .mu.m whereby each individual layer is thicker than 0.2 .mu.m.
The individual layers are applied by technically different processes. In the (thermal) CVD process one must use temperatures in excess of 900.degree. C. and pressures above 10,000 Pa to achieve sufficiently high coating rates. Thus, in an example of the aforementioned patent application, a gas mixture of 2.5% TiCl.sub.4, 35% N.sub.2 and 62.5 H.sub.2 is passed over the substrate to be coated at a temperature of 940.degree. C. and a pressure of 25000 Pa. Thereafter or alternatingly thereto, individual layers are applied by the PCVD processes whereby, for example, a gas mixture of 1.5% TiCl.sub.4, 11.5% N.sub.2, 8% Ar and 79% H.sub.2 is used at a pressure of 300 Pa and a temperature of 780.degree. C. The multilayer coating of CVD layers and PCVD layers gives an unusually good mechanical stability to the coating which yields a high useful life for tools fabricated by the process reviewed in chip removal operations. The special advantage of the alternating coating by means of the CVD process and PCVD process is that in a single coating apparatus in a continuous process without intervening coating and removal of the object to be coated, the coatings can be applied.
OBJECTS OF THE INVENTION
It is the object of the present invention to provide a tool of the initially mentioned type whose coating is fine grained. It is a further object of the present invention to provide a process and an apparatus with which these coatings can be deposited.
SUMMARY OF THE INVENTION
This object is achieved in a tool of a base body of hard metal or cermet and a multilayer surface coating applied to the base body. The coating is comprised of carbides, nitrides and/or carbonitrides of titanium and/or zirconium and/or aluminum oxide by means of a CVD process according to German patent application P 42 39 234.9, corresponding to U.S. patent application Ser. No. 08/446,836 filed 16 May 1995, now U.S. Pat. No. 5,693,408 whereby the CVD process is interrupted a multiplicity of time by a plasma treatment at substantially the same high temperature, in a gas or gas mixture of argon, hydrogen and/or nitrogen admitted to the coating vessel at a pressure of 10 to 1000 Pa and with a glow discharge on the cathodically connected base body or partly coated base body by the application of a negative DC voltage maintained at 200 to 1000 V for 1 to 30 minutes.
With this tool, the CVD coating is interrupted a multiplicity of times by a plasma treatment while substantially maintaining the high temperature while a nonreactive gas mixture is applied during this plasma treatment of argon, hydrogen, and/or nitrogen at a low pressure of 10 to 1000 Pa so that on the last layer applied by means of C
REFERENCES:
patent: 4910041 (1990-03-01), Yanagihara et al.
patent: 5079031 (1992-01-01), Yamazaki et al.
patent: 5271963 (1993-12-01), Eichman et al.
patent: 5300951 (1994-04-01), Yamazaki
patent: 5346600 (1994-09-01), Nieh et al.
patent: 5503913 (1996-04-01), Konig et al.
patent: 5516588 (1996-05-01), Van Den Berg et al.
patent: 5576071 (1996-11-01), Sandhu
"Characterization of .alpha.-Al.sub.2 -O.sub.3, .kappa.-Al.sub.2 O.sub.3, and .alpha.-.kappa. multioxide coatings on cemented carbides" by S. Vuorinen, published in Thin Solid Films,/93/94(1990)536-546.
Beck Shrive
Chen Bret
Dubno Herbert
Widia GmbH
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