Stock material or miscellaneous articles – Web or sheet containing structurally defined element or... – Including a second component containing structurally defined...
Patent
1994-08-30
1996-12-24
Pianalto, Bernard
Stock material or miscellaneous articles
Web or sheet containing structurally defined element or...
Including a second component containing structurally defined...
427314, 427318, 427327, 427569, 427576, 427585, 428329, 428336, 4284722, 428698, 428699, B32B 1800
Patent
active
055872336
DESCRIPTION:
BRIEF SUMMARY
CROSS REFERENCE TO RELATED APPLICATIONS
This application is a national phase of PCT/DE 93 00 047 filed 21 Jan. 1993 and based upon German national application P 42 09 975.7 of 27 Mar. 1992 under the International Convention.
FIELD OF THE INVENTION
The invention relates to a composite body, consisting of a substrate body made of ceramic, sintered ceramic or cermet or of a substrate body made of diamond or a nickel- or cobalt-based alloy with one or more surface layers and its use.
BACKGROUND OF THE INVENTION
DE 22 33 700 C2 discloses coating hard metal substrate bodies consisting of a mixture of at least one metal serving as a bonding agent and at least one very hard metal carbide of high with a layer of aluminum oxide or zirconium oxide. Particularly the substrate body can be made of tungsten carbide, titanium carbide, tantalum carbide or niobium carbide, or, a compound carbide consisting of tantalum and niobium, whereby the metals cobalt, iron or nickel serve as bonding agent. In the literature hard metals based titanium carbide or titanium carbonitride are frequently mentioned as cermets, which are also to be understood as substrate materials, just like the pure combinations of a hard metal with ceramic, i.e. nonmetallic, components. According to the DE 22 33 700 C2 the mentioned layers of .alpha.-aluminum oxide are applied by means of CVD at substrate temperatures of 1000.degree. C.
A corresponding layer may be applied to the hard metal bodies according to the DE 22 53 745 A1, which consist of a sintered hard metal substrate body, intermediate layers of titanium carbide and an outer layer of aluminum oxide, whereby the first titanium carbide intermediate layer has to be applied at 1000.degree. C. and the second aluminum oxide layer at 1110.degree. C. by a CVD process. As mentioned especially in DE 28 25 009, column 2, lines 28 and following, hard, polycrystalline and compact .alpha.-aluminum oxide layer are normally produced only at deposition temperatures of 950.degree. C. At lower deposition temperatures, according to the state of the art, loose and powdery depositions are obtained, which consist of the .gamma. modification and/or .alpha. modification of the aluminum oxide. At deposition temperatures of approximately 1000.degree. C. and above, the aluminum oxide phase is normally the .chi.-modification considered suitable for the coating of tools. In order to prevent the danger of obtaining multiphase aluminum oxide coatings, which presumably occur at temperatures below 1000.degree. C. and which show a considerable mechanical weakness causing premature tool failure, it is proposed that the coating of aluminum oxide consist entirely or at least in proportion of 85% of the .chi.-modification and that an optional remainder consisting of the .alpha.-modification form areas or spots not exceeding a size of 10 .mu.m on the surface. For the deposition the CVD process at temperatures of approximately 1000.degree. C. is suggested. However, this type of coating tends to convert into the .alpha.-modification under the action of high temperatures, so that cracks appear in the layer, leading to premature failure especially under the action of hot gas corrosion.
In order to avoid the problems occurring at high deposition temperatures, the DE 32 34 943 discloses the deposition of an amorphous aluminum oxide layer. However, intensive testing with amorphous aluminum oxide layers, deposited by means of PVD, have shown that purely amorphous aluminum oxide layers have a glass-like breaking behavior, and therefore can not offer any significant improvement in wear resistance. In the case of interrupted cuts, these layers tend to split.
In the DE 24 28 530 A1 a process for the protection of a metallic part against corrosion and wear is proposed, which in the pure or alloyed state contains at least one element of the Group I B of the periodic system of elements and wherein on the surface of this part a layer of amorphous and transparent aluminum oxide is deposited by chemical deposition from the vapor phase. However t
REFERENCES:
"Physical and Chemical Properties of Aluminum Oxide Film Deposited b AlCl3-CO2-H2 System" by Iida et al. (Japanese Journal of Applied Physics vol. 11, No. 6 Jun. 1972.
"Carbon-Doped aplha-Al2O3 Films Synthesized on Cemented Carbide Tools by the Metal Organic LPCVD Technique" by A. Kwatera (2194 Thin Solid Films, 200 (1991) May/1, No. 1, Lausanne.
"Properties of Aluminium Oxide Films Prepared by Plasma-Enhanced Metal-Organic Vapour Deposition" Chang et al. (2194 Thin Solid Films 189 (1990) Aug. 1, No. 1 Lausanne.
Konig Udo
Tabersky Ralf
van den Berg Hendrikus
Dubno Herbert
Pianalto Bernard
Widia GmbH
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