Alpha alumina thin film for processing difficult-to-cut material and cast iron

Patent metadata

Field	Value
Publication number	US-2016298232-A1
Application number	US-201415038474-A
Country	US
Kind code	A1
Filing date	Nov 26, 2014
Priority date	Dec 23, 2013
Publication date	Oct 13, 2016
Grant date	—

Abstract

Disclosed is an alpha alumina (α-Al2O3) thin film comprising the lower layer formed on the base material made from cemented carbide; and the α-Al2O3 thin film layer formed on the lower layer, wherein when the α-Al2O3 thin film layer is divided, from the total thickness (T) thereof, into a D1 layer which is from an interface layer to 0.15T, a D2 layer which is from 0.15T to 0.4T, and a D3 layer which is from 0.4T to 1T, an S1 (D3 layer grain size/D1 layer grain size) is 2-5.5 and an S2 (D2 layer grain size/D1 layer grain size) is 1.5-4.

First claim

1 . An alpha alumina (α-Al 2 O 3 ) thin film which has a thickness of T and is formed on a lower layer which is formed on a base material, the α-Al 2 O 3 thin film being divided into:
a D1 layer which is positioned between an interfacial layer and 0.15T above the interfacial layer;
a D2 layer which is positioned between 0.15T and 0.4T above the interfacial layer; and
a D3 layer which is positioned between 0.4T and 1T above the interfacial layer,
wherein S1 (the grain size of the D3 layer/the grain size of the D1 layer) is 2 to 5.5, and S2 (the grain size of the D2 layer/the grain size of the D1 layer) is 1.5 to 4.

2 . The α-Al 2 O 3 thin film of claim 1 , wherein the base material is a cemented carbide containing 5 to 10 wt % of Co, and at most 1 wt % of (Ta,Nb)C.

3 . The α-Al 2 O 3 thin film of claim 1 , wherein the lower layer comprises:
a TiN layer formed on the base material;
a MT-TiCN layer formed on the TiN layer; and
an interfacial layer containing Ti and formed on the TiCN layer.

4 . The α-Al 2 O 3 thin film of claim 3 , wherein:
the thickness of the TiN layer is 0.1 to 2 μm;
the thickness of the MT-TiCN layer is 3 to 10 μm;
the thickness of the interfacial layer is 0.1 to 1 μm; and
the thickness of the α-Al 2 O 3 layer is 2 to 8 μm.

5 . The α-Al 2 O 3 thin film of claim 1 , wherein:
the grain size of the D1 layer is 0.1 to 0.5 μm;
the grain size of the D2 layer is 0.15 to 0.8 μm; and
the grain size of the D3 layer is 0.4 to 1.5 μm.

6 . The α-Al 2 O 3 thin film of claim 3 , wherein the interfacial layer comprises:
a Ti x Al 1-x CNO layer formed on the MT-TiCN layer;
a Al y Ti 1-y CNO layer formed on the TixAl1-xCNO layer; and
a Ti oxide layer formed on the Al y Ti 1-y CNO layer.

7 . The α-Al 2 O 3 thin film of claim 1 , wherein the surface roughness (Ra) of the α-Al 2 O 3 thin film is at most 250 nm.

Assignees

• Korloy Inc

Inventors

• Kang Jae Hoon
• Lee Dong Youl
• Kim Jung Wook
• Kim Han Sung
• Lee Sung Gu
• Ahn Jin Woo
• Ahn Sun Yong

Classifications

• C23C28/048

  with layers graded in composition or physical properties · CPC title

• C23C28/028 Primary

  Including graded layers in composition or in physical properties, e.g. density, porosity, grain size · CPC title

• C23C16/06 Primary

  characterised by the deposition of metallic material · CPC title

• C23C16/44

  characterised by the method of coating (C23C16/04 takes precedence) · CPC title

• C23C28/044 Primary

  coatings specially adapted for cutting tools or wear applications · CPC title