Einzeltreffer — DigiBib

Improved thin film coatings, cutting tool materials and processes for cutting tool applications are disclosed. A boron-doped graded diamond thin film for forming a highly adhesive surface coating on a cemented carbide (WC—Co) cutting tool material is provided. The thin film is fabricated in a HFCVD reactor. It is made of a bottom layer of BMCD in contact with a surface layer of the cemented carbide, a top layer made of NCD and a transition layer with a decreasing concentration gradient of boron obtained by changing the reaction conditions through ramp up option in hot filament CVD reactor. The top layer has a low friction coefficient. The bottom layer in the coating substrate interface has better interfacial adhesion through cobalt and boron reactivity and decreased cobalt diffusivity in the diamond. The transition layer has minimized lattice mismatch and sharp stress concentration between the top and bottom layers.

Titel:	Highly adhesive CVD grown boron doped diamond graded layer on WC-Co
Autor/in / Beteiligte Person:	INDIAN INSTITUTE OF TECHNOLOGY MADRAS (IIT MADRAS)
Link:	View record in USPTO Patent Grants (Volltext)
Veröffentlichung:	2023
Medientyp:	Patent
Sonstiges:	Nachgewiesen in: USPTO Patent Grants Sprachen: English Patent Number: 11739,419 Publication Date: August 29, 2023 Appl. No: 16/608790 Application Filed: April 26, 2018 Assignees: INDIAN INSTITUTE OF TECHNOLOGY MADRAS (IIT MADRAS) (Chennai, IN) Claim: 1. A boron-doped graded diamond thin film for forming a highly adhesive surface coating on a cemented carbide (WC—Co) cutting tool material, comprising: i. a bottom coating layer formed on a surface layer of the cemented carbide material, comprising a boron-doped microcrystalline diamond (BMCD), wherein the concentration of boron in the BMCD layer is between 0.2-0.25%, and wherein the concentration of cobalt in the surface layer is between 0.1-1%; ii. a top coating layer, comprising nanocrystalline diamond (NCD) substantially free of boron; and iii. a transition coating layer formed between the top and bottom layers, comprising a decreasing concentration gradient of boron from the bottom layer to top layer, wherein the concentration of boron in the surface of transition layer in contact with the bottom layer is 0.2-0.25%, and wherein the concentration of boron in the surface of transition layer in contact with top layer is substantially free of boron. Claim: 2. The film of claim 1 , wherein the total thickness is 4-10 microns. Claim: 3. The film of claim 1 , wherein the thickness of the bottom layer is 1-6 microns. Claim: 4. An enhanced cutting tool, comprising: i. A cemented carbide (WC—Co) matrix with a cobalt-depleted surface layer, wherein the matrix comprises 1-6% cobalt and wherein the surface layer comprises 0.1-1% cobalt; ii. a boron-doped graded diamond thin film coated on the cemented carbide matrix, comprising: a) a bottom coating layer formed on the surface layer of the cemented carbide material, comprising a boron-doped microcrystalline diamond (BMCD), wherein the concentration of boron in the bottom layer is between 0.2-0.25%; b) a top coating layer, comprising a nanocrystalline diamond (NCD) substantially free of boron; and c) a transition coating layer formed between the top and bottom layers, comprising a decreasing concentration gradient of boron from 0.2-0.25% in the surface in contact with the bottom layer to the surface in contact with the top layer substantially free of boron. Claim: 5. The cutting tool of claim 4 , wherein the grain size of the top layer is 100 nm-1000 nm. Claim: 6. The cutting tool of claim 4 , wherein the grain size of the bottom layer is 500-1500 nm. Claim: 7. The cutting tool of claim 4 , wherein the grain size of the transition layer is 100 nm-1500 nm. Claim: 8. The cutting tool of claim 4 , wherein the surface roughness value of the cutting tool is 100 nm or lower. Patent References Cited: 5236740 August 1993 Peters ; 20060112648 June 2006 Hanyu ; 20140037932 February 2014 Twitchen ; 20140341664 November 2014 Meguro ; 20170043406 February 2017 Waki ; H04168276 June 1992 ; 05-123905 May 1993 ; 06-285704 October 1994 ; 2006-152423 June 2006 Other References: Srinvasan et al “On the development of dual-layered diamond-coated tool for the effective machining of titanium Ti-6AI-4V alloy” j. Phys. D : Appl Phy 50 p. 1-10. (Year: 2017). cited by examiner ; Lei et al “Effect of Boron-Doped Diamond Interlayer on Cutting Performance of Diamond Coated Micro Drills for Graphite Machining” Materials 6, pp. 3128-3138. (Year: 2013). cited by examiner ; Dumpala et al.,Growth and characterization of integrated nano- and microcrystalline dual layer composite diamond coatings on WC-Co substrates, Int. Journal of Refractory Metals and Hard Materials 37 (2013) , pp. 127-133 (Year: 2013). cited by examiner ; Yao et al., Effect of Boron Concentration on Adhesion and Cutting Performance of Diamond-Coated Cemented Carbide Tools, Key Engineering Materials, vols. 375-376, p. 138-142 (Year: 2008). cited by examiner ; International Search Report and Written Opinion for application No. PCT/IN2018/050258 dated Aug. 17, 2018, 8 pages. cited by applicant Primary Examiner: Collister, Elizabeth Attorney, Agent or Firm: Convergence Intellectual Property Law P.C. ; Garfinkel, Jonathan

Klicken Sie ein Format an und speichern Sie dann die Daten oder geben Sie eine Empfänger-Adresse ein und lassen Sie sich per Email zusenden.

BibTeX Citavi, JabRef, u.a.
(Literaturverwaltung)

PDF kein Volltext!
(Merkzettel, Notizen)

RIS Endnote, Citavi u.a.
(Literaturverwaltung)

MODS
(XML zur Weiterverarbeitung)

oder

Wählen Sie das für Sie passende Zitationsformat und kopieren Sie es dann in die Zwischenablage, lassen es sich per Mail zusenden oder speichern es als PDF-Datei.

Gewünschter Zitations-Stil:

oder

Bitte prüfen Sie, ob die Zitation formal korrekt ist, bevor Sie sie in einer Arbeit verwenden. Benutzen Sie gegebenenfalls den "Exportieren"-Dialog, wenn Sie ein Literaturverwaltungsprogramm verwenden und die Zitat-Angaben selbst formatieren wollen.

Highly adhesive CVD grown boron doped diamond graded layer on WC-Co